moss strongly boiled down in water to which a slight quantity of
previously dissolved gelatin is added. In applying the mass, which
should always be kept in a hot condition, the paper should be covered
uniformly throughout. After it has been dried well it is smoothed on
the coated side and used for a proof. The transparent colors to be used
must be ground in stronger varnish than the opaque ones. In order to
produce a handsome red, yellow lake and red sienna are used; the tone
of the latter is considerably warmer than that of the yellow lake.
Where the cost is no consideration, aurosolin may also be employed.
For pale red, madder lakes should be employed, but for darker shades,
crimson lakes and scarlet cochineal lakes. The vivid geranium lake
gives a magnificent shade, which, however, is not at all fast in
sunlight. The most translucent blue will always be Berlin blue. For
purple, madder purple is the most reliable color, but possesses little
gloss. Luminous effects can be obtained with the assistance of aniline
colors, but these are only of little permanence in transparencies.
Light, transparent green is hardly available. Recourse has to be taken
to mixing Berlin blue with yellow lake, or red sienna. Green chromic
oxide may be used if its sober, cool tone has no disturbing influence.
Almost all brown coloring bodies give transparent colors, but the most
useful are madder lakes and burnt umber. Gray is produced by mixing
purple tone colors with suitable brown, but a gray color hardly ever
{710} occurs in transparent prints. Liquid siccative must always be
added to the colors, otherwise the drying will occupy too much time.
After the drying, the prints are varnished on both sides. For this
purpose, a well-covering, quickly drying, colorless, not too thick
varnish must be used, which is elastic enough not to crack nor to break
in bending.
Frequently the varnishing of the placards is done with gelatin. This
imparts to the picture an especially handsome, luminous luster. After
an equal quantity of alcohol has been added to a readily flowing
solution of gelatin, kept for use in a zinc vessel, the gelatin
solution is poured on the glass plates destined for the transparencies.
After a quarter of an hour, take the placard, moisten its back
uniformly, and lay it upon a gelatin film which has meanwhile formed on
the glass plate, where it remains 2 to 3 days. When it is to be removed
from the plate, the edge of the gelatin film protruding over the edge
of the placard is lifted up with a dull knife, and it is thus drawn
off. A fine, transparent gloss remains on the placard proper. In order
to render the covering waterproof and pliable, it is given a coating
of collodion, which does not detract from the transparence. The glass
plates and their frames must be cleaned of adhering gelatin particles
before renewed use.
«TRANSFER PROCESSES:»
«To Transfer Designs.»—Designs can be transferred on painted surfaces,
cloth, leather, velvet, oil cloth, and linen sharply and in all the
details with little trouble. Take the original design, lay it on a
layer of paper, and trace the lines of design accurately with a packing
needle, the eye of which is held by a piece of wood for a handle. It is
necessary to press down well. The design becomes visible on the back
by an elevation. When everything has been accurately pressed through,
take, e. g., for dark objects, whiting (formed in pieces), lay the
design face downward on the knee and pass mildly with the whiting over
the elevations; on every elevation a chalk line will appear. Then dust
off the superfluous whiting with the fingers, lay the whiting side on
the cloth to hold it so that it cannot slide, and pass over it with
a soft brush. For light articles take powdered lead pencil, which is
rubbed on with the finger, or limewood charcoal. For tracing use oil
paint on cloth and India ink on linen.
«To Copy Engravings.»—To make a facsimile of an engraving expose it
in a warm, closed box to the vapor of iodine, then place it, inkside
downward, on a smooth, dry sheet of clean white paper, which has
been brushed with starch water. After the two prepared surfaces have
been in contact for a short time a facsimile of the engraving will
be reproduced more or less accurately, according to the skill of the
operator.
«To Transfer Engravings.»—The best way to transfer engraving from one
piece to another is to rub transfer wax into the engraved letters. This
wax is made of beeswax, 3 parts; tallow, 3 parts; Canada balsam, 1
part; olive oil, 1 part. If the wax becomes too hard, add a few drops
of olive oil, and if too soft, a little more beeswax. Care should be
taken that the wax does not remain on the surface about the engraving,
otherwise the impression would be blurred. Then moisten a piece of
paper by drawing it over the tongue and lay it on the engraving. Upon
this is laid another piece of dry paper, and securing both with the
thumb and forefinger of the left hand, so they will not be moved, go
over the entire surface with a burnisher made of steel or bone, with
a pointed end. This will press the lower paper into the engraving and
cause the wax to adhere to it. Then the top paper is removed and the
corner of the lower one gently raised. The whole is then carefully
peeled off, and underneath will be found a reversed, sharp impression
of the engraving. The edges of the paper are then cut so it can be
fitted in a position on the other articles similar to that on the
original one. When this is done lay the paper in the proper position
and rub the index finger lightly over it, which will transfer a clear
likeness of the original engraving. If due care is taken two dozen or
more transfers can be made from a single impression.
