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Henley's Book of Formulas, Recipes and Processes

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Henley's Twentieth Century Book of Formulas, Recipes and Processes - Pages 351-375

 

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Detection of Formaldehyde. Formaldehyde is rarely used with other foods than milk. The method for its detection in milk is given later. For its detection in other foods it is usually necessary first to separate it by distillation, a process which is scarcely available for the average person without laboratory training and special apparatus. For this reason no method is suggested here for the detection of formaldehyde in other foods than milk.

 

Detection of Saccharine. Saccharine has a certain preservative power, but it is used not so much for this effect as because of the very sweet taste which it imparts. It is extracted by means of chloroform, as described under the detection of salicylic acid. In the case of solid and semi-solid foods, the sample must, of course, be prepared by extraction with water, as described under salicylic acid. The residue left after the evaporation of the chloroform, if a considerable amount of saccharine is present, has a distinctly sweet taste.

 

The only other substance having a sweet taste which may be present in foods, i.e., sugar, is not soluble in chloroform, and therefore does not interfere with this reaction. Certain other bodies (tannins) which have an astringent taste are present, and as they are soluble in chloroform may sometimes mask the test for saccharine, but with practice this difficulty is obviated.

 

Determination of Artificial Colors: Detection of Coal-Tar Dyes. Coloring matters used with foods are usually soluble in water. If the food under examination be a liquid, it may therefore be treated directly by the method given below. If it be a solid or a pasty substance, soluble in water either in the cold or after heating, it may be dissolved in sufficient water to form a thin liquid. If it contains some insoluble material, it may be treated with sufficient water to dissolve the soluble portion with the formation of a thin liquid and filtered, and then strained through a clean white cotton cloth to separate the insoluble portion. About a half teacupful of the liquid thus described is heated to boiling, after adding a few drops of hydrochloric acid and a small piece of white woolen cloth or a few strands of white woolen yarn. (Before using, the wool should be boiled with water containing a little soda, to remove any fat it may contain, and then washed with water.) The wool is again washed, first with hot and then with cold water, the water pressed out as completely as possible, and the color of the fabric noted. If no marked color is produced, the test may be discontinued and the product considered free from artificial colors. If the fabric is colored, it may have taken up coal-tar colors, some foreign vegetable colors, and if a fruit product is being examined, some of the natural coloring matter of the fruit.

Rinse the fabric in hot water, and then boil for 2 or 3 minutes in about one-third of a teacupful of water and 2 or 3 teaspoonfuls of household ammonia. Remove and free from as much of the liquid as possible by squeezing or wringing. Usually the fabric will retain the greater part of the natural fruit color, while the coal-tar color dissolves in dilute ammonia. The liquid is then stirred with a splinter of wood and hydrochloric acid added, a drop or two at a time, until there is no longer any odor of ammonia. (The atmosphere of the vessel is sometimes charged with the ammonia for several minutes after it has all been driven out of the liquid; therefore one should blow into the dish to remove this air before deciding whether the ammonia odor has been removed or not.) When enough acid has been added the liquid has a sour taste, as may be determined by touching the splinter, used in stirring, to the tongue.

 

A fresh piece of white woolen cloth is boiled in this liquid and thoroughly washed. If this piece of cloth has a distinct color the food under examination is artificially colored. The color used may have been a coal-tar derivative, commonly called an aniline dye, or an artificial color chemically prepared from some vegetable color. If of the first class the dyed fabric is usually turned purple or blue by ammonia. In either case, if the second fabric has a distinct color, it is evident that the product under examination is artificially colored. Of course a dull, faint tint must be disregarded.

 

Detection of Copper. The presence of copper, often used to deepen the green tint of imported canned peas, beans, spinach, etc., may be detected as follows:

 

Mash some of the sample in a dish with a stiff kitchen spoon. Place a teaspoonful of the pulp in a teacup with 3 teaspoonfuls of water and add 30 drops of strong hydrochloric acid with a medicine dropper. Set the cup on the stove in a saucepan containing boiling water. Drop a bright iron brad or nail (wire nails are the best and tin carpet tacks

 


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will not answer the purpose) into the cup and keep the water in the saucepan boiling for 20 minutes, stirring the contents of the cup frequently with a splinter of wood. Pour out the contents of the cup and examine the nail. If present in an appreciable amount the nail will be heavily plated with copper.

 

Caution. Be careful not to allow the hydrochloric acid to come in contact with metals or with the flesh or clothing.

 

Detection of Turmeric. In yellow spices, especially mustard and mace, turmeric is often employed. This is especially true of prepared mustard to which a sufficient amount of starch adulterant has been added to reduce the natural color materially. If turmeric be employed to restore the normal shade an indication of that fact may sometimes be obtained by mixing a half teaspoonful of the sample in a white china dish and mixing with it an equal amount of water, and a few drops (4 to 10) of household ammonia, when a marked brown color, which does not appear in the absence of turmeric, is formed. At the present time turmeric or a solution of curcuma (the coloring matter of turmeric) is sometimes added to adulterated mustard in sufficient amount to increase its color, but not to a sufficient extent to give the brown appearance with ammonia described above. In such cases a teaspoonful of the suspected sample may be thoroughly stirred with a couple of tablespoonfuls of alcohol, the mixture allowed to settle for 15 minutes or more, and the upper liquid poured off into a clean glass or bottle. To about 1 tablespoonful of the liquid thus prepared and placed in a small, clear dish (a glass salt cellar serves excellently) add 4 or 5 drops of a concentrated solution of boric acid or borax and about 10 drops of hydrochloric acid, and mix the solution by stirring with a splinter of wood. A wedge-shaped strip of filter paper, about 2 or 3 inches long, 1 inch wide at the upper end, and 1/4 inch at the lower end, is then suspended by pinning, so that its narrow end is immersed in the solution, and is allowed to stand for a couple of hours. The best results are obtained if the paper is so suspended that air can circulate freely around it, i.e, not allowing it to touch anything except the pin and the liquid in the dish. If turmeric be present a cherry-red color forms on the filter paper a short distance below the upper limit to which the liquid is absorbed by the paper, frequently from 3/4 of an inch to an inch above the surface of the liquid itself. A drop of household ammonia changes this red color to a dark green, almost black. If too much hydrochloric acid is used a dirty brownish color is produced.

 

Detection of Caramel. A solution of caramel is used to color many substances, such as vinegar and some distilled liquors. To detect it two test tubes or small bottles of about equal size and shape should be employed and an equal amount (2 or 3 tablespoonfuls or more) of the suspected sample placed in each. To one of these bottles is added a teaspoonful of fuller's earth, the sample shaken vigorously for 2 or 3 minutes, and then filtered through filter paper, the first portion of the filtered liquid being returned to the filter paper and the sample finally collected into the test tube or bottle in which it was originally placed, or a similar one. The filtered liquid is now compared with the untreated sample. If it is markedly lighter in color it may be taken for granted that the color of the liquid is due to caramel, which is largely removed by fuller's earth. In applying this test, however, it must be borne in mind that caramel occurs naturally in malt vinegar, being formed in the preparation of the malt. It is evident that the tests require practice and experience before they can be successfully performed. The housewife can use them, but must repeat them frequently in order to become proficient in their use.

 

EXAMINATION OF CERTAIN CLASSES OF FOODS:

 

Canned Vegetables. These are relatively free from adulteration by means of foreign substances. The different grades of products may with care be readily detected by the general appearance of the sample. The purchaser is, of course, at the disadvantage of not being able to see the product until the can is opened. By a study of the different brands available in the vicinity, however, he can readily select those which are preferable. As stated in an earlier part of this article, canned tomatoes sometimes contain an artificial coloring matter, which may be detected as described.

 

Canned sweet corn is sometimes sweetened with saccharine, which may be detected as described.

 

It is believed that, as a rule, canned vegetables are free from preservatives, although some instances of chemical preservation have recently been reported in North Dakota, and some imported

 


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tomatoes have been found to be artificially preserved. The presence of copper, often used for the artificial greening of imported canned peas, beans, spinach, etc., may be detected as described.

 

Coffee. There are a number of simple tests for the presence of the adulterants of ground coffee. These are called simple because they can be performed without the facilities of the chemical laboratory, and by one who has not had the experience and training of a chemist. It must be understood that they require careful observation and study, and that one must perform them repeatedly in order to obtain reliable results. Before applying them to the examination of an unknown sample, samples of known character should be secured and studied. Unground coffee may be ground in the home and mixed with various kinds of adulterants, which can also be secured separately. Thus the articles themselves in known mixtures may be studied, and when the same results are obtained with unknown samples they can be correctly interpreted. These tests are well known in the laboratory and may be used in the home of the careful housewife who has the time and perseverance to master them.

 

Physical Tests. The difference between the genuine ground coffee and the adulterated article can often be detected by simple inspection with the naked eye. This is particularly true if the product be coarsely crushed rather than finely ground. In such condition pure coffee has a quite uniform appearance, whereas the mixtures of peas, beans, cereals, chicory, etc., often disclose their heterogeneous nature to the careful observer. This is particularly true if a magnifying glass be employed. The different articles composing the mixture may then be separated by the point of a pen-knife. The dark, gummy-looking chicory particles stand out in strong contrast to the other substances used, and their nature can be determined by one who is familiar with them by their astringent taste.

 

The appearance of the coffee particles is also quite distinct from that of many of the coffee substitutes employed. The coffee has a dull surface, whereas some of its substitutes, especially leguminous products, often present the appearance of having a polished surface.

 

After a careful inspection of the sample with the naked eye, or, better, with a magnifying glass, a portion of it may be placed in a small bottle half full of water and shaken. The bottle is then placed on the table for a moment. Pure coffee contains a large amount of oil, by reason of which the greater portion of the sample will float. All coffee substitutes and some particles of coffee sink to the bottom of the liquid. A fair idea of the purity of the sample can often be determined by the proportion of the sample which floats or sinks.

 

Chicory contains a substance which dissolves in water, imparting a brownish-red color. When the suspected sample is dropped into a glass of water, the grains of chicory which it contains may be seen slowly sinking to the bottom, leaving a train of a dark-brown colored liquid behind them. This test appears to lead to more errors in the hands of inexperienced operators than any other test here given. Wrong conclusions may be avoided by working first with known samples of coffee and chicory as suggested above.

 

Many coffee substitutes are now sold as such and are advertised as more wholesome than coffee. Notwithstanding the claims that are made for them, a few of them contain a considerable percentage of coffee. This may be determined by shaking a teaspoonful in a bottle half full of water, as described above. The bottle must be thoroughly shaken so as to wet every particle of the sample. Few particles of coffee substitutes will float.

 

Chemical Tests. Coffee contains no starch, while all of the substances, except chicory, used for its adulteration and in the preparation of coffee substitutes contain a considerable amount of starch. The presence of such substitutes may, therefore, be detected by applying the test for starch. In making this test less than a quarter of a teaspoonful of ground coffee should be used, or a portion of the ordinary infusion prepared for the table may be employed after dilution. The amount of water that should be added can only be determined by experience.

 

Condimental Sauces. Tomato catsup and other condimental sauces are frequently preserved and colored artificially. The preservatives employed are usually salicylic acid and benzoic acid or their sodium salts. These products may be detected by the methods given. Coal-tar colors are frequently employed with this class of goods, especially with those of a reddish tint, like tomato catsup. They may be detected by the methods given.

 


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DAIRY PRODUCTS:

 

Butter. Methods are available which, with a little practice, may be employed to distinguish between fresh butter, renovated or process butter, and oleomargarine.

 

These methods are commonly used in food and dairy laboratories. They give reliable results. At the same time considerable practice is necessary before we can interpret correctly the results obtained. Some process butters are on the market which can be distinguished from fresh butter only with extreme difficulty. During the last few years considerable progress has been made in the attempt to renovate butter in such a way that it will appear like fresh butter in all respects. A study must be made of these methods if we would obtain reliable results.

 

The "spoon" test has been suggested as a household test, and is commonly used by analytical chemists for distinguishing fresh butter from renovated butter and oleomargarine. A lump of butter, 2 or 3 times the size of a pea, is placed in a large spoon and heated over an alcohol or Bunsen burner. If more convenient the spoon may be held above the chimney of an ordinary kerosene lamp, or it may even be held over an ordinary illuminating gas burner. If the sample in question be fresh butter it will boil quietly, with the evolution of many small bubbles throughout the mass which produce a large amount of foam.

