copper-plate are to be taken, should be moistened, or wet down two or
three days previous to printing; this is performed by dipping the
sheets in water severally, and then laying them all together under a
heavy weight till they are used. When the paper is ready, the
copper-plate may be warmed over a chafing dish of coals, and the
engraved side completely covered and all the lines filled with common
printing ink, or ink made of Frankfort black, finely ground in old
linseed oil. This may be done by means of a printing ball, or the ink
may be spread on the plate with a smooth stiff brush. The plate may
then be wiped with a piece of linen or cotton cloth, and afterward
with the hand, being passed slowly but hardly over the plate to take
off all the ink except what remains in the lines of the engraving; to
accomplish which more effectually, the hand may be rubbed occasionally
with dry whiting. When the plate is thoroughly cleaned of the
redundant ink, it may be laid on the table of a rolling press, and
having a sheet of the moistened paper laid upon the face of it, and a
piece of fine broad-cloth over the paper, the whole may be passed
through the press. Then on taking up the paper, it will be found to
have received a black impression from the plate, according to the
engraving or etching, and the plate may be again carried to the fire,
to be blacked again as before. This is the usual manner of printing;
but when a rolling press is not at hand, the plate and moistened paper
may by other means, be pressed hard and firmly together, and the paper
will have received the impression equally as fair. Any of the colours,
commonly used in oil painting, being ground very thick in oil may be
substituted for ink in copper-plate printing. The plate, after being
used, should be wiped clean with a piece of flannel, moistened with
olive oil.
61. ETCHING LETTERS OR FLOWERS ON GLASS.--Select a piece of glass that
is thick and straight, and lay a coat of melted bees-wax on the
fairest side; then with a needle, pen-knife, or any other convenient
pointed instrument, trace any design, or picture, which being placed
under the glass, may be seen through the wax; or form any letters or
figures on the glass, carefully cutting or scoring quite through the
wax, and making the lines large or small as occasion may require. Then
warm a piece of the wax, so as to form it into a roll, about one
fourth of an inch in diameter; lay this roll round the work upon the
glass, and press it down so as to make it adhere to the glass, thus
forming a border. Then take some finely powdered fluate of lime, and
strew it evenly over the glass, on the waxed side, that it may fill
all the lines in the wax; and then gently pour upon it, so as not to
displace the powder, as much sulphuric acid, diluted with thrice its
weight of water, as is sufficient to cover the powdered fluate of
lime. Let every thing remain in this state for three hours; then pour
off the mixture, and clean the glass by washing it with spirits of
turpentine. The figures which were scored in the wax, will be found
engraven on the glass; while the parts which the wax covered, will be
uncorroded.--This glass plate may be charged with ink, (or any thick
oil paint) and impressions may be taken from it on paper, the same as
from copper plates, only caution is requisite, that the glass be not
broken by the pressure. _Note._--The fluoric acid, which is partly
absorbed by the water, in the above process, being very corrosive,
should not be suffered to touch the hands, nor any valuable vessel
whatever.
62. TO PRINT FIGURES WITH A SMOOTH STONE.--Take a piece of marble or
slate, and form a smooth plane surface on one side, and on this, paint
any letters or figures with common oil paint of any colour. When this
is dry, wet the stone with water, which will not adhere to the painted
figures, especially if the paints were mixed with old linseed oil,
that will produce a sharp gloss. Then apply a printer's ink-ball to
the plane surface, by which means the dry painted figures will be
covered with the ink, while the bare surface of the stone, being wet,
will not be blackened or affected by it. Press the figured surface
upon some moistened paper, and it will give a fair impression of the
painted figures, on the paper. The block of stone must be then dipped
in the water, and again inked as before, Thus many impressions may be
taken with a tolerable degree of accuracy.