TRICKS WITH FIRE: See Pyrotechnics.
TUBERS, THEIR PRESERVATION: See Roots.
TUBS: TO RENDER SHRUNKEN TUBS WATER-TIGHT: See Casks.
TUNGSTEN STEEL: See Steel.
TURMERIC IN FOOD: See Foods.
TURPENTINE STAINS: See Wood. {711}
TURTLE (MOCK) EXTRACT: See Condiments.
«TWINE:»
See also Thread and Cordage.
Tough twine may be greatly strengthened by dissolving plenty of alum in
water and laying the twine in this solution. After drying, the twine
will have much increased tensile strength.
«Typewriter Ribbons»
(See also Inks.)
The constituents of an ink for typewriter ribbons may be broadly
divided into four elements: 1, the pigment; 2, the vehicle; 3, the
corrigent; 4, the solvent. The elements will differ with the kind of
ink desired, whether permanent or copying.
«Permanent (Record) Ink.»—Any finely divided, non-fading color may be
used as the pigment; vaseline is the best vehicle and wax the best
corrigent. In order to make the ribbon last a long time with one
inking, as much pigment as feasible should be used. To make black
record ink: Take some vaseline, melt it on a slow fire or water bath,
and incorporate by constant stirring as much lampblack as it will take
up without becoming granular. Take from the fire and allow it to cool.
The ink is now practically finished, except, if not entirely suitable
on trial, it may be improved by adding the corrigent wax in small
quantity. The ribbon should be charged with a very thin, evenly divided
amount of ink. Hence the necessity of a solvent—in this instance a
mixture of equal parts of petroleum benzine and rectified spirit of
turpentine. In this mixture dissolve a sufficient amount of the solid
ink by vigorous agitation to make a thin paint. Try the ink on one
extremity of the ribbon; if too soft, add a little wax to make it
harder; if too pale, add more coloring matter; if too hard, add more
vaseline. If carefully applied to the ribbon, and the excess brushed
off, the result will be satisfactory.
On the same principle, other colors may be made into ink; but for
delicate colors, albolene and bleached wax should be the vehicle and
corrigent, respectively.
The various printing inks may be used if properly corrected. They
require the addition of vaseline to make them non-drying on the ribbon,
and of some wax if found too soft. Where printing inks are available,
they will be found to give excellent results if thus modified, as the
pigment is well milled and finely divided. Even black cosmetic may be
made to answer, by the addition of some lampblack to the solution in
the mixture of benzine and turpentine.
After thus having explained the principles underlying the manufacture
of permanent inks, we can pass more rapidly over the subject of copying
inks, which is governed by the same general rules.
For copying inks, aniline colors form the pigment; a mixture of about 3
parts of water and 1 part of glycerine, the vehicle; transparent soap
(about 1/4 part), the corrigent; stronger alcohol (about 6 parts),
the solvent. The desired aniline color will easily dissolve in the hot
vehicle, soap will give the ink the necessary body and counteract the
hygroscopic tendency of the glycerine, and in the stronger alcohol
the ink will readily dissolve, so that it can be applied in a finely
divided state to the ribbon, where the evaporation of the alcohol will
leave it in a thin film. There is little more to add. After the ink
is made and tried—if too soft, add a little more soap; if too hard, a
little more glycerine; if too pale, a little more pigment. Printer’s
copying ink can be utilized here likewise.
Users of the typewriter should so set a fresh ribbon as to start at the
edge nearest the operator, allowing it to run back and forth with the
same adjustment until exhausted along that strip; then shift the ribbon
forward the width of one letter, running until exhausted, and so on.
Finally, when the whole ribbon is exhausted, the color will have been
equably used up, and on reinking, the work will appear even in color,
while it will look patchy if some of the old ink has been left here and
there and fresh ink applied over it.
UDDER INFLAMMATION: See Veterinary Formulas.
«VALVES.»