Oleomargarine and process butter, on the other hand, sputter and crackle, making a noise similar to that heard when a green stick is placed in a fire. Another point of distinction is noted if a small portion of the sample be placed in a small bottle and set in a vessel of water sufficiently warm to melt the butter. The sample is kept melted from half an hour to an hour, when it is examined. If renovated butter or oleomargarine, the fat will be turbid, while if genuine fresh butter the fat will almost certainly be entirely clear.

 

To manipulate what is known as the "Waterhouse" or "milk" test, about 2

ounces of sweet milk are placed in a wide-mouthed bottle, which is set in a vessel of boiling water. When the milk is thoroughly heated, a teaspoonful of butter is added, and the mixture stirred with a splinter of wood until the fat is melted. The bottle is then placed in a dish of ice water and the stirring continued until the fat solidifies. If the sample be butter, either fresh or renovated, it will be solidified in a granular condition and distributed through the milk in small particles. If, on the other hand, the sample consist of oleomargarine it solidifies practically in one piece and may be lifted by the stirrer from the milk.

 

By these two tests, the first of which distinguishes fresh butter from process or renovated butter and oleomargarine, and the second of which distinguishes oleomargarine from either fresh butter or renovated butter, the nature of the sample under examination may be determined.

 

Milk. The oldest and simplest method of adulterating milk is by dilution with water. This destroys the natural yellowish-white color and produces a bluish tint, which is sometimes corrected by the addition of a small amount of coloring matter.

 

Another form of adulteration is the removal of the cream and the sale as whole milk of skimmed or partially skimmed milk. Again, the difficulty experienced in the preservation of milk in warm weather has led to the widespread use of chemical preservatives.

 

Detection of Water. If a lactometer or hydrometer, which can be obtained of dealers in chemical apparatus, be available, the specific gravity of milk will afford some clew as to whether the sample has been adulterated by dilution with water. Whole milk has a specific gravity between 1.027 and 1.033. The specific gravity of skimmed milk is higher, and milk very rich in cream is sometimes lower than these figures. It is understood, of course, that by specific gravity is meant the weight of a substance with reference to the weight of an equal volume of water. The specific gravity of water is 1. It is obvious that if water be added to a milk with the specific gravity of 1.030, the specific gravity of the mixture will be somewhat below those figures.

 

An indication by means of a hydrometer or lactometer below the figure 1.027 therefore indicates either that the sample in question is a very rich milk or that it is a milk (perhaps normal, perhaps skimmed) that has been watered. The difference in appearance and nature of these two extremes is sufficiently obvious to make use of the lactometer or hydrometer of value as a preliminary test of the purity of milk.

 

Detection of Color. As previously stated, when milk is diluted by means of water the natural yellowish-white color is changed to a bluish tint, which is sometimes corrected by the addition

 


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of coloring matter. Coal-tar colors are usually employed for this purpose. A reaction for these colors is often obtained in the method given below for the detection of formaldehyde. When strong hydrochloric acid is added to the milk in approximately equal proportions before the mixture is heated a pink tinge sometimes is evident if a coal-tar color has been added.

 

Detection of Formaldehyde. Formaldehyde is the substance most commonly used for preserving milk and is rarely, if ever, added to any other food. Its use is inexcusable and especially objectionable in milk served to infants and invalids.

 

To detect formaldehyde in milk 3 or 4 tablespoonfuls of the sample are placed in a teacup with at least an equal amount of strong hydrochloric acid and a piece of ferric alum about as large as a pinhead, the liquids being mixed by a gentle rotary motion. The cup is then placed in a vessel of boiling water, no further heat being applied, and left for 5 minutes. At the end of this time, if formaldehyde be present, the mixture will be distinctly purple. If too much heat is applied, a muddy appearance is imparted to the contents of the cup.

 

Caution. Great care must be exercised in working with hydrochloric acid, as it is strongly corrosive.

 

Edible Oils. With the exception of cottonseed oil, the adulterants ordinarily used with edible oils are of such a nature that the experience of a chemist and the facilities of a chemical laboratory are essential to their detection. There is, however, a simple test for the detection of cottonseed oil, known as the Halphen test, which may be readily applied.

 

Great care must be taken in the manipulation of this test, as one of the reagents employed carbon bisulphide is very inflammable. The chemicals employed in the preparation of the reagent used for this test are not household articles. They may, however, be obtained in any pharmacy. The mixture should be prepared by a druggist rather than by an inexperienced person who desires to use it.

 

In order to perform the test 2 or 3 tablespoonfuls of this reagent are mixed in a bottle with an equal volume of the suspected sample of oil and heated in a vessel of boiling salt solution (prepared by dissolving 1 tablespoonful of salt in a pint of water) for 10 or 15 minutes. At the end of that time, if even a small percentage of cottonseed oil be present, the mixture will be of a distinct reddish color, and if the sample consists largely or entirely of cottonseed oil, the color will

be deep red.

 

Eggs. There is no better method for the testing of the freshness of an egg than the familiar one of "candling," which has long been practiced by dealers. The room is darkened and the egg held between the eye and a light; the presence of dark spots indicates that the egg is not perfectly fresh, one that is fresh presenting a homogeneous, translucent appearance. Moreover, there is found in the larger end of a fresh egg, between the shell and the lining membrane, a small air cell which, of course, is distinctly transparent. In an egg which is not perfectly fresh this space is filled and hence presents the same appearance as the rest of the egg.

 

It is now a matter of considerable importance to be able to distinguish between fresh eggs and those that have been packed for a considerable time. Until recently that was not a difficult matter. All of the solutions that were formerly extensively used for that purpose gave the shell a smooth, glistening appearance which is not found in the fresh egg. This characteristic, however, is of less value now than formerly, owing to the fact that packed eggs are usually preserved in cold storage. There is now no means by which a fresh egg can be distinguished from a packed egg without breaking it. Usually in eggs that have been packed for a considerable time the white and yolk slightly intermingle along the point of contact, and it is a difficult matter to separate them. Packed eggs also have a tendency to adhere to the shell on one side and when opened frequently have a musty odor.

 

FLAVORING EXTRACTS.

 

Although a large number of flavoring extracts are on the market, vanilla and lemon extracts are used so much more commonly than other flavors that a knowledge of their purity is of the greatest importance. Only methods for the examination of those two products will be considered.

 

Vanilla Extract. Vanilla extract is made by extracting vanilla beans with alcohol. It consists of an alcoholic solution of vanillin (the characteristic flavoring matter of the vanilla bean) and several other products, chiefly rosins, which, though present in but small amount and having only a slight flavor in themselves, yet affect very materially

 


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the flavor of the product. Vanilla extract is sometimes adulterated with the extract of the Tonka bean. This extract, to a certain extent, resembles vanilla extract. The extract of the Tonka bean, however, is far inferior to that of the vanilla bean. It has a relatively penetrating, almost pungent odor, standing in sharp contrast to the flavor of the vanilla extract. This odor is so different that one who has given the matter some attention may readily distinguish the two, and the quality of the vanilla extract may often be judged with a fair degree of accuracy by means of the odor alone.

 

Another form of adulteration, and one that is now quite prevalent, is the use of artificial vanillin in place of the extract of either vanilla or Tonka beans. Artificial vanillin has, of course, the same composition and characteristics as the natural vanillin of the vanilla bean. Extracts made from it, however, are deficient in the rosins and other products which are just as essential to the true vanilla, as is vanillin itself. Since vanillin is thus obtained from another source so readily, methods for the determination of the purity of vanilla extract must depend upon the presence of other substances than vanillin.

 

Detection of Caramel. The coloring matter of vanilla extract is due to substances naturally present in the vanilla bean and extracted therefrom by alcohol. Artificial extracts made by dissolving artificial vanillin in alcohol contain no color of themselves and to supply it caramel is commonly employed. Caramel may be detected in artificial extracts by shaking and observing the color of the resulting foam after a moment's standing. The foam of pure extracts is colorless. If caramel is present a color persists at the points of contact between the bubbles until the last bubble has disappeared. The test with fuller's earth given for caramel in vinegar is also very satisfactory, but of course requires the loss of the sample used for the test.

 

Examination of the Rosin. If pure vanilla extract be evaporated to about one-third its volume the rosins become insoluble and settle to the bottom of the dish. Artificial extracts remain clear under the same conditions. In examining vanilla extract the character of these rosins is studied. For this purpose a dish containing about an ounce of the extract is placed on a teakettle or other vessel of boiling water until the liquid evaporates to about one-third or less of its volume. Owing to the evaporation of the alcohol the rosins will then be insoluble. Water may be added to restore the liquid to approximately its original volume. The rosin will then separate out as a brown flocculent precipitate. A few drops of hydrochloric acid may be added and the liquid stirred and the insoluble matter allowed to settle. It is then filtered and the rosin on the filter paper washed with water. The rosin is then dissolved in a little alcohol, and to 1 portion of this solution is added a small particle of ferric alum, and to another portion a few drops of hydrochloric acid. If the rosin be that of the vanilla bean, neither ferric alum nor hydrochloric acid will produce more than a slight change of color. With rosins from most other sources, however, one or both of these substances yield a distinct color change. For filtering, a piece of filter paper should be folded once through the middle and again at right angles to the first fold.

It may now be opened with one fold on one side and three on the other and fitted into a glass funnel. When the paper is folded in this manner the precipitated rosins may be readily washed with water. When the washing is completed the rosins may be dissolved by pouring alcohol through the filter. This work with the rosins will require some practice before it can be successfully performed. It is of considerable value, however, in judging of the purity of vanilla extract.

 

Lemon Extract. By lemon extract is understood a solution of lemon oil in strong alcohol. In order to contain as much lemon oil as is supposed to be found in high-grade extracts the alcohol should constitute about 80 per cent of the sample. The alcohol is therefore the most valuable constituent of lemon extract, and manufacturers who turn out a low grade product usually do so because of their economy of alcohol rather than of lemon oil. Owing to the fact that lemon extract is practically a saturated solution of oil of lemon in strong alcohol the sample may be examined by simple dilution with water. A teaspoonful of the oil in question may be placed in the bottom of an ordinary glass tumbler and 2 or 3 teaspoonfuls of water added. If the sample in question be real lemon extract the lemon oil should be thrown put of solution by reason of its insolubility in the alcohol after its dilution with water. The result is at first a marked turbidity and later the separation of the oil of lemon on the top

 


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of the aqueous liquid. If the sample remains perfectly clear after the addition of water, or if a marked turbidity is not produced, it is a low-grade product and contains very little, if any, oil of lemon.

 

Fruit Products. Adulteration of fruit products is practically confined to jellies and jams. Contrary to the general belief, gelatin is never used in making fruit jelly. In the manufacture of the very cheapest grade of jellies starch is sometimes employed. Jellies containing starch, however, are so crude in their appearance that the most superficial inspection is sufficient to demonstrate that they are not pure fruit jellies. From their appearance no one would think it worth while to examine them to determine their purity.

 

Natural fruit jellies become liquid on being warmed. A spoonful dissolves readily in warm water, although considerable time is required with those that are especially firm. The small fruits contain practically no starch, as apples do, and the presence of starch in a jelly indicates that some apple juice has probably been used in its preparation.

 

Detection of Starch. Dissolve a teaspoonful of jelly in a half teacupful of hot water, heat to boiling and add, drop by drop, while stirring with a teaspoon, a solution of potassium permanganate until the solution is almost colorless. Then allow the solution to cool and test for starch with tincture of iodine, as directed later. Artificially colored jellies are sometimes not decolorized by potassium permanganate. Even without decolorizing, however, the blue color can usually be seen.

 

Detection of Glucose. For the detection of glucose, a teaspoonful of the jelly may be dissolved in. a glass tumbler or bottle in 2 or 3 tablespoonfuls of water. The vessel in which the jelly is dissolved may be placed in hot water if necessary to hasten the solution. In case a jam or marmalade is being examined, the mixture is filtered to separate the insoluble matter. The solution is allowed to cool, and an equal volume or a little more of strong alcohol is added. If the sample is

a pure fruit product the addition of alcohol causes no precipitation, except that a very slight amount of proteid bodies is thrown down. If glucose has been employed in its manufacture, however, a dense white precipitate separates and, after a time, settles to the bottom of the liquid.

 

Detection of Foreign Seeds. In addition to the forms of adulteration to which jellies are subject, jams are sometimes manufactured from the exhausted fruit pulp left after removing the juice for making jelly. When this is done residues from different fruits are sometimes mixed. Exhausted raspberry or blackberry pulp may be used in making "strawberry" jam and vice versa. Some instances are reported of various small seeds, such as timothy, clover, and alfalfa seed, having been used with jams made from seedless pulp.

