Magdala red, opaque scarlet (1), brilliant carmine (2).
Quinine, pale blue (1), no color (2).
Safranine, yellow red (1), crimson (2).
FLUXES USED IN ENAMELING: See Enameling.
FLUXES FOR SOLDERING: See Soldering.
«Fly-Papers and Fly-Poisons»
(See also Insecticides.)
«Sticky Fly-Papers.»—The sticky material applied to the paper is the
following:
I.—Boiled linseed oil 5 to 7 parts
Gum thus 2 to 3 parts
Non-drying oil 3 to 7 parts
For the non-drying oil, cottonseed, castor, or neatsfoot will answer—in
fact, any of the cheaper oils that do not readily dry or harden will
answer. The proper amount of each ingredient depends upon the condition
of the boiled oil. If it is boiled down very stiff, more of the other
ingredients will be necessary, while if thin, less will be required.
II.—Rosin 8 parts
Rapeseed oil 4 parts
Honey 1 part
Melt the rosin and oil together, and incorporate the honey. Two parts
of raw linseed oil and 2 parts of honey may be used along with 8 parts
of rosin instead of the foregoing. Use paper already sized, as it comes
from the mills, on which to spread the mixture.
III.—Castor oil 12 ounces
Rosin 27 ounces
Melt together and spread on paper sized with glue, using 12 ounces glue
to 4 pints water.
IV.—Rosin 8 ounces
Venice turpentine 2 ounces
Castor oil 2 ounces
Spread on paper sized with glue.
«Poisonous Fly-Papers.»—
I.—Quassia chips 150 parts
Chloride of cobalt 10 parts
Tartar emetic 2 parts
Tincture of long pepper (1 to 4) 80 parts
Water 400 parts
Boil the quassia in the water until the liquid is reduced one-half,
strain, add the other ingredients, saturate common absorbent paper with
the solution, and dry. The paper is used in the ordinary way.
II.—Potassium bichromate 10 ounces
Sugar 3 drachms
Oil of black pepper 2 drachms
Alcohol 2 ounces
Water 14 ounces
Mix and let stand for several days, then soak unsized paper with the
solution.
III.—Cobalt chloride 4 drachms
Hot water 16 ounces
Brown sugar 1 ounce
Dissolve the cobalt in the water and add the sugar, saturate unsized
paper in the solution, and hang up to dry.
IV.—Quassia chips 150 parts
Cobalt chloride 10 parts
Tartrate antimony 2 parts
Tincture of pepper 80 parts
Water 400 parts
Boil chips in the water until the volume of the latter is reduced
one-half, add other ingredients and saturate paper and dry.
«Fly-Poison.»—
Pepper 4 ounces
Quassia 4 ounces
Sugar 8 ounces
Diluted alcohol 4 ounces
Mix dry and sprinkle around where the flies can get it.
«Non-Poisonous Fly-Papers.»—I.—Mix 25 parts of quassia decoction (1:10)
with 6 parts of brown sugar and 3 parts of ground pepper, and place on
flat dishes.
II.—Mix 1 part of ground pepper and 1 part of brown sugar with 16 parts
milk {348} or cream, and put the mixture on flat plates.
III.—Macerate 20 parts of quassia wood with 100 parts of water for 24
hours, boil one-half hour, and squeeze off 24 hours. The liquid is
mixed with 3 parts of molasses, and evaporated to 10 parts. Next add
1 part of alcohol. Soak blotting paper with this mixture, and put on
plates.
IV.—Dissolve 5 parts of potassium bichromate, 15 parts of sugar, and 1
part of essential pepper oil in 60 parts of water, and add 10 parts of
alcohol. Saturate unsized paper with this solution and dry well.
V.—Boil together for half an hour
Ground quassia wood 18 pounds
Broken colocynth 3 pounds
Ground long pepper 5 pounds
Water 80 pounds
Then percolate and make up to 60 pounds if necessary with more water.
Then add 4 pounds of syrup. Unsized paper is soaked in this, and dried
as quickly as possible to prevent it from getting sour.
VI.—Mix together
Ordinary syrup 100 ounces
Honey 30 ounces
Extract of quassia wood 4 ounces
Oil of aniseed, a few drops.
«Removing the Gum of Sticky Fly-Paper.»—The “gum” of sticky fly-paper
that has “leaked” over furniture and shelfware can be removed without
causing injury to either furniture or bottles.
The “gum” of sticky fly-paper, while being quite adhesive, is easily
dissolved with alcohol (grain or wood) or oil of turpentine. Alcohol
will not injure the shelfware, but it should not be used on varnished
furniture; in the latter case turpentine should be used.
FLY PROTECTIVES FOR ANIMALS: See Insecticides.
«FOAM PREPARATIONS.»
A harmless gum cream is the following:
I.—Digest 100 parts of Panama wood for 8 days with 400 parts of water
and 100 parts of spirits of wine (90 per cent). Pour off without strong
pressure and filter.
For every 5 parts of lemonade syrup take 5 parts of this extract,
whereby a magnificent, always uniform foam is obtained on the lemonade.