The manufacturers of valves test each valve under hydraulic pressure
before it is sent out from the factory, yet they frequently leak when
erected in the pipe lines. This is due to the misuse of the erector in
most cases. The following are the most noteworthy bad practices to be
avoided when fitting in valves:
I.—Screwing a valve on a pipe very tightly, without first closing the
valve. Closing the valve makes the body much {712} more rigid and
able to withstand greater strains and also keeps the iron chips from
lodging under the seats, or in the working parts of the valves. This,
of course, does not apply to check valves.
II.—Screwing a long mill thread into a valve. The threads on commercial
pipes are very long and should never be screwed into a valve. An elbow
or tee will stand the length of thread very well, but a suitable length
thread should be cut in every case on the pipe, when used to screw into
a valve. If not, the end of pipe will shoulder against the seat of
valve and so distort it that the valve will leak very badly.
III.—The application of a pipe wrench on the opposite end of the valve
from the end which is being screwed on the pipe. This should never be
done, as it invariably springs or forces the valve seats from their
true original bearing with the disks.
IV.—Never place the body of a valve in the vise to remove the bonnet
or centerpiece from a valve, as it will squeeze together the soft
brass body and throw all parts out of alignment. Properly to remove
the bonnet or centerpiece from a valve, either screw into each end of
the valve a short piece of pipe and place one piece of the pipe in
the vise, using a wrench on the square of bonnet; or if the vise is
properly constructed, place the square of the bonnet in same and use
the short piece of pipe screwed in each end as a lever. When using a
wrench on square of bonnet or centerpiece, use a Stillson or Trimo
wrench with a piece of tin between the teeth of the jaws and the
finished brass. It may mark the brass slightly, but this is preferable
to rounding off all the corners with an old monkey wrench which is
worn out and sprung. As the threads on all bonnets or centerpieces
are doped with litharge or cement, a sharp jerk or jar on the wrench
will start the bonnet much more quickly than a steady pull. Under no
circumstances try to replace or remove the bonnet or centerpiece of
a valve without first opening it wide. This will prevent the bending
of the stem, forcing the disk down through the seat or stripping the
threads on bonnet where it screws into body. If it is impossible to
remove bonnet or centerpiece by ordinary methods, heat the body of the
valve just outside the thread. Then tap lightly all around the thread
with a soft hammer. This method never fails, as the heat expands the
body ring and breaks the joint made by the litharge or cement.
V.—The application of a large monkey wrench to the stuffing box of
valve. Many valves are returned with the stuffing boxes split, or the
threads in same stripped. This is due to the fact that the fitter or
engineer has used a large-sized monkey wrench on this small part.
VI.—The screwing into a valve of a long length of unsupported pipe. For
example, if the fitter is doing some repair work and starts out with
a run of 2-inch horizontal pipe from a 2-inch valve connected to main
steam header, the pipe being about 18 feet long, after he has screwed
the pipe tightly into the valve, he leaves the helper to support the
pipe at the other end, while he gets the hanger ready. The helper in
the meantime has become tired and drops his shoulder on which the pipe
rests about 3 inches and in consequence the full weight of this 18-foot
length of pipe bears on the valve. The valve is badly sprung and when
the engineer raises steam the next morning the valve leaks. When a
valve is placed in the center of a long run of pipe, the pipe on each
side, and close to the valve, should be well supported.
VII.—The use of pipe cement in valves. When it is necessary to use pipe
cement in joints, this mixture should always be placed on the pipe
thread which screws into the valve, and never in the valve itself. If
the cement is placed in the valve, as the pipe is screwed into the
valve it forces the cement between the seats and disks, where it will
soon harden and thus prevent the valve from seating properly.
VIII.—Thread chips and scale in pipe. Before a pipe is screwed into
a valve it should be stood in a vertical position and struck sharply
with a hammer. This will release the chips from the thread cutting, and
loosen the scale inside of pipe. When a pipe line containing valves
is connected up, the valves should all be opened wide and the pipe
well blown out before they are again closed. This will remove foreign
substances which are liable to cut and scratch the seats and disks.
IX.—Expansion and contraction. Ample allowance must be provided for
expansion and contraction in all steam lines, especially when brass
valves are included. The pipe and fittings are much more rigid and
stiff than the brass valves and in consequence the expansion strains
will relieve themselves at the weakest point, unless otherwise provided
for. {713}
X.—The use of wrenches or bars on valve wheels to close the valves
tightly. This should never be done, as it springs the entire valve and
throws all parts out of alignment, thus making the valve leak. The
manufacturer furnishes a wheel sufficiently large properly to close
against any pressure for which it is suitable. If the valves cannot be
closed tightly by this means, there is something between the disks and
seats or they have been cut or scratched by foreign substances.