63. TO CUT GLASS WITH A PIECE OF IRON.--Draw with a pencil on paper,
any pattern to which you would have the glass conform; place the
pattern under the glass, holding both together in the left hand, (for
the glass must not rest on any plane surface;) then take a common
spike or some similar piece of iron,--heat the point of it to redness,
and apply it to the edge of the glass; draw the iron slowly forward,
and the edge of the glass will immediately crack; continue moving the
iron slowly over the glass, tracing the pattern, and the chink in the
glass will follow at the distance of about half an inch, in every
direction according to the motion of the iron. It may sometimes be
found requisite, however, especially in forming corners, to apply a
wet finger to the opposite side of the glass. Tumblers and other
glasses may be cut or divided very fancifully by similar means. The
iron must be reheated as often as the crevice in the glass ceases to
follow.
64. BEST CEMENT FOR JOINING GLASS.--If the glass is not likely to be
exposed to moisture, the pieces may be joined by a solution of equal
parts of gum-arabic and loaf sugar in water; or if these are not at
hand, the white of an egg may answer nearly as well. But a strong
water proof cement that is equally transparent, may be made by
digesting finely powdered gum-copal, in thrice its weight of sulphuric
ether till it is dissolved. This solution may be applied to the edges
of the broken glass, with a camel hair pencil, and the pieces must be
put together immediately and pressed close till they adhere.
65. BEST CEMENT FOR JOINING CHINA OR CROCKERY.--Heat a piece of chalk
to a full red heat in a fire; and while this is heating, take the
white of an egg, and mix and beat together with it, one fourth of its
weight of pondered or scraped cheese, (such as is most void of cream,
or oily matter is preferable) or the curd that is formed by adding
vinegar to skimmed milk;--take the chalk from the fire, and before it
is cold, reduce it to powder, and add as much of it to the mixture as
will form a thick paste, and beat them anew all together, and use the
composition immediately. When this is dry, it will resist, in a great
measure, either heat or moisture. A semi-transparent cement, suitable
for china ware, may be made by gently boiling the flour of rice with
water.
66. TO MAKE A STRONG WATER PROOF GLUE.--Dissolve common glue in water
in the usual way, and dip into it some clean paper, sufficient to take
up an ounce or more of the glue. When the paper is nearly dry, roll it
up, or cut it into strips and put them into a wide mouthed phial or
flask, with about four ounces of alcohol; suspend this over a fire so
as to boil it gently for an hour, having the cork set in slightly to
prevent its taking fire, but not so as to prevent the vapour entirely.
Then take out the paper (the only use of which is to give the glue
more surface for the action of the alcohol) and add one ounce of
gum-shellac in powder; continue the heat, often shaking the mixture
till the shellac is dissolved. Then evaporate it to the proper
consistence for use. _Note._--Many experiments have been made, in
order to discover some aqueous size, that when dry, would resist
moisture: and some have recommended skimmed milk, and others vinegar
as a menstruum for the glue. But it does not appear from trial, that
either of these are but very little better for this purpose than
water; nor is it probable that any similar composition of size will
resist moisture much better than common glue, especially if it be
mixed with sulphate of lime, or some similar substance by way of
support.
67. THE ART OF MOULDING FIGURES IN RELIEF.--Mix together and temper
with a solution of gum-arabic in water, one part of clean, sifted
wood-ashes, and two parts of fine sulphate of lime. Knead this
composition on a board, till it has the consistence of putty. Press a
ball of this putty on any medal, coin or carved work in relief, (which
must be previously oiled) and let it dry; then take off the mould thus
formed, and oil the part that has received the impression of the
figure, with olive oil;--make a small orifice through the mould, from
the centre, or deepest part of the impression; also, pare off the
border of the mould, to within half an inch of the impressed figure.
Then lay a small piece of the putty on the board and press the mould
down hard upon it, that it may not only fill the mould, but that the
redundant part may be pressed out beyond the border of the mould:
raise the mould a little and blow through the orifice, to detach the
new moulded figure from the mould. Thus any number of figures may be
readily produced, suitable for ornamenting chimney pieces, or
mouldings, and which will be very hard when dry, and may be painted
with any coloured oil paints, which will also preserve them from
moisture.