 

With the aid of a small magnifying glass such forms of adulteration may be detected, the observer familiarizing himself with the seeds of the ordinary fruits.

 

Detection of Preservatives and Colors. With jellies and jams salicylic and benzoic acids are sometimes employed. They may be detected by the methods given.

 

Artificial colors, usually coal-tar derivatives, are sometimes used and may be detected as described.

 

Meat Products. As in many other classes of foods, certain questions important in the judgment of meats require practical experience and close observation rather than chemical training. This is especially true of meat products. The general appearance of the meat must largely guide the purchaser. If, however, the meat has been treated with preservatives and coloring matter its appearance is so changed as to deceive him. The preservatives employed with meat products are boric acid, borax, and sulphites. The methods for the detection of sulphites are not suitable for household use.

 

Detection of Boric Acid and Borax.  To detect boric acid (if borax has been used the same reaction will be obtained), about a tablespoonful of the chopped meat is thoroughly macerated with a little hot water, pressed through a bag, and 2 or 3 tablespoonfuls of the liquid placed in a sauce dish with 15 or 20 drops of strong hydrochloric acid for each tablespoonful. The liquid is then filtered through filter paper, and a piece of turmeric paper dipped into it and dried near a lamp or stove. If boric acid or borax were used for preserving the sample, the turmeric paper should be changed to a bright cherry red color. If too much hydrochloric acid has been employed a dirty brownish red color is obtained, which interferes with the color due to the presence of

 


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boric acid. When a drop of household ammonia is added to the colored turmeric paper, it is turned a dark green, almost black color, if boric acid is present. If the reddish color, however, was caused by the use of too much hydrochloric acid this green color does not form.

 

Caution. The corrosive nature of hydrochloric acid must not be forgotten. It must not be allowed to touch the flesh, clothes, or any metal.

 

Detection of Colors. The detection of coloring matter in sausage is often a difficult matter without the use of a compound microscope. It may sometimes be separated, however, by macerating the meat with a mixture of equal parts of glycerine and water to which a few drops of acetic or hydrochloric acid have been added. After macerating for some time the mixture is filtered and the coloring matter detected by means of dyeing wool in the liquid thus obtained.

 

Spices. Although ground spices are very frequently adulterated, there are few methods that may be used by one who has "not had chemical training, and who is not skilled in the use of a compound microscope, for the detection of the adulterants employed. The majority of the substances used for the adulteration of spices are of a starchy character. Unfortunately for our purposes, most of the common spices also contain a considerable amount of starch. Cloves, mustard, and cayenne, however, are practically free from starch, and the presence of starch in the ground article is proof of adulteration.

 

Detection of Starch in Cloves, Mustard, and Cayenne. A half teaspoonful of the spice in question is stirred into half a cupful of boiling water, and the boiling continued for 2 or 3 minutes. The mixture is then cooled. If of a dark color, it is diluted with a sufficient amount of water to reduce the color to such an extent that the reaction formed by starch and iodine may be clearly apparent if starch be present. The amount of dilution can only be determined by practice, but usually the liquid must be diluted with an equal volume of water, or only 1/4 of a teaspoonful of the sample may be employed originally. A single drop of tincture of iodine is now added. If starch is present, a deep blue color, which in the presence of a large amount of starch appears black, is formed. If no blue color appears, the addition of the iodine tincture should be continued, drop by drop, until the liquid shows by its color the presence of iodine in solution.

 

Detection of Colors. Spice substitutes are sometimes colored with coal-tar colors. These, products may be detected by the methods given.

 

Vinegar. A person thoroughly familiar with vinegar can tell much regarding the source of the article from its appearance, color, odor, and taste.

 

If a glass be rinsed out with the sample of vinegar and allowed to stand for a number of hours or overnight, the odor of the residue remaining in the glass is quite different with different kinds of vinegar. Thus, wine vinegar has the odor characteristic of wine, and cider vinegar has a peculiar fruity odor. A small amount of practice with this test enables one to distinguish with a high degree of accuracy between wine and cider vinegars and the ordinary substitutes.

 

If a sample of vinegar be placed in a shallow dish on a warm stove or boiling teakettle and heated to a temperature sufficient for evaporation and not sufficient to burn the residue, the odor of the warm residue is also characteristic of the different kinds of vinegar. Thus, the residue from cider vinegar has the odor of baked apples and the flavor is acid and somewhat astringent in taste, and that from wine vinegar is equally characteristic. The residue obtained by evaporating vinegar made from sugarhouse products and from spirit and wood vinegar colored by means of caramel has the peculiar bitter taste characteristic of caramel.

 

If the residue be heated until it begins to burn, the odor of the burning product also varies with different kinds of vinegar. Thus, the residue from cider vinegar has the odor of scorched apples, while that of vinegars made from sugarhouse wastes and of distilled and wood vinegars colored with a large amount of caramel has the odor of burnt sugar. In noting these characteristics, however, it must be borne in mind that, in order to make them conform to these tests, distilled and wood vinegars often receive the addition of apple jelly.

 

The cheaper forms of vinegar, especially distilled and wood vinegar, are commonly colored with caramel, which can be detected by the method given.

 

FOOD COLORANTS.

 

(Most, if not all, of these colorants are injurious and should therefore be used with extreme caution.)

 

Sausage Color. To dye sausage red, certain tar dyestuffs are employed,

 


[359]

 

FOOD ADULTERANTS

 

especially the azo dyes, preference being given to the so-called genuine red. For this purpose about 100 parts of dyestuff are dissolved in 1,000 to 2,000 parts of hot water; when the solution is complete, add a likewise hot solution of 45 to 50 parts of boracic acid, whereupon the mixture should be stirred well for some time; then filter, allow to cool, and preserve in tightly closing bottles. It is absolutely necessary in using aniline colors to add a disinfectant to the dyestuff solution, the object of which is, in case the sausage should commence to decompose, to prevent the decomposition azo dyestuff by the disengaged hydrogen. Instead of boracic acid, formalin may be used as a disinfectant. Of this formalin, 38 per cent, add about 25 to

30 parts to the cooled and filtered dyestuff solution. This sausage color is used by adding about 1 1/2 to 2 tablespoonfuls of it to the preserving salt measured out for 100 kilos of sausage mass, stirring well. The sausage turns neither gray nor yellow on storing.

 

Cheese Color.

 

I.    To produce a suitable, pretty yellow color, boil 100 parts of orlean or annatto with 75 parts of potassium carbonate in 1 1/2 to 2 liters of water, allow to cool, and filter after settling, whereupon 15 to 18 parts of boracic acid are added to give keeping qualities to the solution. According to another method, digest about 200 parts of orlean. 200 parts of potassium carbonate, and 100 parts of turmeric for 10 to 12 days in 1,500 to 2,000 parts of 60 per cent alcohol, filter, and keep in bottles. To 100,000 parts of milk to be made into cheese add 1 1/2 to 2 small spoonfuls of this dye, which imparts to the cheese a permanent and natural yellow appearance.

 

II.   To obtain a handsome yellow color for cheese, such as is demanded for certain sorts, boil together 100 parts of annatto and 75 parts of potassium carbonate in from 1,500 to 2,000 parts of pure water; let it cool, stand it aside for a time, and filter, adding finally from 12 to 15 parts of boracic acid as a preservative. For coloring butter, there is in the trade a mixture of bicarbonate of soda with 12 per cent to 15 per cent of sodium chloride, to which is added from 1 1/2 per cent to 2 per cent of powdered turmeric.

 

Butter Color. For the coloring of butter there is in the market under the name of butter powder a mixture of sodium bicarbonate with 12 to 15 per cent of sodium chloride and 1 1/2 to 2 per cent of powdered turmeric; also a mixture of sodium bicarbonate, 1,500 parts; saffron surrogate, 8 parts; and salicylic acid, 2 parts. For the preparation of liquid butter color use a uniform solution of olive oil, 1,500 parts; powdered turmeric, 300 parts; orlean, 200 parts. The orlean is applied on a plate of glass or tin in a thin layer and allowed to dry perfectly, whereupon it is ground very fine and intimately mixed with the powdered turmeric. This mixture is stirred into the oil with digestion for several hours in the water bath. When a uniform, liquid mass has resulted, it is filtered hot through a linen filter with wide meshes. After cooling, the filtrate is filled into bottles. Fifty to 60 drops of this liquid color to 1 1/2 kilos of butter impart to the latter a handsome golden yellow shade.

 

INFANT FOODS:

 

Infants' (Malted) Food.

 

I.   

Powdered malt                       1 ounce

Oatmeal (finest ground)             2 ounces

Sugar of milk                       4 ounces

Baked flour                         1 pound

 

Mix thoroughly.

 

II.   Infantine is a German infant food which is stated to contain egg albumen, 5.5 per cent; fat, 0.08 per cent; water, 4.22 per cent; carbohydrates, 86.58 per cent (of which 54.08 per cent is soluble in water); and ash, 2.81 per cent (consisting of calcium, 10.11 per cent; potassium, 2.64 per cent; sodium, 25.27 per cent; chlorine, 36.65 per cent; sulphuric acid, 3.13 per cent; and phosphoric acid, 18.51 per cent).

 

MEAT PRESERVATIVES.

 

(Most of these are considered injurious by the United States Department of Agriculture and should therefore be used with extreme caution.)

 

The Preservation of Meats. Decomposition of the meat sets in as soon as the blood ceases to pulse in the veins, and it is therefore necessary to properly preserve it until the time of its consumption.

 

The nature of preservation must be governed by circumstances such as the kind and quality of the article to be preserved, length of time and climatic condition, etc. While salt, vinegar, and alcohol merit recognition on the strength of a long-continued usage as preservatives, modern usage favors boric acid and borax, and solutions containing salicylic acid and sulphuric acid are common,

 


[360]

 

FOOD PRESERVATIVES

 

 

and have been the subject of severe criticism.

 

Many other methods of preservation have been tried with variable degrees of success; and of the more thoroughly tested ones the following probably include all of those deserving more than passing mention or consideration.

 

1. The exclusion of external, atmospheric electricity, which has been observed to materially reduce the decaying of meat, milk, butter, beer, etc.

 

2. The retention of occluded electric currents. Meats from various animals packed into the same packages, and surrounded by a conducting medium, such as salt and water, liberate electricity.

 

3. The removal of the nerve centers. Carcasses with the brains and spinal cord left therein will be found more prone to decomposition than those wherefrom these organs have been removed.

 

4. Desiccation. Dried beef is an excellent example of this method of preservation. Other methods coming under this heading are the application of spices with ethereal oils, various herbs, coriander seed extracted with vinegar, etc.

 

5. Reduction of temperature, i.e., cold storage.

 

6. Expulsion of air from the meat and the containers. Appert's, Willaumez's, Redwood's, and Prof. A. Vogel's methods are representative for this category of preservation. Phenyl paper, Dr. Busch's,

Georges's, and Medlock and Baily's processes are equally well known.

 

7. The application of gases. Here may be mentioned Dr. Gamgee's and

Bert and Reynoso's processes, applying carbon dioxide and other compressed gases, respectively.

 

Air-drying, powdering of meat, smoking, pickling, sugar or vinegar curing are too well known to receive any further attention here. Whatever process may be employed, preference should be given to that which will secure the principal objects sought for, the most satisfactory being at the same time not deleterious to health, and of an easily applicable and inexpensive nature.

 

To Preserve Beef, etc., in Hot Weather. Put the meat into a hot oven and let it remain until the surface is browned all over, thus coagulating the albumen of the surface and inclosing the

body of the meat in an impermeable envelope of cooked flesh. Pour some melted lard or suet into a jar of sufficient size, and roll the latter around until the sides are evenly coated to the depth of half an inch with the material. Put in the meat, taking care that it does not touch

the sides of the jar (thus scraping away the envelope of grease), and fill up with more suet or lard, being careful to completely cover and envelop the meat. Thus prepared, the meat will remain absolutely fresh for a long time, even in the hottest weather. When required for use the outer portion may be left on or removed. The same fat may be used over and over again by melting and retaining in the melted state a few moments each time, by which means not only all solid portions of the meat which have been retained fall to the bottom, but all septic microbes are destroyed.

 

Meat Preservatives.