«Vanilla»
(See also Essences and Extracts.)
The best Mexican vanilla yields only in the neighborhood of 1.7 per
cent of vanillin; that from Reunion and Guadeloupe about 2.5 per
cent; and that from Java 2.75 per cent. There seems to be but little
connection between the quantity of vanillin contained in vanilla pods
and their quality as a flavor producer. Mexican beans are esteemed the
best and yet they contain far less than the Java. Those from Brazil
and Peru contain much less than those from Mexico, and yet they are
considered inferior in quality to most others. The vanillin of the
market is chiefly, if not entirely, artificial and is made from the
coniferin of such pines and firs as abies excelsa, a. pectinata, pinus
cembra, and p. strobus, as well as from the eugenol of cloves and
allspice. Vanillin also exists in asparagus, lupine seeds, the seeds of
the common wild rose, asafetida, and gum benzoin.
A good formula for a vanilla extract is the following:
Vanilla 1 ounce
Tonka 2 ounces
Alcohol, deodorized 32 fluidounces
Syrup 8 fluidounces
Cut and bruise the vanilla, afterwards adding and bruising the Tonka;
macerate for 14 days in 16 fluidounces of the alcohol, with occasional
agitation; pour off the clear liquid and set aside; pour the remaining
alcohol on the magma, and heat by means of a water bath to about
168° F., in a closely covered vessel. Keep it at that temperature for
2 or 3 hours, then strain through flannel with slight pressure; mix
the two portions of liquid and filter through felt. Lastly, add the
syrup. To render this tincture perfectly clear it may be treated with
pulverized magnesium carbonate, using from 1/2 to 1 drachm to each
pint.
«To Detect Artificial Vanillin in Vanilla Extracts» (see also
Foods).-There is no well-defined test for vanillin, but one can get
at it in a negative way. The artificial vanillin contains vanillin
identical with the vanillin contained in the vanilla bean; but
the vanilla bean, as the vanilla extract, contains among its many
“extractive matters” which enter into the food and fragrant value of
vanilla extract, certain rosins which can be identified with certainty
in analysis by a number of determining reactions. Extract made without
true vanilla can be detected by negative results in all these reactions.
Vanilla beans contain 4 to 11 per cent of this rosin. It is of a dark
red to brown color and furnishes about one-half the color of the
extract of vanilla. This rosin is soluble in 50 per cent alcohol, so
that in extracts of high grade, where sufficient alcohol is used, all
rosin is kept in solution. In cheap extracts, where as little as 20
per cent of alcohol by volume is sometimes used, an alkali—usually
potassium bicarbonate—is added to aid in getting rosin, gums, etc., in
solution, and to prevent subsequent turpidity. This treatment deepens
the color very materially.
Place some of the extract to be examined in a glass evaporating dish
and evaporate the alcohol on the water bath. When alcohol is removed,
make up about the original volume with hot water. If alkali has not
been used in the manufacture of the extract, the rosin will appear as
a flocculent red to brown residue. Acidify with acetic acid to free
rosin from bases, separating the whole of the rosin and leaving a
partly decolorized, clear supernatant liquid after standing a short
time. Collect the rosin on a filter, wash with water, and reserve the
filtrate for further tests.
Place a portion of the filter with the attached rosin in a few cubic
centimeters of dilute caustic potash. The rosin is dissolved to a
deep-red solution. Acidify. The rosin is thereby precipitated. Dissolve
a portion of the rosin in alcohol; to one fraction add a few drops
of ferric chloride; no striking coloration is produced. To another
portion add hydrochloric acid; again there is little change in color.
In alcoholic solution most rosins give color reactions with ferric
chloride or hydrochloric acid. To a portion of the filtrate obtained
above add a few drops of basic lead acetate. The precipitate is so
bulky as to almost {714} solidify, due to the excessive amount of
organic acids, gums, and other extractive matter. The filtrate from
this precipitate is nearly, but not quite, colorless. Test another
portion of the filtrate from the rosin for tannin with a solution of
gelatin. Tannin is present in varying but small quantities. It should
not be present in great excess.
