Of Copying By Moulding





112. This method of producing multitudes of individuals

having an exact resemblance to each other in external shape, is

adopted very widely in the arts. The substances employed are,

either naturally or by artificial preparation, in a soft or

plastic state; they are then compressed by mechanical force,

sometimes assisted by heat, into a mould of the required form.



113. Of bricks and tiles. An oblong box of wood fitting upon

a bottom fixed to the brickmaker's bench, is the mould from which

every brick is formed. A portion of the plastic mixture of which

the bricks consist is made ready by less skilful hands: the

workman first sprinkles a little sand into the mould, and then

throws the clay into it with some force; at the same time rapidly

working it with his fingers, so as to make it completely close up

to the corners. He next scrapes off, with a wetted stick, the

superfluous clay, and shakes the new-formed brick dexterously out

of its mould upon a piece of board, on which it is removed by

another workman to the place appointed for drying it. A very

skilful moulder has occasionally, in a long summer's day,

delivered from ten to eleven thousand bricks; but a fair average

day's work is from five to six thousand. Tiles of various kinds

and forms are made of finer materials, but by the same system of

moulding. Among the ruins of the city of Gour, the ancient

capital of Bengal, bricks are found having projecting ornaments

in high relief: these appear to have been formed in a mould, and

subsequently glazed with a coloured glaze. In Germany, also,

brickwork has been executed with various ornaments. The cornice

of the church of St Stephano, at Berlin, is made of large blocks

of brick moulded into the form required by the architect. At the

establishment of Messrs Cubitt, in Gray's Inn Lane, vases,

cornices, and highly ornamented capitals of columns are thus

formed which rival stone itself in elasticity, hardness, and

durability.



114. Of embossed china. Many of the forms given to those

beautiful specimens of earthenware which constitute the equipage

of our breakfast and our dinner-tables, cannot be executed in the

lathe of the potter. The embossed ornaments on the edges of the

plates, their polygonal shape, the fluted surface of many of the

vases, would all be difficult and costly of execution by the

hand; but they become easy and comparatively cheap, when made by

pressing the soft material out of which they are formed into a

hard mould. The care and skill bestowed on the preparation of

that mould are repaid by the multitude it produces. In many of

the works of the china manufactory, one part only of the article

is moulded; the upper surface of the plate, for example, whilst

the under side is figured by the lathe. In some instances, the

handle, or only a few ornaments, are moulded, and the body of the

work is turned.



115. Glass seals. The process of engraving upon gems requires

considerable time and skill. The seals thus produced can

therefore never become common. Imitations, however, have been

made of various degrees of resemblance. The colour which is given

to glass is, perhaps, the most successful part of the imitation.

A small cylindrical rod of coloured glass is heated in the flame

of a blowpipe, until the extremity becomes soft. The operator

then pinches it between the ends of a pair of nippers, which are

formed of brass, and on one side of which the device intended for

the seal has been carved in relief. When the mould has been well

finished and care is taken in heating the glass properly, the

seals thus produced are not bad imitations; and by this system of

copying they are so multiplied, that the more ordinary kinds are

sold at Birmingham for three pence a dozen.



116. Square glass bottles. The round forms which are usually

given to vessels of glass are readily produced by the expansion

of the air with which they are blown. It is, however, necessary

in many cases to make bottles of a square form, and each capable

of holding exactly the same quantity of fluid. It is also

frequently desirable to have imprinted on them the name of the

maker of the medicine or other liquid they are destined to

contain. A mould of iron, or of copper, is provided of the

intended size, on the inside of which are engraved the names

required. This mould, which is used in a hot state, opens into

two parts, to allow the insertion of the round, unfinished

bottle, which is placed in it in a very soft state before it is

removed from the end of the iron tube with which it was blown.

The mould is now closed, and the glass is forced against its

sides, by blowing strongly into the bottle.



117. Wooden snuff boxes. Snuff boxes ornamented with devices,

in imitation of carved work or of rose engine turning, are sold

at a price which proves that they are only imitations. The wood,

or horn, out of which they are formed, is softened by long

boiling in water, and whilst in this state it is forced into

moulds of iron, or steel, on which are cut the requisite

patterns, where it remains exposed to great pressure until it is

dry.



118. Horn knife handles and umbrella handles. The property

which horn possesses of becoming soft by the action of water and

of heat, fits it for many useful purposes. It is pressed into

moulds, and becomes embossed with figures in relief, adapted to

the objects to which it is to be applied. If curved, it may be

straightened; or if straight, it may be bent into any forms which

ornament or utility may require; and by the use of the mould

these forms may be multiplied in endless variety. The commoner

sorts of knives, the crooked handles for umbrellas, and a

multitude of other articles to which horn is applied, attest the

cheapness which the art of copying gives to the things formed of

this material.