 

I.    Barmenite Corning Agent: For every 100 parts, by weight, take 25.2 parts, by weight, of saltpeter; 46.8 parts, by weight, sodium chloride; 25.7 parts, by weight, cane sugar; 0.8 parts, by weight, plaster of

Paris or gypsum; 0.1 part, by weight, of some moistening material, and a trace of magnesia.

 

Il.Carniform, A: For every 100 parts, by weight, take 3.5 parts, by weight, sodium diphosphate; 3.1 parts, by weight, water of crystallization; 68.4 parts, by weight, sodium chloride; 24.9 parts, by weight, saltpeter; together with traces of calcium phosphate, magnesia, and sulphuric acid.

 

III.  Carniform, B: For every 100 parts, by weight, take 22.6 parts, by weight, sodium diphosphate; 17.3 parts, by weight, water of crystallization; 59.7 parts, by weight, saltpeter; 0.6 parts, by weight, calcium phosphate; with traces of sulphuric acid and magnesia.

 

IV.   "Cervelatwurst" (spice powder): For 100 parts, by weight, take 0.7 parts, by weight, of moistening; 3.5 parts, by weight, spices mostly pepper; 89 parts, by weight, sodium chloride; 5 parts, by weight, saltpeter; 0.7 parts, by weight, gypsum; and traces of magnesia.

 

V.    Cervelatwurst Salt (spice powder): For 100 parts, by weight, take 7.5 parts, by weight, spices mostly pepper; 1.6 parts, by weight, moistener; 81.6 parts, by weight, sodium chloride; 2.5 parts, by weight, saltpeter; 6.2 parts, by weight, cane sugar; and traces of magnesia.

 

VI.   Rubrolin Sausage (spice powder): For 100 parts by weight, take 53.5 parts, by weight, sal ammoniac, and 45.2 parts, by weight, of saltpeter.

 

VII.  Servator Special Milk and Butter Preserving Salt: 80.3 per cent of crystallized boracic acid; 10.7 per cent

 


FOOD PRESERVATIVES - FOOT-POWDERS

 

[361]

 

sodium chloride; and 9.5 per cent of benzoic acid. (Its use is, however, prohibited in Germany.)

 

VIII. Wittenberg Pickling Salt: For 100 parts, by weight, take 58.6 parts, by weight, sodium chloride; 40.5 parts, by weight, saltpeter; 0.5 parts, by weight, gypsum; traces of moisture and magnesia.

 

IX.   Securo: For a quart take 3.8 parts, by weight, aluminum oxide, and 8 parts, by weight, acetic acid; basic acetate of alumina, 62 parts, by weight; sulphuric acid, 0.8 parts, by weight; sodium oxide, with substantially traces of lime and magnesia.

 

X.    Michels Cassala Salt: This is partially disintegrated. 30.74 per cent sodium chloride; 15.4 per cent sodium phosphate; 23.3 per cent potassio-sodictartrate; 16.9 per cent water of crystallization; 1.2 per cent aluminum oxide; and 2.1 per cent acetic acid as basic acetate of alumina; 8.4 per cent sugar; 0.98 per cent benzoic acid; 0.5 per cent sulphuric acid; and traces of lime.

 

XI.   Corning Salt: Sodium nitrate, 50 parts; powdered boracic acid, 45 parts; salicylic acid, 5 parts.

 

XII.  Preservative Salt: Potassium nitrate, 70 parts; sodium bicarbonate, 15 parts; sodium chloride, 15 parts.

 

XIII. Another Corning Salt: Potassium nitrate, 50 parts; sodium chloride, 20 parts; powdered boracic acid, 20 parts; sugar, 10 parts.

 

XIV.  Maciline (offered as condiment and binding agent for sausages): A mixture of wheat flour and potato flour dyed intensely yellow with an azo dyestuff and impregnated with oil of mace.

 

XV.  

Borax                               80 parts

Boric acid                          17 parts

Sodium chloride                     3 parts

 

Reduce the ingredients to a powder and mix thoroughly.

 

XVI. 

Sodium sulphite, powdered           80 parts

Sodium sulphate, powdered           20 parts

 

XVII.

Sodium chloride                     80 parts

Borax                               8 parts

Potassium nitrate                   12 parts

 

Reduce to a powder and mix.  

 

XVIII.     

Sodium nitrate                      50 parts

Salicylic acid                      5 parts

Boric acid                          45 parts

 

XIX. 

Potassium nitrate                   70 parts

Sodium bicarbonate                  15 parts

Sodium chloride                     15 parts

 

XX.  

Potassium nitrate                   50 parts

Sodium chloride                     20 parts

Boric acid                          20 parts

Sugar                               10 parts

 

A German Method of Preserving Meat. Entire unboweled cattle or large, suitably severed pieces are sprinkled with acetic acid and then packed and transported in sawdust impregnated with cooking salt and sterilized.

 

Extract of Meat Containing Albumen. In the ordinary production of meat extract, the albumen is more or less lost, partly through precipitation by the acids or the acid salts of the meat extract, partly through salting out by the salts of the extract, and partly by coagulation at a higher temperature. A subsequent addition of albumen is impracticable because the albumen is likewise precipitated, insolubly, by the acids and salts contained in the extract. This precipitation can be prevented, according to a French patent, by neutralizing the extract before mixing with albumen, by the aid of sodium bicarbonate. The drying of the mixture is accomplished in a carbonic acid atmosphere. The preparation dissolves in cold or hot water into a white, milky liquid and exhibits the smell and taste of meat extract, if the albumen added was tasteless. The taste which the extract loses by the neutralization returns in its original strength after the mixture with albumen. In this manner a meat preparation is obtained which contains larger quantities of albumen and is more nutritious and palatable than other preparations.

 

Foot-Powders and Solutions

 

The following foot-powders have been recommended as dusting powders:

 

I.   

Boric acid                          2 ounces

Zinc oleate                         1 ounce

Talcum                              3 ounces

 

II.  

Oleate of zinc (powdered)           1/2 ounce

Boric acid                          1 ounce

French chalk                        5 ounces

Starch                              1 1/2 ounces

 


[362]

 

FOOT-POWDERS - FORMALDEHYDE

 

III. 

Dried alum                          1 drachm

Salicylic acid                      1/2 drachm

Wheat starch                        4 drachms

Powdered talc                       1 1/2 ounces

 

IV.  

Formaldehyde solution               1 part

Thymol                              1/10 part

Zinc oxide                          35 parts

Powdered starch                     65 parts

 

V.   

Salicylic acid                      7 drachms

Boric acid                          2 ounces, 440 grains [?]

Talcum 3                            8 ounces

Slippery elm bark                   1 ounce

Orris root                          1 ounce

 

VI.  

Talc                                12 ounces

Boric acid                          10 ounces

Zinc oleate                         1 ounce

Salicylic acid                      1 ounce

Oil of eucalyptus                   2 drachms

 

VII. 

Salicylic acid                      7 drachms

Boric acid                          3 ounces

Talcum                              38 ounces

Slippery elm, powdered              1 ounce

Orris, powdered                     1 ounce

 

Salicylated Talcum.

 

I.   

Salicylic acid                      1 drachm

Talcum                              6 ounces

Lycopodium                          6 drachms

Starch                              3 ounces

Zinc oxide                          1 ounce

Perfume,                            quantity sufficient.

 

II.  

Tannoform                           1 drachm

Talcum                              2 drachms

Lycopodium                          30 grains

 

Use as a dusting powder.

 

Solutions for Perspiring Feet.

 

I.   

Balsam Peru                         15 minims

Formic acid                         1 drachm

Chloral hydrate                     1 drachm

Alcohol                             to make 3 ounces.

 

Apply by means of absorbent cotton.

 

II.  

Boric acid                          15 grains

Sodium borate                       6 drachms

Salicylic acid                      6 drachms

Glycerine                           1 1/2 ounces

Alcohol                             to make 3 ounces.

 

For local application.

 

FOOTSORES ON CATTLE:

See Veterinary Formulas.

 

FORMALDEHYDE:

See also Disinfectants, Foods, and Milk.

 

Commercial Formaldehyde. This extremely poisonous preservative is obtained by passing the vapors of wood spirit, in the presence of air, over copper heated to redness. The essential parts of the apparatus employed are a metal chamber into which a feed-tube enters, and from which 4 parallel copper tubes or oxidizers discharge by a common exit tube. This chamber is fitted with inspection apertures, through which the course of the process may be watched and controlled. The wood spirit, stored in a reservoir, falls into a mixer where it is volatilized and intimately mixed with air from a chamber which is connected with a force pump. The gases after traversing the oxidizer are led into a condensing coil, and the crude formaldehyde is discharged into the receiver beneath.

 

The small amount of uncondensed gas is then led through a series of two washers. The "formol" thus obtained is a mixture of water, methyl alcohol, and 30 to 40 per cent of formaldehyde. It is rectified in a still, by which the free methyl alcohol is removed and pure formol obtained, containing 40 per cent of formaldehyde, chiefly in the form of the acetal. Rectification must not be pushed too far, otherwise the formaldehyde may become polymerized into trioxmethylene. When once oxidation starts, the heat generated is sufficient to keep the oxidizers red hot, so that the process works practically automatically.

 

Determination of the Presence of Fomaldehyde in Solutions. Lemme makes use, for this purpose, of the fact that formaldehyde, in neutral solutions of sodium sulphite, forms normal bisulphite salts, setting free a corresponding quantity of sodium hydrate, that may be titrated with sulphuric acid and phenolphthalein. The sodium sulphite solution has an alkaline reaction toward phenolphthalein, and must be exactly neutralized with sodium bisulphite. Then to 100 cubic centimeters of this solution of 250 grams of sodium sulphite (Na2SO3 +7H2O) in 750 grams water, add 5 cubic centimeters of the suspected formaldehyde solution. A strong red color is instantly produced. Titrate with normal sulphuric acid until the color disappears. As the exact disappearance of the color is not easily determined, a margin of from 0.1 to 0.2 cubic centimeters may be allowed without the exactness of the reaction being injured, since 1 cubic centimeter of normal acid answers to only 0.03 grams of formaldehyde.

 

FORMALIN FOR GRAIN SMUT:

See Grain.

 


[363]

 

FREEZING PREVENTIVES - FROST BITE

 

FRAMES: THEIR PROTECTION FROM FLIES.

 

Since there is great risk of damaging the gilt when trying to remove flyspecks with spirits of wine, it has been found serviceable to cover gilding with a copal varnish. This hardens and will stand rough treatment, and may be renewed wherever removed.

 

FRAME CLEANING:

See Cleaning Preparations and Methods.

 

FRAME POLISHES:

See Polishes.

 

FRAMING, PASSE-PARTOUT:

See Passe-Partout.

 

FRECKLE LOTIONS:

See Cosmetics.

 

FREEZING MIXTURES:

See also Refrigeration and Refrigerants.

 

Freezing Preventives

 

Liquid for Cooling Automobile Engines. In order to prevent freezing of the jacket water, when the engine is not in operation in cold weather, solutions are used, notably of glycerine and of calcium chloride (CaCl2). The proportions for the former solution are equal parts of water and glycerine, by weight; for the latter, approximately 1/2 gallon of water to 8 pounds of CaCl2, or a saturated solution at 60║ F. This solution (CaCl2 + 6H2O) is then mixed with equal parts of water, gallon for gallon. Many persons complain that CaCl2 corrodes the metal parts, but this warning need do no more than urge the automobilist to use only the chemically pure salt, carefully avoiding the "chloride of lime" (CaOCl2).

 

A practical manufacturing chemist of wide experience gives this:

 

A saturated solution of common salt is one of the best things to use. It does not affect the metal of the engine, as many other salts would, and is easily renewed. It will remain fluid down to 0║ F., or a little below.

 

Equal parts of glycerine and water is also good, and has the advantage that it will not crystallize in the chambers, or evaporate readily. It is the most convenient solution to use on this account, and may repay the increased cost over brine, in the comfort of its use. It needs only the occasional addition of a little water to make it last all winter and leave the machinery clean when it is drawn off. With brine an incrustation of salt as the water evaporates is bound to occur which reduces the efficiency of the solution until it is removed. Water frequently must be added to keep the original volume, and to hold the salt in solution. A solution of calcium chloride is less troublesome so far as crystallizing is concerned, but is said to have a tendency to corrode the metals.

 

Anti-Freezing Solution for Automobilists. Mix and filter 4 1/2 pounds pure calcium chloride and a gallon of warm water and put the solution in the radiator or tank. Replace evaporation with clean water, and leakage with solution. Pure calcium chloride retails at about 8 cents per pound, or can be procured from any wholesale drug store at 5 cents.