«To Detect Tonka in Vanilla Extract.»—The following test depends on
the chemical difference between coumarin and vanillin, the odorous
principles of the two beans. Coumarin is the anhydride of coumaric
acid, and on fusion with a caustic alkali yields acetic and salicylic
acids, while vanillin is methyl protocatechin aldehyde, and when
treated similarly yields protocatechuic acid. The test is performed by
evaporating a small quantity of the extract to dryness, and melting
the residue with caustic potash. Transfer the fused mass to a test
tube, neutralize with hydrochloric acid, and add a few drops of ferric
chloride solution. If Tonka be present in the extract, the beautiful
violet coloration characteristic of salicylic acid will at once become
evident.
«Vanilla Substitute.»—A substitute for vanilla extract is made from
synthetic vanillin. The vanillin is simply dissolved in diluted alcohol
and the solution colored with a little caramel and sweetened perhaps
with syrup. The following is a typical formula:
Vanillin 1 ounce
Alcohol 6 quarts
Water 5 quarts
Syrup 1 quart
Caramel sufficient to color.
An extract so made does not wholly represent the flavor of the bean;
while vanillin is the chief flavoring constituent of the bean, there
are present other substances which contribute to the flavor; and
connoisseurs prefer this combination, the remaining members of which
have not yet been made artificially.
VANILLIN: See Vanilla.
«Varnishes»
(See also Enamels, Glazes, Oils, Paints, Rust Preventives, Stains, and
Waterproofing.)
Varnish is a solution of resinous matter forming a clear, limpid fluid
capable of hardening without losing its transparency. It is used to
give a shining, transparent, hard, and preservative covering to the
finished surface of woodwork, capable of resisting in a greater or
less degree the influence of the air and moisture. This coating, when
applied to metal or mineral surfaces, takes the name of lacquer, and
must be prepared from rosins at once more adhesive and tenacious than
those entering into varnish.
The rosins, commonly called gums, suitable for varnish are of two
kinds—the hard and the soft. The hard varieties are copal, amber, and
the lac rosins. The dry soft rosins are juniper gum (commonly called
sandarac), mastic, and dammar. The elastic soft rosins are benzoin,
elemi, anime, and turpentine. The science of preparing varnish consists
in combining these classes of rosins in a suitable solvent, so that
each conveys its good qualities and counteracts the bad ones of the
others, and in giving the desired color to this solution without
affecting the suspension of the rosins, or detracting from the drying
and hardening properties of the varnish.
In spirit varnish (that made with alcohol) the hard and the elastic
gums must be mixed to insure tenderness and solidity, as the alcohol
evaporates at once after applying, leaving the varnish wholly dependent
on the gums for the tenacious and adhesive properties; and if the
soft rosins predominate, the varnish will remain, “tacky” for a long
time. Spirit varnish, however good and convenient to work with, must
always be inferior to oil varnish, as the latter is at the same time
more tender and more solid, for the oil in oxidizing and evaporating
thickens and forms rosin which continues its softening and binding
presence, whereas in a spirit varnish the alcohol is promptly
dissipated, and leaves the gums on the surface of the work in a more or
less granular and brittle precipitate which chips readily and peels off.
Varnish must be tender and in a manner soft. It must yield to the
movements of the wood in expanding or contracting with the heat or
cold, and must not inclose the wood like a sheet of glass. This is why
oil varnish is superior to spirit varnish. To obtain this suppleness
the gums must be dissolved in some liquid not highly volatile like
spirit, but one which mixes with them in substance permanently to
counteract their extreme friability. Such solvents are the oils of
lavender, spike, rosemary, and turpentine, combined with linseed oil.
The vehicle in which the rosins are dissolved must be soft and remain
so in order to {715} keep the rosins soft which are of themselves
naturally hard. Any varnish from which the solvent has completely dried
out must of necessity become hard and glassy and chip off. But, on the
other hand, if the varnish remains too soft and “tacky,” it will “cake”
in time and destroy the effect desired.
Aside from this, close observers if not chemists will agree that for
this work it is much more desirable to dissolve these rosins in a
liquid closely related to them in chemical composition, rather than in
a liquid of no chemical relation and which no doubt changes certain
properties of the rosins, and cuts them into solution more sharply
than does turpentine or linseed oil. It is a well-known fact that each
time glue is liquefied it loses some of its adhesive properties. On
this same principle it is not desirable to dissolve varnish rosins
in a liquid very unlike them, nor in one in which they are quickly
and highly soluble. Modern effort has been bent on inventing a cheap
varnish, easily prepared, that will take the place of oil varnish, and
the market is flooded with benzine, carbon bisulphide, and various
ether products which are next to worthless where wearing and durable
properties are desired.