68. TO CAST IMAGES IN PLASTER.--For this purpose a model of the figure
that is to be cast, must be provided, and suspended by a rod or staff,
one inch in diameter, and fixed in the top of the head. This model may
be made of wood, chalk, or any other substance that is smooth, and
sufficiently cohesive to support itself. This being prepared, mix fine
sulphate of lime with water, to the consistence of soft putty, and
having brushed some olive oil over the model, cover it completely with
the plaster, which must be applied, and spread over it with the hands,
to the depth of two inches or more. When the plaster is nearly dry,
divide it into several parts with a thin blade, so as to take it off
from the model without breaking any part. When the several parts of
the mould are dry, oil them inside and put them together as before,
and bind them with pieces of tape or twine; set the mould upright, and
fill it with a fresh mixture of sulphate of lime and water, of as much
consistence as may be poured in through the aperture at the head. This
plaster should be poured into the mould as quick as possible after
being mixed; otherwise it would become too stiff, and be spoiled. The
plaster in the mould will soon cohere, so that the mould may be taken
off, and the figures may be set up to dry; and the mould being oiled
and put together again, is ready for another cast.
69. TO PRODUCE EMBOSSED LETTERS, OR FIGURES ON MARBLE.--Take some of
the coloured varnish described at 37, and with a hair pencil, draw the
letters, &c. on the marble, (which should be previously well
polished,) and also cover with the varnish, every part of the face of
the marble that is to remain plain. Lay the marble in a horizontal
position and make a border of oil putty round it, and pour on muriatic
acid to the depth of half an inch on the marble. When ebulition
ceases, the acid may be drained off, and the work examined; and if the
letters are not sufficiently prominent, a fresh quantity of the acid
may be added. When the work has been thus corroded to the depth
required, the varnish may be washed off with spirits of turpentine.
The acid that has been thus employed need not be lost, for a muriate
of lime being thus formed, may be crystallized by a slight
evaporation, and preserved for other purposes; or by the addition of a
small quantity of sulphuric acid a sulphate of lime is precipitated,
and the muriatic may be poured off and be used again for the same or a
similar purpose.
70. TO SOFTEN STONE.--Marble or granite may be deprived in some
measure, of the property of cohesion by being heated red hot and then
quenched in oil. In this case, the carbonic acid which constitutes the
cohesive property of the stone, is expelled by the heat; and the
vacuum thus produced in its pores, are in some measure, filled by the
oil by the pressure of the atmosphere; by which means the stone
acquires a texture quite different from what it had previously. This
however, is not often applied to any valuable purpose.
71. TO CHANGE WOOD APPARENTLY, TO STONE.--Provide a block, or plank of
soft wood, of the dimensions required, and give it two or three coats
of linseed oil, allowing each to dry. Then having prepared some pieces
of marble or granite as directed in the last experiment, pulverize
them to a gross powder; brush over the wood with a heavy coat of copal
varnish (see 47) mixed with an equal quantity of venice turpentine;
let this rest about an hour, and then strew the stone powder over
every part of it, so as to cover the surface completely. If marble is
to be imitated, the powder of different colours, especially the white
and blue, may be prepared separately, and may be strewed on the work
in such shades as will appear the most natural. Granite may also be
crossed or striped occasionally with streaks of a coarser grain, which
will give it a very deceptive effect. When the varnish is thus covered
with stone, a heavy roller, or round log of wood, having a blanket
folded and wrapped round it, should be rolled over the work, that the
larger grains, (which of course will be the most exposed,) may the
more firmly adhere. In this manner, a very perfect imitation of stone
may be given, and the wood thus prepared will be exceedingly durable,
and will answer for many purposes, as well as real stone.
72. TO RENDER WOOD, CLOTH OR PAPER FIRE-PROOF.--Dissolve one ounce of
alum, half an ounce of sub-borate of soda and half an ounce of cherry
tree gum, in half a pint of vinegar. Dip any cloth or pieces of paper,
or wood, in this mixture and let them dry;--they cannot afterwards be
ignited so as to blaze, but may be considered safe with regard to
their taking fire by accident. _Note._--Though this composition is a
very powerful preventive against fire, it is too complex for common
use, and has too much colour for white cloths or papers; but a
solution of one ounce of sub-borate of soda in a pint of water is very
transparent and harmless, and will answer in most cases nearly as
well.