 

Anti-Freezing, Non-Corrosive Solution. A solution for water-jackets on gas engines that will not freeze at any temperature above 20║ below zero (F.) may be made by combining 100 parts of water, by weight, with 75 parts of carbonate potash and 50 parts of glycerine. This solution is non-corrosive and will remain perfectly liquid at all temperatures above its congealing point.

 

Anti-Frost Solution. As an excellent remedy against the freezing of shop windows, apply a mixture consisting of 55 parts of glycerine dissolved in 1,000 parts of 62 per cent alcohol, containing, to improve the odor, some oil of amber. As soon as the mixture clarifies, it is rubbed over the inner surface of the glass. This treatment, it is claimed, not only prevents the formation of frost, but also stops sweating.

 

Protection of Acetylene Apparatus from Frost. Alcohol, glycerine, and calcium chloride have been recommended for the protection of acetylene generators from frost. The employment of calcium chloride, which must not be confounded with chloride of lime, appears preferable in all points of view. A solution of 20 parts of calcium chloride in 80 parts of water congeals only at 5║ F. above zero. But as this temperature does not generally penetrate the generators, it will answer to use 10 or 15 parts of the chloride for 100 parts of water, which will almost always be sufficient to avoid congelation. Care must be taken not to use sea salt or other alkaline or metallic salts, which deteriorate the metal of the apparatus.

 

FROST BITE.

 

When the skin is as yet unbroken, Hugo Kuhl advises the following:

 


[364]

 

FROST BITE - FRUIT PRESERVING

 

I.   

Carbolized water                    4 drachms

Nitric acid                         1 drop

Oil of geranium                     1 drop

 

Mix.  Pencil over the skin and then hold the penciled place near the fire until the skin is quite dry.

 

If the skin is already broken, use the following ointment:

 

II.  

Hebra's ointment                    500 parts

Glycerine                           100 parts

Liquefied carbolic acid             15 parts

 

Mix.  Apply to the broken skin occasionally.

 

III. 

Camphor                             25 parts

Iodine, pure                        50 parts

Olive oil                           500 parts

Paraffine, solid                    450 parts

Alcohol,                            enough.

 

Dissolve the camphor in the oil and the iodine in the least possible amount of alcohol. Melt the paraffine and add the mixed solutions. When homogeneous pour into suitable molds. Wrap the pencils in paraifine paper or tin foil, and pack in wooden boxes. By using more or less olive oil the pencils may be made of any desired consistency.

 

IV.   Dissolve 5 parts of camphor in a mixture consisting of 5 parts of ether and 5 parts of alcohol; then add collodion sufficient to make 100 parts.

 

V.    Dissolve 1 part of thymol in 5 parts of a mixture of ether and alcohol, then add collodion sufficient to make 100 parts.

 

VI.  

Carbolic aid                        2 parts

Lead ointment                       40 parts

Lanolin                             40 parts

Olive oil                           20 parts

Lavender oil                        1 1/2 parts

 

VII. 

Tannic acid                         15 parts

Lycopodium                          15 parts

Lard                                30 parts

 

VIII.

Zinc oxide                          15 parts

Glycerine                           45 parts

Lanolin                             40 parts

 

IX.  

Ichthyol                            10 parts

Resorcin                            10 parts

Tannic acid                         10 parts

Distilled water                     50 parts

 

Any of these is to be applied about twice a day.

 

FROSTED GLASS:

See Glass.

 

FROST PREVENTIVE:

See Freezing Preventives.

 

FROST REMOVERS:

See Glass.

 

FRUIT ESSENCES AND EXTRACTS:

See Essences and Extracts.

 

Fruit Preserving

(See also Essences, Extracts, and Preserves.)

 

How to Keep Fruit. According to experiments of Max de Nansouty, fruit carefully wrapped in silk paper and then buried in dry sand will preserve a fresh appearance with a fresh odor or flavor, almost indefinitely. It may also be preserved in dry excelsior, but not nearly so well. In stubble or straw fruit rots very quickly, while in shavings it. mildews quickly. In short, wheat-straw fruit often takes on a musty taste and odor, even when perfectly dry. Finally, when placed on wooden tablets and exposed to the air, most fruit decays rapidly.

 

I.    Crushed Strawberry. Put up by the following process, the fruit retains its natural color and taste, and may be exposed to the air for months, without fermenting:

 

Take fresh, ripe berries, stem them, and rub through a No. 8 sieve, rejecting all soft and green fruit. Add to each gallon of pulp thus obtained, 8 pounds of granulated sugar. Put on the fire and bring just to a boil, stirring constantly. Just before removing from the fire, add to each gallon 1 ounce of a saturated alcoholic solution of salicylic acid, stirring well. Remove the scum, and, while still hot, put into jars, and hermetically seal. Put the jars in cold water, and raise them to the boiling point, to prevent them from bursting by sudden expansion on pouring hot fruit into them. Fill the jars entirely full, so as to leave no air space when fruit cools and contracts.

 

II.   Crushed Raspberry. Prepare in the same manner as for crushed strawberry, using 1/2 red raspberries and 1/2 black, to give a nice color, and using 7 pounds of sugar to each gallon of pulp.

 

III.  Crushed Pineapple. Secure a good brand of canned grated pineapple, and drain off about one-half of the liquor, by placing on a strainer. Add to each pound of pineapple 1 pound of granulated sugar. Place on the fire, and bring to boiling point, stirring constantly. Just before removing from the fire, add to each gallon of pulp 1 ounce saturated alcoholic solution of salicylic acid.

 


[365]

 

FRUIT PRESERVING - FUMIGANTS

 

Put into air-tight jars until wanted for use.

 

IV.   Crushed Peach. Take a good brand of canned yellow peaches, drain off liquor, and rub through a No. 8 sieve. Add sugar, bring to the boiling point, and when ready to remove from fire add to each gallon 1 ounce saturated alcoholic solution of salicylic acid. Put into jars and seal hermetically.

 

V.    Crushed Apricot. Prepared in similar manner to crushed peach, using canned apricots.

 

VI.   Crushed Orange. Secure oranges with a thin peel, and containing plenty of juice. Remove the outer, or yellow peel, first, taking care not to include any of the bitter peel. (The outer peel may be used in making orange phosphate, or tincture of sweet orange peel.) Next remove the inner, bitter peel, quarter, and remove the seeds. Extract part of the juice, and grind the pulp through an ordinary meat grinder. Add sugar, place on the fire, and bring to the boiling point. When ready to remove, add to each gallon 1 ounce of saturated alcoholic solution of salicylic acid and 1 ounce of glycerine. Put into air-tight jars.

 

VII.  Crushed Cherries. Stone the cherries and grind them to a pulp. Add sugar, and place on the fire, stirring constantly. Before removing, add to each gallon 1 ounce of the saturated solution of salicylic acid. Put into jars and seal.

 

VIII. Fresh Crushed Fruits in Season. In their various seasons berries and fruits may be prepared in fresh lots for the soda fountain each morning, by reducing the fruit to a pulp, and mixing this pulp with an equal quantity of heavy simple syrup.

 

Berries should be rubbed through a sieve. In selecting berries, it is better to use the medium-sized berries for the pulp, reserving the extra large specimens for garnishing and decorative effects.

 

Mash the berries with a wooden masher, never using iron or copper utensils, which may discolor the fruit.

 

Pineapple may be prepared by removing the rough outer skin and grating the pulp upon an ordinary tin kitchen grater. The grater should be scrupulously clean, and care should be taken not to grate off any of the coarse, fibrous matter comprising the fruit's core.

 

All crushed fruits are served as follows: Mix equal quantities of pulp and simple syrup in the counter bowl; use 1 1/2 to 2 ounces to each glass, adding the usual quantity of cream, or ice cream. Draw soda, using a fine stream freely.

 

IX.   GlacÚs. Crushed fruits, served in the following manner, make a delicious and refreshing drink:

 

Crushed fruit. 12 drachms

Juice of half a lemon.

Shaved ice.

 

Put the ice into a small glass, add the fruit and lemon juice, stir well, and serve with a spoon and straws.

 

FRUIT PRODUCTS, TESTS FOR:

See Foods.

 

FRUIT SYRUPS:

See Syrups.

 

FRUIT VINEGAR:

See Vinegar.

 

Fumigants

(See also Disinfectants.)

 

Fumigating Candles.

 

I.    Lime wood charcoal, 6,000 parts, by weight, saturated with water (containing saltpeter, 150 parts, by weight, in solution), and dried again, is mixed with benzoin, 750 parts, by weight; styrax, 700 parts, by weight; mastic, 100 parts, by weight; cascarilla, 450 parts, by weight; Peruvian balsam, 40 parts, by weight; Mitcham oil, lavender oil, lemon oil, and bergamot oil, 15 parts, by weight, each; and neroli oil, 3 parts, by weight.

 

II.   Charcoal, 7,500 parts, by weight; saltpeter, 150 parts, by weight; Tolu balsam, 500 parts, by weight; musk, 2 parts, by weight; rose oil, 1 part. The mixtures are crushed with thick tragacanth to a solid mass.

 

III.  Sandal wood, 48 parts, by weight; clove, 6 parts, by weight; benzoin, 6 parts, by weight; licorice juice, 4 parts, by weight; potash saltpeter, 2 parts, by weight ; cascarilla bark, 1.5 parts, by weight; cinnamon bark, 1.5 parts, by weight; musk, 0.05 parts, by weight.

All these substances are powdered and mixed, whereupon the following are added: Styrax (liquid), 5 parts, by weight; cinnamon oil, 0.05 parts, by weight; clove oil, 0.05 parts, by weight; geranium oil,

0.5 parts, by weight; lavender oil, 0.2 parts, by weight; Peruvian balsam, 0.2 parts, by weight. The solid ingredients are each powdered separately, then placed in the respective proportion in a

 


[366]

 

FUMIGANTS

 

spacious porcelain dish and intimately mixed by means of a flat spatula. The dish must be covered up with a cloth in this operation. After the mixture has been accomplished, add the essential oils and just enough solution of gum arabic so that by subsequent kneading with the pestle a moldable dough results which possesses sufficient solidity after drying. The mass is pressed into metallic molds in the shape of cones not more than 3/4 of an inch in height.

 

IV.   Red Fumigating Candles. Sandal wood, 1 part; gum benzoin, 1.5 parts; Tolu balsam, 0.250 parts; sandal oil, .025 parts; cassia oil, .025 parts; clove oil, 25 parts; saltpeter, .090 parts. The powder is mixed intimately, saturated with spirit of wine, in which the oils are dissolved, and shaped into cones.

 

V.   

Wintergreen oil                     1 part

Tragacanth                          20 parts

Saltpeter                           50 parts

Phenol, crystallized                100 parts

Charcoal, powdered                  830 parts

Water

 

Dissolve the saltpeter in the water, stir the solution together with the powdered charcoal and dry. Then add the tragacanth powder, also the wintergreen oil and the phenol, and prepare from the mixture, by means of a tragacanth solution containing 2 per cent of saltpeter, a mass which can be shaped into candles.

 

Fumigating Perfumes. These are used for quickly putting down bad odors in the sick room, etc. They are decidedly antiseptic, and fulfil their purpose admirably.

 

I.    Select good white blotting paper, and cut each large sheet lengthwise into 3 equal pieces. Make a solution of 1 ounce of potassium nitrate in 12 ounces of boiling water; place this solution in a large plate, and draw each strip of paper over the solution so as to saturate it. Then dry by hanging up. The dried paper is to be saturated in a similar manner with either of the following solutions:

 

(1)

Siam benzoin                        1 ounce

Storax                              3 drachms

Olibanum                            2 scruples

Mastic                              2 scruples

Cascarilla                          2 drachms

Vanilla                             1 drachm

Rectified spirit                    8 ounces

 

Bruise the solids and macerate in the spirit 5 days, filter, and add

 

Oil of cinnamon                     8 parts

Oil of cloves                       8 parts

Oil of bergamot                     5 parts

Oil of neroli                       5 parts

 

Mix. 

 

(2)

Benzoin                             1 1/2 ounces

Sandal wood                         1 ounce

Spirit                              8 ounces

 

Macerate as No. 1, and add

 

Essence of vetiver                  3 ounces

Oil of lemon grass                  40 drops

 

Mix. 