II.—Heat 200 parts of quillaia bark with distilled water during an hour
in a vapor bath, with frequent stirring, and squeeze out. Thin with
water if necessary and filter.
«FOOD ADULTERANTS, SIMPLE TESTS FOR THEIR DETECTION.»
Abstract of a monograph by W. D. Bigelow and Burton J. Howard,
published by the Department of Agriculture.
Generally speaking, the methods of chemical analysis employed in food
laboratories can be manipulated only by one who has had at least
the usual college course in chemistry, and some special training in
the examination of foods is almost as necessary. Again, most of the
apparatus and chemicals necessary are entirely beyond the reach of the
home, and the time consumed by the ordinary examination of a food is in
itself prohibitive.
Yet there are some simple tests which serve to point out certain forms
of adulteration and can be employed by the careful housewife with the
reagents in her medicine closet and the apparatus in her kitchen. The
number may be greatly extended by the purchase of a very few articles
that may be procured for a few cents at any drug store. In applying
these tests, one general rule must always be kept carefully in mind.
Every one, whether layman or chemist, must familiarize himself with a
reaction before drawing any conclusions from it. For instance, before
testing a sample of supposed coffee for starch, the method should
be applied to a sample of pure coffee (which can always be procured
unground) and to a mixture of pure coffee and starch prepared by the
operator.
Many manufacturers and dealers in foods have the ordinary senses so
highly developed that by their aid alone they can form an intelligent
opinion of the nature of a product, or of the character, and sometimes
even of the proportion of adulterants present. This is especially true
of such articles as coffee, wine, salad oils, flavoring extracts,
butter, and milk. The housewife finds herself constantly submitting
her purchases to this test. Her broad experience develops her senses
of taste and smell to a high degree, and her discrimination is often
sharper and more accurate than she herself realizes. The manufacturer
who has developed his natural senses most {349} highly appreciates best
the assistance or collaboration of the chemist, who can often come to
his relief when his own powers do not avail. So the housewife, by a few
simple chemical tests, can broaden her field of vision and detect many
impurities that are not evident to the senses.
There are here given methods adapted to this purpose, which may be
applied to milk, butter, coffee, spices, olive oil, vinegar, jams and
jellies, and flavoring extracts. In addition to this some general
methods for the detection of coloring matter and preservatives will be
given. All of the tests here described may be performed with utensils
found in any well-appointed kitchen. It will be convenient, however,
to secure a small glass funnel, about 3 inches in diameter, since
filtration is directed in a number of the methods prescribed. Filter
paper can best be prepared for the funnel by cutting a circular piece
about the proper size and folding it once through the middle, and then
again at right angles to the first fold. The paper may then be opened
without unfolding in such a way that three thicknesses lie together on
one side and only one thickness on the other. In this way the paper may
be made to fit nicely into the funnel.
Some additional apparatus, such as test tubes, racks for supporting
them, and glass rods, will be found more convenient for one who desires
to do considerable work on this subject, but can be dispensed with.
The most convenient size for test tubes is a diameter of from 1/2 to
5/8 inch, and a length of from 5 to 6 inches. A graduated cylinder
will also be found very convenient. If this is graduated according to
the metric system, a cylinder containing about 100 cubic centimeters
will be found to be convenient; if the English liquid measure is used
it may be graduated to from 3 to 8 ounces.
«Chemical Reagents.»—The word “reagent” is applied to “any substance
used to effect chemical change in another substance for the purpose
of identifying its component parts or determining its percentage
composition.” The following reagents are required in the methods here
given:
Turmeric paper.
Iron alum (crystal or powdered form).
Hydrochloric acid† (muriatic acid), concentrated.
Iodine tincture.
Potassium permanganate, 1 per cent solution.
Alcohol (grain alcohol).
Chloroform.
Boric acid or borax.
Ammonia water.
Halphen’s reagent.
────────────────────────────
† Caution.—All tests in which hydrochloric acid is used should be
conducted in glass or earthenware, for this acid attacks and will
injure metal vessels. Care must also be taken not to bring it into
contact with the flesh or clothes. If, by accident, a drop of it falls
upon the clothes, ammonia, or in its absence a solution of saleratus
or sal soda (washing soda), in water, should be applied promptly.
With the exception of the last reagent mentioned, these substances may
be obtained in any pharmacy. The Halphen reagent should be prepared by
a druggist, certainly not by an inexperienced person.
It is prepared as follows: An approximately 1 per cent solution
of sulphur is made by dissolving about 1/3 of a teaspoonful of
precipitated sulphur in 3 or 4 ounces of carbon bisulphide. This
solution mixed with an equal volume of amyl alcohol forms the reagent
required by the method. A smaller quantity than that indicated by these
directions may, of course, be prepared.
If turmeric paper be not available it may be made as follows: Place a
bit of turmeric powder (obtainable at any drug store) in alcohol, allow
it to stand for a few minutes, stir, allow it to stand again until it
settles, dip a strip of filter paper into the solution, and dry it.