73. TO PRODUCE FIRE READILY.--_Process 1._ Mix together gently but
intimately, two or three grains of chlorate of potass, and an equal
quantity of loaf sugar, both previously reduced to fine powder:--dip
the end of a strip of glass, or a straw in sulphuric acid, and with it
gently touch the powder,--it will instantly burst into flame.
74. _Process 2._--Upon one drachm of spirits of turpentine, in a
glass, pour an equal quantity of a mixture of three parts of nitric,
with one of sulphuric acid. Instantaneous inflammation, accompanied by
the production of a large quantity of black smoke, will be the result.
75. PROCESS 3.--Take a piece of phosphorus of the size of a pin's
head, and wrap it in a piece of dry brown paper: rub the paper with a
piece of wood, or any hard body, and it will instantly inflame.
_Note._--In handling phosphorus, it is proper to have a piece of paper
or cloth intervene between the stick of phosphorus and the fingers;
and the phosphorus should be kept under water except when wanted for
use.
76. TO MAKE SUPER-COMBUSTIBLE MATCHES.--Prepare any number of small
strips or splinters of pine or other light wood, which may be about
two inches in length and one twelfth of an inch in diameter; dip one
end of each in melted sulphur to the depth of one fourth of an inch.
When they are cold, scrape off most of the sulphur, and dip the ends
of them slightly in a paste made of ten parts of chlorate of potass,
five parts of loaf sugar and one part of red lead, mixed and ground
together in alcohol. Afterwards they may be readily ignited or kindled
at any time by application of the smallest quantity of sulphuric acid.
For this purpose, the ends of them may be dipped or rather barely
touched to the acid in a phial, or, which is a better way, a strip of
glass, or even wood may be dipped in the acid and applied to the
match.
77. TO MAKE GUN POWDER.--Pulverize separately, five drachms of nitrate
of potass, one of sulphur, and one of newly burnt charcoal. Mix them
together with a little water, so as to make the compound into a dough;
form this dough into rolls of the size of a small wire, which may be
done by rolling small quantities between two boards. Lay a few of
these rolls together, and cut them into very small grains, and place
them on a sheet of paper, in a warm place, to dry. The dough may be
prevented sticking to the board while rolling it, by rubbing on the
board, a little of the dry compound powder. When the grains are
thoroughly dry, they are ready for use or experiment. On the same
principle, gun powder is manufactured on the large scale, but then the
several parts of the operation, are performed by machinery, otherwise
it would be a very expensive commodity.
78. TO MAKE THE COMMON FULMINATING POWDERS.--Grind and mix intimately,
three parts of nitrate of potass, with two of sub-carbonate of potass,
and one of sulphur. If half a drachm of this compound be placed on a
shovel, and held over a gentle fire, it will soon explode with a loud
report. It is not, however, attended with any danger. If two grains of
chlorate of potass in powder and one of sulphur be mixed together, and
wrapped in a piece of strong paper, and the paper be then struck with
a hammer, it will also explode with detonation. This experiment may
require some caution. _Note._--The percussion powder, such as is used
for priming the patent percussion rifles, is composed of chlorate of
potass, and flour of sulphur, with a trifling proportion of charcoal
and loaf sugar, being made into a paste or dough with alcohol,--then
grained and dried.