 

After the paper is dry, cut up into suitable sized pieces to go into commercial envelopes.

 

II.  

Benzoin                             1 av. ounce

Storax                              1 av. ounce

Fumigating essence                  2 fluidounces

Ether                               1 fluidounce

Acetic acid, glacial                20 drops

Alcohol                             2 fluidounces

 

Dissolve the benzoin and storax in a mixture of the alcohol and ether, filter and add the fumigating and the acetic acid. Spread the mixture upon filtering or bibulous paper and allow it to dry. To prevent sticking, dust the surface with talcum and preserve in wax paper. When used the paper is simply warmed, or held over a lamp.

 

III. 

Musk                                0.2 parts

Oil of rose                         1 part

Benzoin                             100 parts

Myrrh                               12 parts

Orris root                          250 parts

Alcohol (90 per cent)               500 parts

 

IV.  

Benzoin                             80 parts

Balsam Tolu                         20 parts

Storax                              20 parts

Sandal wood                         20 parts

Myrrh                               10 parts

Cascarilla bark                     20 parts

Musk                                0.2 parts

Alcohol                             250 parts

 

Fumigating Ribbon.

 

I.    Take 1/2 inch cotton tape and saturate it with niter; when dry, saturate with the following tincture:

 

Benzoin                             1 ounce

Orris root                          1 ounce

Myrrh                               2 drachms

Tolu balsam                         2 drachms

Musk                                10 grains

Rectified spirit                    10 ounces

 

Macerate for a week, filter, and add

 

10 minims of attar of rose.

 

II.   Another good formula which may also be used for fumigating paper, is:

 


[367]

 

FUMIGANTS

 

Olibanum                            2 ounces

Storax                              1 ounce

Benzoin                             6 drachms

Peruvian balsam                     1/2 ounce

Tolu balsam                         3 drachms

Rectified spirit                    10 ounces

 

Macerate 10 days, and filter.

 

Perfumed Fumigating Pastilles.

 

I.   

Vegetable charcoal                  6 ounces

Benzoin                             1 ounce

Nitrate of potash                   1/2 ounce

Tolu balsam                         2 drachms

Sandal wood                         2 drachms

Mucilage of tragacanth,             a sufficiency.

 

Reduce the solids to fine powder, mix, and make into a stiff paste with the mucilage. Divide this into cones 25 grains in weight, and dry with a gentle heat.

 

II.  

Powdered willow charcoal            8 ounces

Benzoic acid                        6 ounces

Nitrate of potash                   6 drachms

Oil of thyme                        1/2 drachm

Oil of sandal wood                  1/2 drachm

Oil of caraway                      1/2 drachm

Oil of cloves                       1/2 drachm

Oil of lavender                     1/2 drachm

Oil of rose                         1/2 drachm

Rose water                          10 ounces

 

Proceed as in I, but this recipe is better for the addition of 20 grains of powdered tragacanth.

 

III. 

Benzoin                             10 av. ounces

Charcoal                            24 av. ounces

Potassium nitrate                   1 av. ounce

Sassafras                           2 av. ounces

Mucilage of acacia,                 sufficient.

 

Mix the first four in fine powder, add the mucilage, form a mass, and make into conical pastilles.

 

IV.  

Potassium nitrate                   375 grains

Water                               25 fluidounces

Charcoal wood, powder               30 av. ounces

Tragacanth, powder                  375 grains

Storax                              300 grains

Benzoin                             300 grains

Vanillin                            8 grains

Coumarin                            3 grains

Musk                                3 grains

Civet                               1 1/2 grains

Oil of rose                         20 drops

Oil of bergamot                     15 drops

Oil of ylang-ylang                  10 drops

Oil of rhodium                      10 drops

Oil of sandal wood                  5 drops

Oil of cinnamon                     5 drops

Oil of orris                        1 drops

Oil of cascarilla                   1 drops

 

Saturate the charcoal with the potassium nitrate dissolved in the water, dry the mass, powder, add the other ingredients, and mix thoroughly. Beat the mixture to a plastic mass with the addition of sufficient mucilage of tragacanth containing 2 per cent of saltpeter in solution, and form into cone-shaped pastilles. In order to evenly distribute the storax throughout the mass, it may be previously dissolved in a small amount of acetic ether.

 

V.   

Benzoin                             2 av. ounces

Cascarilla                          1 av. ounce

Myrrh                               1 av. ounce

Potassium nitrate                   1/2 av. ounce

Potassium chlorate                  60 grains

Charcoal, wood                      4 av. ounces

Oil of cloves                       1 fluidrachm

Oil of cinnamon                     1 fluidrachm

Oil of lavender                     1 fluidrachm

Mucilage of tragacanth,             sufficient.

 

Mix the first six ingredients previously reduced to fine powder, add the oils, and then incorporate enough mucilage to form a mass. Divide this into pastilles weighing about 60 grains and dry.

 

VI.  

Charcoal, powder                    30 av. ounces

Potassium nitrate                   1/2 av. ounce

Water                               33 fluidounces

Tragacanth, powder                  300 grains

Tincture of benzoin                 1 1/2 fluidounces

Peru balsam                         300 grains

Storax, crude                       300 grains

Tolu balsam                         300 grains

Oleo-balsamic mixture               2 1/2 fluidrachms

Coumarin                            8 grains

 

Saturate the charcoal with the potassium nitrate dissolved in the water, then dry, reduce to powder, and incorporate the tragacanth and then the remaining ingredients. Form a mass by the addition of sufficient mucilage of tragacanth containing 2 per cent of potassium nitrate in solution and divide into pastilles.

 

VII. 

Powdered nitrate of potassium       1/2 ounce

Powdered gum arabic                 1/2 ounce

Powdered cascarilla bark (fresh)    1/2 ounce

Powdered benzoin (fresh)            4 ounces

 


[368]

 

FURS - GARDENS, CHEMICAL

 

Powdered charcoal                   7 ounces

Oil of eucalyptus                   25 drops

Oil of cloves                       25 drops

Water,                              a sufficiency.

 

Make a smooth paste, press into molds and dry.

 

FURS:

 

To Clean Furs. For dark furs, warm a quantity of new bran in a pan, taking care that it does not burn, to prevent which it must be briskly stirred. When well warmed rub it thoroughly into the fur with the hand. Repeat this 2 or 3 times, then shake the fur, and give it another sharp rubbing until free from dust. For white furs: Lay them on a table, and rub well with bran made moist with warm water; rub until quite dry, and afterwards with dry bran. The wet bran should be put on with flannel, then dry with book muslin. Light furs, in addition to the above, should be well rubbed with magnesia or a piece of book muslin, after the bran process, against the way of the fur.

 

To Preserve Furs.

 

I.    Furs may be preserved from moths and other insects by placing a little colocynth pulp (bitter apple), or spice (cloves, pimento, etc.), wrapped in muslin, among them; or they may be washed in a very weak solution of corrosive sublimate in warm water (10 to 15 grains to the pint), and afterwards carefully dried. As well as every other species of clothing, they should be kept in a clean, dry place, from which they should be taken out occasionally, well beaten, exposed to the air, and returned.

 

II.   Sprinkle the furs or woolen stuffs, as well as the drawers or boxes in which they are kept, with spirits of turpentine, the unpleasant scent of which will speedily evaporate on exposure of the stuffs to the air. Some persons place sheets of paper moistened with spirits of turpentine, over, under, or between pieces of cloth, etc., and find it a very effectual method. Many woolen drapers put bits of camphor, the size of a nutmeg, in papers, on different parts of the shelves in their shops, and as they brush their cloths every 2, 3, or 4 months, this keeps them free from moths; and this should be done in boxes where the furs, etc., are put. A tallow candle is frequently put within each muff when laid by. Snuff or pepper is also good.

 

FURNACE JACKET.

 

A piece of asbestos millboard - 10 inches by 4 inches by 3/8 inch - is perforated in about a dozen or more places with glycerined cork borers, then nicked about an inch from each short end and immersed in water until saturated; next the board is bent from the nicks at right angles and the perforated portion shaped by bending it over a bottle with as little force as possible. The result should be a perforated arched tunnel, resting on narrow horizontal ledges at each side. Dry this cover in the furnace, after setting it in position, and pressing it well to the supports. Three such covers, weighing 1 pound, replaced 24 fire clay tiles, weighing 13 pounds, and a higher temperature was obtained than with the latter.

 

FURNITURE CLEANERS:

See Cleaning Preparations and Methods.

 

FURNITURE, ITS DECORATION:

See Wood.

 

FURNITURE ENAMEL:

See Varnishes.

 

FURNITURE POLISHES:

See Polishes.

 

FURNITURE WAX:

See Waxes.

 

FUSES:

See Pyrotechnics.

 

FUSES FOR ELECTRICAL CIRCUITS:

See Alloys.

 

FUNNELS, TO CLEAN:

See Cleaning Preparations and Methods.

 

GALVANIZED PAPER:

See Paper, Metallic.

 

GAMBOGE STAIN:

See Lacquers.

 

GAPES IN POULTRY:

See Veterinary Formulas.

 

GARANCINE PROCESS:

See Dyes.

 

GARDENS, CHEMICAL:

See also Sponges.

 

I.    Put some sand into a fish-globe or other suitable glass vessel to the depth of 2 or 3 inches; in this place a few pieces of sulphate of copper, aluminum, and iron; pour over the whole a solution of sodium silicate (water glass), 1 part, and water, 3 parts, care being taken not to disarrange the chemicals. Let this stand a week or so, when a dense growth of the silicates of the various bases used will be seen in various colors. Now displace

 


[369]

 

GARDENS, CHEMICAL - GELATIN

 

the solution of the sodium silicate with clear water, by conveying a stream of water through a very small rubber tube into the vessel. The water will gradually displace the sodium silicate solution. Care must be taken not to disarrange or break down the growth with the stream of water. A little experimenting, experience and expertness will enable the operator to produce a very pretty garden.

 

II.   This is a permanent chemical garden, which may be suspended by brass chains with a lamp behind.

 

Prepare a small beaker or jar full of cold saturated solution of Glauber's salt, and into the solution suspend by means of threads a kidney bean and a non-porous body, such as a marble, stone, glass, etc. Cover the jar, and in a short time there will be seen radiating from the bean small crystals of sulphate of sodium which will increase and give the bean the aspect of a sea urchin, while the nonporous body remains untouched. The bean appears to have a special partiality for the crystals, which is due to the absorption of water by the bean, but not of the salt. In this way a supersaturated solution is formed in the immediate neighborhood of the bean, and the crystals, in forming, attach themselves to its surface.

 

III.  A popular form of ornamental crystallization is that obtained by immersing a zinc rod in a solution of a lead salt, thus obtaining the "lead tree." To prepare this, dissolve lead acetate in water, add a few drops of nitric acid, and then suspend the zinc rod in the solution.

The lead is precipitated in large and beautiful plates until the solution is exhausted or the zinc dissolved. In this case the action is electro-chemical, the first portions of the lead precipitated forming with the zinc a voltaic arrangement of sufficient power to decompose the salt.

 

It is said that by substituting chloride of tin for the lead salt a "tin tree" may be produced, while nitrate of silver under the same conditions would produce a "silver tree." In the latter case distilled water should be used to prevent precipitation of the silver by possible impurities contained in ordinary water.

 

GAS FIXTURES:

See Brass.

 

GAS FIXTURES, BRONZING OF:

See Plating.

 

GAS SOLDERING:

See Soldering.

 

GAS-STOVES, TO CLEAN:

See Cleaning Preparations and Methods.

 

GAS TRICK:

See Pyrotechnics.

 

GEAR LUBRICANT:

See Lubricants.

 

GELATIN:

 

French Gelatin. Gelatin is derived from two sources, the parings of skins, hides, etc., and from bones. The latter are submitted to the action of dilute hydrochloric acid for several days, which attacks the inorganic matters carbonates, phosphates, etc., and leaves the ossein, which is, so to say, an isomer of the skin substance. The skin, parings of hide, etc., gathered from the shambles, butcher shops, etc., are brought into the factory, and if not ready for immediate use are thrown into quicklime, which preserves them for the time being. From the lime, after washing, they pass into dilute acid, which removes the last traces of lime, and are now ready for the treatment that is to furnish the pure gelatin. The ossein from bones goes through the same stages of treatment, into lime, washed and laid in dilute acid again. From the acid bath the material goes into baths of water maintained at a temperature not higher than from 175║ to 195║ F.