«Determination of Preservatives.»—The following methods cover all of
the more important commercial preservatives with the exception of
sulphites and fluorides. These are quite frequently used for preserving
foods—the former with meat products and the latter with fruit
products—but, unfortunately, the methods for their detection are not
suitable for household use.
«Detection of Salicylic Acid.»—The determination of salicylic acid
can best be made with liquids. Solid and semi-solid foods, such as
jelly, should be dissolved, when soluble, in sufficient water to make
them thinly liquid. Foods containing insoluble matter, such as jam,
marmalade, and sausage, may be macerated with water and strained
through a piece of white cotton cloth. The maceration may be performed
by rubbing in a teacup or other convenient vessel with a heavy spoon.
Salicylic acid is used for preserving {350} fruit products of all
kinds, including beverages. It is frequently sold by drug stores as
fruit acid. Preserving powders consisting entirely of salicylic acid
are often carried from house to house by agents. It may be detected as
follows:
Between 2 and 3 ounces of the liquid obtained from the fruit products,
as described above, are placed in a narrow bottle holding 5 ounces,
about a quarter of a teaspoonful of cream of tartar (or, better,
a few drops of sulphuric acid) is added, the mixture shaken for 2
or 3 minutes, and filtered into a second small bottle. Three or 4
tablespoonfuls of chloroform are added to the clear liquid in the
second bottle and the liquids mixed by a somewhat vigorous rotary
motion, poured into an ordinary glass tumbler, and allowed to stand
till the chloroform settles out in the bottom. Shaking is avoided,
as it causes an emulsion which is difficult to break up. As much as
possible of the chloroform layer (which now contains the salicylic
acid) is removed (without any admixture of the aqueous liquid) by means
of a medicine dropper and placed in a test tube or small bottle with
about an equal amount of water and a small fragment—a little larger
than a pinhead—of iron alum. The mixture is thoroughly shaken and
allowed to stand till the chloroform again settles to the bottom. The
presence of salicylic acid is then indicated by the purple color of the
upper layer of liquid.
«Detection of Benzoic Acid.»—Benzoic acid is also used for preserving
fruit products. Extract the sample with chloroform as in the case
of salicylic acid; remove the chloroform layer and place it in a
white saucer, or, better, in a plain glass sauce dish. Set a basin
of water—as warm as the hand can bear—on the outside window ledge
and place the dish containing the chloroform extract in it, closing
the window until the chloroform has completely evaporated. In this
manner the operation may be conducted with safety even by one who is
not accustomed to handling chloroform. In warm weather the vessel of
warm water may, of course, be omitted. Benzoic acid, if present in
considerable amount, will now appear in the dish in characteristic
flat crystals. On warming the dish the unmistakable irritating odor
of benzoic acid may be obtained. This method will detect benzoic
acid in tomato catsup or other articles in which it is used in large
quantities. It is not sufficiently delicate, however, for the smaller
amount used with some articles, such as wine. It is often convenient to
extract a larger quantity of the sample and divide the chloroform layer
into two portions, testing one for salicylic acid and the other for
benzoic acid.
«Detection of Boric Acid and Borax.»—Boric acid (also called boracic
acid) and its compound with sodium (borax) are often used to preserve
animal products, such as sausage, butter, and sometimes milk. For the
detection of boric acid and borax, solids should be macerated with a
small amount of water and strained through a white cotton cloth. The
liquid obtained by treating solids in this manner is clarified somewhat
by thoroughly chilling and filtering through filter paper.
In testing butter place a heaping teaspoonful of the sample in a
teacup, add a couple of teaspoonfuls of hot water, and stand the cup in
a vessel containing a little hot water until the butter is thoroughly
melted. Mix the contents of the cup well by stirring with a teaspoon
and set the cup with the spoon in it in a cold place until the butter
is solid. The spoon with the butter (which adheres to it) is now
removed from the cup and the turbid liquid remaining strained through a
white cotton cloth, or, better, through filter paper. The liquid will
not all pass through the cloth or filter paper, but a sufficient amount
for the test may be secured readily.
In testing milk for boric acid 2 or 3 tablespoonfuls of milk are placed
in a bottle with twice that amount of a solution of a teaspoonful of
alum in a pint of water, shaken vigorously, and filtered through filter
paper. Here again a clear or only slightly turbid liquid passes through
the paper.
About a teaspoonful of the liquid obtained by any one of the methods
mentioned above is placed in any dish, not metal, and 5 drops of
hydrochloric (muriatic) acid added. A strip of turmeric paper is dipped
into the liquid and then held in a warm place—near a stove or lamp—till
dry. If boric acid or borax was present in the sample the turmeric
paper becomes bright cherry red when dry. A drop of household ammonia
changes the red color to dark green or greenish black. If too much
hydrochloric acid is used the turmeric paper may take on a brownish-red
color even in the absence of boric acid. In this case, however, ammonia
changes the color to brown just as it does turmeric paper which has not
been dipped into the acid solution. {351}
«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
{352} 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.