79. TO MAKE THE MERCURIAL FULMINATING POWDER.--Dissolve half an ounce
of mercury in three ounces of nitric acid, assisting the solution by a
gentle heat. When the solution is cold, pour it upon an equal quantity
of strong alcohol previously introduced into a flask, and apply a
moderate heat till effervescence is excited. (Do not forget that the
mercurial solution must be poured upon the alcohol, and not the
alcohol upon the solution.) A white fume will soon begin to undulate
on the surface of the liquor, and flow through the neck of the flask,
and a white powder will be gradually precipitated. As soon as any
precipitate ceases to fall, quickly pour the contents of the flask on
a filter; wash the powder with pure water, and cautiously dry it by a
heat not exceeding that of boiling water. The immediate washing the
powder is material, because it is liable to the re-action of the
nitric acid; and while any of that acid adheres to it, it is very
subject to be decomposed by the action of light. This powder, if very
pure and nicely made, explodes by percussion, or a moderate degree of
heat. _Experiment._--Place one-fourth of a grain of this powder,
between the ends of two slips of paste-board, and paste, or bind them
firmly together;--hold the ends of the slips over the flame of a
candle, and as soon as it becomes warm, it will explode with a loud
report. This composition is less dangerous than the fulminating
compounds of gold or silver, as it never explodes spontaneously; but
yet it cannot be handled with too much caution. _Note._--The silver
powder, or fulminating silver, with which torpedoes and waterloo
crackers are charged, is prepared in a similar manner; pure silver
being dissolved instead of mercury, but it is too dangerous to be
trifled with.
80. TO KINDLE A FIRE UNDER WATER.--Put into a deep wine-glass, that is
small at the bottom, three or four bits of phosphorus, about the size
of flax seeds, and two or three times the quantity of chlorate of
potass, in grains or crystals, and fill the glass nearly full of
water. Then place the end of a tobacco-pipe stem directly on, or over
the chlorate and phosphorus, and pour nearly a tea-spoon full of
sulphuric acid into the bowl of the pipe, that it may fall directly on
the phosphorus; a violent action will ensue, and the phosphorus will
burn vividly, with a very curious light under the water.
81. TO LIGHT A CANDLE BY APPLICATION OF ICE.--Attach to the wick of a
candle, a small piece, or globule of potassium (the metallic base of
potass) of the size of a small shot. Apply an icicle or point of ice
to the metal, and it will instantly inflame. _Note._--This curious
substance, which has the peculiar property of being ignited by coming
in contact with ice or water, has been lately discovered by Sir
Humphrey Davy. It is produced by making pure potass a part of the
circuit of a powerful Voltaic battery. It cannot be preserved but by
being kept immersed in naptha, a kind of oil of which oxygen is not a
constituent.
82. TO FORM LETTERS OR FLOWERS OF REAL FLAME.--Provide a tin chest of
about eighteen inches in length, equal in height and one inch in
breadth. Chalk any design, of letters or flowers on the face of this
chest, and pierce each line with rows of small holes, which should be
about half an inch distant from each other.--Make an aperture at the
top, through which pour about a pint of a mixture of rum and spirits
of turpentine. Place two or three lamps under the bottom of the chest
(which must be raised a little from the floor for that purpose) to
warm the spirits, but not so as to cause them to boil. Stop the
aperture at the top and after eight or ten minutes (which time should
be allowed for the vapour to expel the atmospheric air, which
otherwise would cause an explosion) apply the flame of a lamp to the
pierced lines;--in an instant, all the lines will be covered with
flame, which will continue till the spirits are exhausted.
83. TO PRODUCE FLAME OF VARIOUS COLOURS.--This may be effected by
mixing certain substances with burning alcohol, or by applying them
with the point of a pen-knife, to the wick of a burning lamp or
candle. Thus a beautiful rose or carmine coloured flame may be
produced by muriate of strontia: this is prepared by dissolving
carbonate of strontia in muriatic acid, and evaporating it to dryness.
The preparation for an orange colour, is muriate of lime; (a solution
of marble in muriatic acid, evaporated to crystallization) which
should be exposed to a moderate heat till it is deprived of its water
of crystallization and falls to powder. A fine green tinge is produced
by acetate of copper, or boracic acid; which last is procured by
adding sulphuric acid to a solution of borate of soda (in hot water)
till it has a sensibly acid taste; as it cools, the boracic acid is
deposited in crystals on the sides of the vessel. Camphor gives to
flame a blue colour; and nitrate of strontia (prepared the same as the
muriate) a purple. A brilliant yellow may also be produced by muriate
of soda. Any of these preparations being reduced to powder, may be
ignited with three or four times their weight of alcohol, which should
be previously warmed; and if the vessel that contains it be kept
heated also, the combustion will be the more brilliant.