 

The gelatin manufacturer buys from the button-makers and manufacturers

of knife handles and bone articles generally, those parts of the bone that they cannot use, some of which are pieces 8 inches long by a half inch thick.

 

Bones gathered by the ragpickers furnish the strongest glue. The parings of skin, hide, etc., are from those portions of bullock hides, calf skins, etc., that cannot be made use of by the tanner, the heads, legs, etc.

 

The gelatin made by Coignet for the Pharmacie Centrale de France is made from skins procured from the tawers of Paris, who get it directly from the abattoirs, which is as much as to say that the material is guaranteed fresh and healthy, since these institutions are under rigid inspection and surveillance of government inspectors and medical men.

 

There is a gelatin or glue, used exclusively for joiners, inside carpenters, and ceiling makers (plafonneurs), called rabbit vermicelli, and derived from rabbit skins. As the first treatment of these skins is to saturate them with mercury bichloride, it is needless to say the product is not employed in pharmacy.

 


[370]

 

GELATIN - GEMS

 

To Clarify Solutions of Gelatin, Glues, etc. If 1 per cent of ammonium fluoride be added to turbid solutions of gelatin or common glue, or, in fact, of any gums, it quickly clarifies them. It causes a deposition of ligneous matter, and also very materially increases the adhesive power of such solutions.

 

Air Bubbles in Gelatin. The presence of minute air bubbles in cakes of commercial gelatin often imparts to them an unpleasant cloudy appearance. These minute air bubbles are the result of the rapid, continuous process of drying the sheets of gelatin by a counter-current of hot air. Owing to the rapid drying a hard skin is formed on the outside of the cake, leaving a central layer from which the moisture escapes only with difficulty, and in which the air bubbles remain behind. Since the best qualities of gelatin dry most rapidly, the presence of these minute bubbles is, to a certain extent, an indication of superiority, and they rarely occur in the poorer qualities of gelatin. If dried slowly in the old way gelatin is liable to be damaged by fermentation; in such cases large bubbles of gas are formed in the sheets, and are a sign of bad quality.

 

GEMS, ARTIFICIAL:

See also Diamonds.

 

The raw materials for the production of artificial gems are the finest silica and, as a rule, finely ground rock crystals; white sand and quartz, which remain pure white even at a higher temperature, may also be used. 

 

Artificial borax is given the preference, since the native variety frequently contains substances which color the glass. Lead carbonate or red lead must be perfectly pure and not contain any protoxide, since the latter gives the glass a dull, greenish hue. White lead and red lead have to dissolve completely in dilute nitric acid or without leaving a residue; the solution, neutralized as much as possible, must not be reddened by prussiate of potash. In the former case tin is present, in the latter copper. Arsenious acid and saltpeter must be perfectly pure; they serve for the destruction of the organic substances. The materials, without the coloring oxide, furnish the starting quantity for the production of artificial gems; such glass pastes are named "strass."

 

The emerald, a precious stone of green color, is imitated by melting 1,000 parts of strass and 8 parts of chromic oxide. Artificial emeralds are also obtained with cupric acid and ferric oxides, consisting of 43.84 parts of rock crystal; 21.92 parts of dry sodium carbonate; 7.2 parts of calcined and powdered borax; 7.2 parts of red lead; 3.65 parts of saltpeter; 1.21 parts of red ferric oxide, and 0.6 parts of green copper carbonate.

 

Agates are imitated by allowing fragments of variously colored pastes to flow together, and stirring during the deliquatiorI.  

 

The amethyst is imitated by mixing 300 parts of a glass frit with 0.6 parts of gray manganese ore, or from 300 parts of frit containing 0.8 per cent of manganic oxide, 36.5 parts of saltpeter, 15 parts of borax, and 15 parts of minium (red lead). A handsome amethyst is obtained by melting together 1,000 parts of strass, 8 parts of manganese oxide, 5 parts of cobalt oxide, and 2 parts of gold purple.

 

Latterly, attempts have also been made to produce very hard glasses for imitation stones from alumina and borax with the requisite coloring agents.

 

Besides imitation stones there are also produced opaque glass pastes bearing the name of the stones they resemble, e.g., aventurine, azure stone (lapis lazuli), chrysoprase, turquoise, obsidian, etc. For these, especially pure materials, as belonging to the most important ingredients of glassy bodies, are used, and certain quantities of red lead and borax are also added.

 

GEM CEMENTS:

See Adhesives, under Jewelers' Cements.

 

GERMAN SILVER:

See Alloys.

 

GERMAN SILVER SOLDERS:

See Solders.

 

GILDING:

See Paints, Plating, and Varnishes.

 

GILDING GLASS:

See Glass.

 

GILDING, TO CLEAN:

See Cleaning Preparations and Methods.

 

GILDING, RENOVATION OF:

See Cleaning Compounds.

 

GILDING SUBSTITUTE:

See Plating.

 

GILT, TEST FOR:

See Gold.

 

GILT WORK, TO BURNISH:

See Gold.

 


[371]

 

GLASS

 

GINGERADE:

See Beverages.

 

GINGER ALE AND GINGER BEER:

See Beverages.

 

GINGER CORDIAL:

See Wines and Liquors.

 

GINGER EXTRACTS:

See Essences and Extracts.

 

Glass

 

Bent Glass. This was formerly used for show cases; its use in store fronts is becoming more and more familiar, large plates being bent for this purpose. It is much used in the construction of dwellings, in windows, or rounded corners, and in towers; in coach fronts and in rounded front china closets. Either plain glass or beveled glass may be bent, and to any curve.

 

The number of molds required in a glass-bending establishment is large.

 

The bending is done in a kiln. Glass melts at 2,300║ F.; the heat employed in bending is 1,800║ F. No pyrometer would stand long in that heat, so the heat of the kiln is judged from the color of the flame and other indications. Smaller pieces of glass are put into the molds in the kilns with forks made for the purpose. The great molds used for bending large sheets of glass are mounted on cars, that may be rolled in and out of kilns. The glass is laid upon the top of the mold or cavity, and is bent by its own weight. As it is softened by the heat it sinks into the mold and so is bent. It may take an hour or two to bend the glass, which is then left in the kiln from 24 to 36 hours to anneal and cool. Glass of any kind or size is put into the kilns in its finished state; the great heat to which it is subjected does not disturb the polished surface. Despite every precaution more or less glass is broken in bending. Bent glass costs about 50 per cent more than the flat.

 

The use of bent glass is increasing, and there are 4 or 5 glass-bending establishments in the United States, of which one is in the East.

 

Colored Glass. R. Zsigmondy has made some interesting experiments in coloring glass with metallic sulphides, such as molybdenite, and sulphides of antimony, copper, bismuth, and nickel. Tests made with batches of 20 to 40 pounds and with a heat not too great, give good results as follows:

 

Sand, 65 parts; potash, 15 parts; soda, 5 parts; lime, 9 parts; molybdenite, 3 parts; sulphide of sodium, 2 parts, gave a dark reddish-brown glass. In thinner layers this glass appeared light brownish yellow. Flashed with opal, it became a smutty black brown.

 

Sand, 50 parts; potash, 15 parts; soda, 5 parts; lime, 9 parts; molybdenite, 1 part; sulphide of sodium, 2 parts, gave a yellow

glass.

 

Sand, 10 parts; potash, 3. 3 parts; soda, 0.27 parts; lime, 1.64 parts; molybdenite, 0.03 parts, gave a reddish-yellow glass with a fine tinge of red.

 

Sand, 100 parts; potash, 26 parts; soda, 108 parts; lime, 12 parts; sulphide of copper, 1.7 parts; sulphide of sodium, 2.3 parts, gave a dark-brown color, varying from sepia to sienna. In thick layers it was no longer transparent, but still clear and unclouded. When heated this glass became smutty black brown and clouded.

 

A fine copper red was obtained from sand, 10 parts; potash, 3 parts; lime, 1.2 parts; soda, 0.25 parts; sulphide of copper, 7.5 parts; sulphide of sodium, 10.5 parts; borax, 9.5 parts.

 

Attempts to color with sulphides of antimony and bismuth failed. But the addition of 7 per cent of sulphide of nickel to an ordinary batch gave a glass of fine amethyst color.

 

Coloring Electric-Light Bulbs and Globes. Two substances suggest themselves as excellent vehicles of color, and both water soluble water glass (potassium or sodium silicate) and gelatin. For tinting, water-soluble aniline colors should be tried. The thickness of the solution must be a matter of experimentation. Prior to dipping the globes they should be made as free as possible from all grease, dirt, etc. The gelatin solution should not be so thick that any appreciable layer of it will form on the surface of the glass, and to prevent cracking, some non-drying material should be added to it, say glycerine.

 

Rose-Tint Glass. Selenium is now used for coloring glass. Rose-tinted glass is made by adding selenium directly to the ingredients in the melting pot. By mixing first with cadmium sulphide, orange red is produced. This process is stated not to require the reheating of the glass and its immersion in the coloring mixture, as in the ordinary process of making red glass.

 

CUTTING, DRILLING, GRINDING. AND SHAPING GLASS:

 

To Cut Glass.

 

I.    Glass may be cut without a diamond. Dip a piece of

 


[372]

 

GLASS

 

common string in alcohol and squeeze it reasonably dry. Then tie the string tightly around the glass on the line of cutting. Touch a match to the string and let it burn off. The heat of the burning string will weaken the glass in this particular place. While it is hot plunge the glass under water, letting the arm go well under to the elbow, so there will be no vibration when the glass is struck. With the free hand strike the glass outside the line of cutting, giving a quick, sharp stroke with a stick of wood, a long-bladed knife, or the like, and the cut will be as clean and straight as if made by a regular glass cutter.

 

The same principle may be employed to cut bottles into vases, and to form all sorts of pretty things, such as jewelry boxes, picture panes, trays, small tablets, windows for a doll house, etc.

 

II.   Scratch the glass around the shape you desire with the corner of a file or graver; then, having bent a piece of wire into the same shape, heat it red hot and lay it upon the scratch and sink the glass into cold water just deep enough for the water to come almost on a level with its upper surface. It will rarely fail to break perfectly true.

 

To Cut Glass Under Water. It is possible to cut a sheet of glass roughly to any desired shape with an ordinary pair of scissors, if the operation be performed under water. Of course, a smooth edge cannot be obtained by such means, but it will be found satisfactory.

 

Drilling, Shaping, and Filing Glass. Take any good piece of steel wire, file to the shape of a drill, and then hold it in a flame till it is at a dull red heat; then quench in metallic mercury. A piece of good steel, thus treated, will bore through glass almost as easily as through soft brass. In use, lubricate with oil of turpentine in which camphor has been dissolved. When the point of the drill has touched the other side put the glass in water, and proceed with the drilling very slowly. If not possible to do this, reverse the work turn the glass over and drill, very carefully, from the opposite side. By proceeding with care you can easily drill three holes through glass 3/16 inch thick 1/4 of an inch apart.  In making the drill be careful not to make the point and the cutting edges too acute. The drill cuts more slowly, but more safely, when the point and cutting edges are at a low angle.

 

To Make Holes in Thin Glass. To produce holes in panes of thin or weak glass, provide the places to be perforated with a ring of moist loam, whose center leaves free a portion of glass exactly the size of the desired hole. Pour molten lead into the ring, and the glass and lead will fall through at once. This process is based upon the rapid heating of the glass.

 

To Grind Glass. For the grinding of glass, iron, or steel laps and fine sand are first used; after that, the sand is replaced by emery. Then the polishing is started with pure lead or pure tin laps, and finished with willow wood laps. The polishing powder is tin putty, but peroxide of iron or dioxide of tin is a good polishing medium.

 

Pohl asserts that if glass is polished with crocus (Paris red) it appears of a dark or a yellowish-brown tint. He contends that the crocus enters the pores of the glass, and, to prevent this, he uses zinc white with the most satisfactory results.

 

A Home-Made Outfit for Grinding Glass. Provide two pieces of cork, one concave and one convex (which may be cut to shape after fitting to the lathe). Take a copper cent or other suitable article and soft-solder a screw to fit the lathe, and then wax it to the cork; get a cheap emery wheel, such as is used on sewing machines. Polish the edge on the zinc collar of the emery wheel (or use a piece of zinc). The other cork should be waxed to a penny and centered. Spectacle lenses may be cut on the same emery wheel if the wheel is attached to the lathe so as to revolve. Another method is to take a common piece of window glass (green glass is the best) and make a grindstone of that, using the flat surface for grinding. Cement it on a large chuck, the glass being from 2 to 2 1/2 inches in diameter.

 

To Drill Optical Glass. A graver sharpened to a long point is twisted between the fingers, and pressed against the glass, the point being moistened from time to time with turpentine. When the hole is finished half way, the drilling should be commenced from the other side. The starting should be begun with care, as otherwise the graver is likely to slide out and scratch the lens. It is advisable to mark the point of drilling with a diamond, and not to apply too great a pressure when twisting the graver.

 

Lubricants for Glass Drilling.

 

I.    Put garlic, chopped in small pieces, into spirit of turpentine and agitate the mix-

 


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ture from time to time. Filter at the end of a fortnight, and when you desire to pierce the glass dip your bit or drill into this liquid, taking care to moisten it constantly to prevent the drill, etc., from becoming heated.

 

II.   Place a little alum in acetic acid, dip your drill into this and put a drop of it on the spot where the glass is to be pierced.

 

GILDING GLASS.

 

When it is desired to gild glass for decorative purposes use a solution of gelatin in hot water, to which an equal quantity of alcohol has been added. The glass to be gilded is covered with this solution and the gold leaf put on while wet. A sheet of soft cotton must be pressed and smoothed over the leaf until the gelatin below is evenly distributed. This prevents spots in gilding. Careful apportionment of the gelatin is necessary. If too much be used, the gold may become spotted; if too little, the binding may be too weak to allow the gold to be polished. The glass should be cleaned thoroughly before gilding. After the gold leaf is put on the whole is allowed to dry for 10 or 20 minutes, when the luster of the gold can be raised by a cautious rubbing with cotton. Then another layer of gelatin is spread on with one stroke of a soft brush, and, if especially good work be required, a second layer of gold is put on and covered as before. In this case, however, the gelatin is used hot. After the gilding has become perfectly dry the letters or ornamentation are drawn and the surplus gold around the edges is taken off. The gilding docs not become thoroughly fixed until after several months, and until then rough handling, washing, etc., should be avoided.

 

The best backing for glass gilding is asphaltum, with a little lampblack, this to be mixed up with elastic varnish; outside finishing varnish is the best, as the addition of this material gives durability.

 

GLASS MANUFACTURING:

See also Ceramics.

 

The blue tint of the common poison bottle is got by the addition of black oxide of cobalt to the molten glass; the green tint of the actinic glass bottle is obtained in the same way by the addition of potassium bichromate, which is reduced to the basylous condition, and

the amber tint is produced by the addition of impure manganese dioxide, a superior tint being produced by suphur in one form or another. The formulas for various kinds of bottle glass, which indicate the general composition of almost all glasses, are:

 

White Glass for Ordinary Molded Bottles.

 

                                    Parts by weight

Sand                                64

Lime                                6

Carbonate of sodium                 23 

Nitrate of sodium                   5 

 

White Flint Glass Containing Lead.

 

                                    Parts by weight

Sand                                63

Lime                                5

Carbonate of sodium                 21

Nitrate of sodium                   3

Red lead                            8

 

Ordinary Green Glass for Dispensing Bottles.

 

                                    Parts by weight

Sand                                63

Carbonate of sodium                 26 

Lime                                11

 

A mixture for producing a good green flint glass is much the same as that for the ordinary white flint glass, except that the lime, instead of being the purest, is ordinary slaked lime, and the sodium nitrate is omitted. Sand, lime, and sodium carbonate are the ordinary bases of glass, while the sodium nitrate is the decolorizing agent.

 

Glass Refractory to Heat. Fine sand, 70 parts; potash, 30 parts; kaolin, 25 parts.

 

Transparent Ground Glass. Take hold of the glass by one corner with an ordinary pair of fire tongs. Hold it in front of a clear fire, and heat to about 98║ F., or just hot enough to be held comfortably in the hand. Then hold the glass horizontally, ground side uppermost, and pour in the center a little photographer's dry-plate negative varnish. Tilt the glass so that the varnish spreads over it evenly, then drain back the surplus varnish into the bottle from one corner of the glass. Hold the glass in front of the fire again for a few minutes and the varnish will crystallize on its surface, making it transparent. The glass should not be made too hot before the varnish is put on, or the varnish will not run evenly. This method answers very well for self-made magic-lantern slides. Ground glass may be made temporarily transparent by wiping with a sponge dipped in paraffine or glycerine.

 

WATER-TIGHT GLASS:

 

Water-Tight Glass Roofs. Glass roofs, the skeletons of which are constructed

 


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of iron, are extremely difficult to keep water-tight, as the iron expands and contracts with atmospheric changes. To meet this evil, it is necessary to use an elastic putty, which follows the variations of the iron. A good formula is: Two parts rosin and one part tallow, melted together and stirred together thoroughly with a little minium. This putty is applied hot upon strips of linen or cotton cloth, on top and below, and these are pasted while the putty is still warm, with one edge on the iron ribs and the other, about one-fourth inch broad, over the glass.

 

Tightening Agent for Acid Receptacles. Cracked vessels of glass or porcelain, for use in keeping acids, can be made tight by applying a cement prepared in the following manner: Take finely sifted sand, some asbestos with short fiber, a little magnesia and add enough concentrated water glass to obtain a readily kneadable mass. The acid renders the putty firm and waterproof.

 

PENCILS FOR MARKING GLASS:

See also Etching and Frosted Glass.

 

Crayons for Writing on Glass.

 

I.    The following is a good formula:

 

Spermaceti                          4 parts

Tallow                              3 parts

Wax                                 2 parts

Red lead                            6 parts

Potassium carbonate                 1 part

 

Melt the spermaceti, tallow, and wax together over a slow fire, and when melted stir in, a little at a time, the potassium carbonate and red lead, previously well mixed. Continue the heat for 20 or 30 minutes, stirring constantly. Withdraw from the source of heat, and let cool down somewhat, under constant stirring, at the temperature of about 180║ F.; before the mixture commences to set, pour off into molds and let cool. The latter may be made of bits of glass tubing of convenient diameter and length. After the mixture cools, drive the crayons out by means of a rod that closely fits the diameter of the tubes.

 

II.   Take sulphate of copper, 1 part, and whiting, 1 part. Reduce these to a fine powder and mix with water; next roll this paste into the shape of crayons and let dry. When it is desired to write on the glass use one of these crayons and wipe the traced designs. To make them reappear breathe on the glass.

 

III.  Melt together, spermaceti, 3 parts; talc, 3 parts, and wax, 2 parts. When melted stir in 6 parts of minium and 1 part of caustic potash. Continue heating for 30 minutes, then cast in suitable molds. When formed and ready to be put away dust them with talc powder, or roll each pencil in paraffine powder.

 

PREVENTION OF FOGGING, DIMMING, AND CLOUDING.

 

I.    Place a few flat glass or porcelain dishes with calcium chloride in each window. This substance eagerly absorbs all moisture from the air. The contents of the dishes have to be renewed every 2 or 3 days, and the moist calcium chloride rigorously dried, whereupon it may be used over again.

 

II.   Apply to the inside face of the glass a thin layer of glycerine, which does not permit the vapor to deposit in fine drops and thus obstruct the light. Double glass may also be used. In this way the heat of the inside is not in direct contact with the cold outside.

 

III.  By means of the finger slightly moistened, apply a film of soap of any brand or kind to the mirror; then, rub this off with a clean, dry cloth; the mirror will be as bright and clear as ever; breathing on it will not affect its clearness.

 

IV.   Window glass becomes dull during storage by reason of the presence of much alkalI.      This can be avoided by taking sand, 160 parts; calcined sodium sulphate, 75; powdered marble, 50; and coke, 4 to 5 parts. About 3 parts of the sodium sulphate may be replaced by an equal quantity of potash.

 

FROSTED GLASS.

 

I.    A frosted appearance may be given to glass by covering it with a

mixture of

 

Magnesium sulphate                  6 ounces

Dextrin                             2 ounces

Water                               20 ounces

 

When this solution dries, the magnesium sulphate crystallizes in fine needles.

 

II.   Another formula directs a strong solution of sodium or magnesium sulphate, applied warm, and afterwards coated with a thin solution of acacia.

 

III.  A more permanent "frost" may be put on the glass by painting with white lead and oil, either smooth or in stipple effect. The use of lead acetate with oil gives a more pleasing effect, perhaps, than the plain white lead.

 

IV.   If still greater permanency is desired, the glass may be ground by rubbing with some gritty substance.

 


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V.    For a temporary frosting, dip a piece of flat marble into glass cutter's sharp sand, moistened with water; rub over the glass, dipping frequently in sand and water. If the frosting is required very fine, finish off with emery and water. Mix together a strong, hot solution of Epsom salt and a clear solution of gum arabic; apply warm. Or use a strong solution of sodium sulphate, warm, and when cool, wash with gum water. Or daub the glass with a lump of glazier's putty, carefully and uniformly, until the surface is equally covered. This is an excellent imitation of ground glass, and is not disturbed by rain or damp.

 

VI.   This imitates ground glass:

 

Sandarac                            2 1/2 ounces

Mastic                              1/2 ounce

Ether                               24 ounces

Benzine                             16 to 18 ounces

 

VII.  Take white lead ground in a mixture of 3/4 varnish and 1/4 oil of turpentine, to which burnt white vitriol and white sugar of lead are added for drier. The paint must be prepared exceedingly thin and applied to the glass evenly, using a broad brush. If the windows require a new coat, the old one is first removed by the use of a strong lye, or else apply a mixture of hydrochloric acid, 2 parts; vitriol, 2 parts; copper sulphate, 1 part; and gum arabic 1 part, by means of a brush. The production of this imitation frosting entails little expense and is of special advantage when a temporary use of the glass is desired.

 

VIII. A little Epsom salt (sulphate of magnesia) stirred in beer with a small dose of dextrin and applied on the panes by means of a sponge or a brush permits of obtaining mat panes.

 

Hoarfrost Glass. The feathery foams traced by frost on the inside of the windows in cold weather may be imitated as follows:

 

The surface is first ground either by sand-blast or the ordinary method, and is then covered with a sort of varnish. On being dried either in the sun or by artificial heat, the varnish contracts strongly, taking with it the particles of glass to which it adheres; and as the contraction takes places along definite lines, the pattern given by the removal of the particles of glass resembles very closely the branching crystals of frostwork. A single coat gives a small, delicate effect, while a thick film, formed by putting on 2, 3 or more coats, contracts so strongly as to produce a large and bold design.

 

By using colored glass, a pattern in half-tint may be made on the colored ground, and after decorating white glass, the back may be silvered or gilded.

 

Engraving, Matting, and Frosting. Cover the glass with a layer of wax or of varnish on which the designs are traced with a graver or pen point; next, hydrofluoric acid is poured on the tracings. This acid is very dangerous to handle, while the following process, though furnishing the same results, does not present this drawback: Take powdered fluoride of lime, 1 part, and sulphuric acid, 2 parts. Make a homogeneous paste, which is spread on the parts reserved for the engraving or frosting. At the end of 3 or 4 hours wash with water to remove the acid, next with alcohol to take off the varnish, or with essence of turpentine if wax has been employed for stopping off.

 

To Render Window Panes Opaque.

 

I.    Panes may be rendered mat and non-transparent by painting them on one side with a liquid prepared by grinding whiting with potash waterglass solution. After one or two applications, the panes are perfectly opaque, while admitting the light.

 

II.   Paint the panes with a solution of

 

                                    Parts by weight

Dextrin                             20

Zinc vitriol                        800

Bitter salt                         800 

In water                            2,000

 

III.  For deadening panes already set in frames the following is suitable: Dissolve 1 part of wax in 10 parts of oil of turpentine, adding 1 part of varnish and 1 part of siccative. With this mixture coat the panes on the outside and dab, while still wet, with a pad of cotton wadding. If desired small quantities of Paris blue, madder lake, etc., may be added to the wax solution.

 

IV.   For deadening window panes in factories and workshops: To beeswax dissolved in oil of turpentine, add some dryer and varnish to obtain a quicker drying and hardening. After the window pane has been coated with this mixture on the outside, it is dabbed uniformly with a pad of wadding. The wax may be tinted with glazing colors.

 

Frosted Mirrors.

 

I.    Cover with a solution of Epsom salts in stale beer; apply with a sponge to the mirror, first wiping it clean and dry. On drying, the

Epsom salt crystallizes, giving very handsome frosted effects, but the solution must not be applied on humid days

 


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