119. Moulding tortoise-shell. The same principle is applied

to things formed out of the shell of the turtle, or the land

tortoise. From the greatly superior price of the raw material,

this principle of copying is, however, more rarely employed upon

it; and the few carvings which are demanded, are usually

performed by hand.



120. Tobacco-pipe making. This simple art is almost entirely

one of copying. The moulds are formed of iron, in two parts, each

embracing one half of the stem; the line of junction of these

parts may generally be observed running lengthwise from one end

of the pipe to the other. The hole passing to the bowl is formed

by thrusting a long wire through the clay before it is enclosed

in the mould. Some of the moulds have figures, or names, sunk in

the inside, which give a corresponding figure in relief upon the

finished pipe.



121. Embossing upon calico. Calicoes of one colour, but

embossed all over with raised patterns, though not much worn in

this country, are in great demand in several foreign markets.

This appearance is produced by passing them between rollers, on

one of which is figured in intaglio the pattern to be transferred

to the calico. The substance of the cloth is pressed very

forcibly into the cavities thus formed, and retains its pattern

after considerable use. The watered appearance in the cover of

the volume in the reader's hands is produced in a similar manner.

A cylinder of gun-metal, on which the design of the watering is

previously cut, is pressed by screws against another cylinder,

formed out of pieces of brown paper which have been strongly

compressed together and accurately turned. The two cylinders are

made to revolve rapidly, the paper one being slightly damped,

and, after a few minutes, it takes an impression from the upper

or metal one. The glazed calico is now passed between the

rollers, its glossy surface being in contact with the metal

cylinder, which is kept hot by a heated iron enclosed within it.

Calicoes are sometimes watered by placing two pieces on each

other in such a position that the longitudinal threads of the one

are at right angles to those of the other, and compressing them

in this state between flat rollers. The threads of the one piece

produce indentations in those of the other, but they are not so

deep as when produced by the former method.



122. Embossing upon leather. This art of copying from

patterns previously engraved on steel rollers is in most respects

similar to the preceding. The leather is forced into the

cavities, and the parts which are not opposite to any cavity are

powerfully condensed between the rollers.



123. Swaging. This is an art of copying practised by the

smith. In order to fashion his iron and steel into the various

forms demanded by his customers, he has small blocks of steel

into which are sunk cavities of different shapes; these are

called swages, and are generally in pairs. Thus if he wants a

round bolt, terminating in a cylindrical head of larger diameter,

and having one or more projecting rims, he uses a corresponding

swaging tool; and having heated the end of his iron rod, and

thickened it by striking the end in the direction of the axis

(which is technically called upsetting), he places its head upon

one part of the lage; and whilst an assistant holds the other

part on the top of the hot iron, he strikes it several times with

his hammer, occasionally turning the head one quarter round. The

heated iron is thus forced by the blows to assume the form of the

mould into which it is impressed.



124. Engraving by pressure. This is one of the most beautiful

examples of the art of copying carried to an almost unlimited

extent; and the delicacy with which it can be executed, and the

precision with which the finest traces of the graving tool can be

transferred from steel to copper, or even from hard steel to soft

steel, is most unexpected. We are indebted to Mr Perkins for most

of the contrivances which have brought this art at once almost to

perfection. An engraving is first made upon soft steel, which is

hardened by a peculiar process without in the least injuring its

delicacy. A cylinder of soft steel, pressed with great force

against the hardened steel engraving, is now made to roll very

slowly backward and forward over it, thus receiving the design,

but in relief. The cylinder is in its turn hardened without

injury., and if it be slowly rolled to and fro with strong

pressure on successive plates of copper, it will imprint on a

thousand of them a perfect facsimile of the original steel

engraving from which it was made. Thus the number of copies

producible from the same design may be multiplied a

thousand-fold. But even this is very far short of the limits to

which the process may be extended. The hardened steel roller,

bearing the design upon it in relief may be employed to make a

few of its first impressions upon plates of soft steel, and these

being hardened become the representatives of the original

engraving, and may in their turn be made the parents of other

rollers, each generating copperplates like their prototype. The

possible extent to which facsimiles of one original engraving may

thus be multiplied, almost confounds the imagination, and appears

to be for all practical purposes unlimited.



This beautiful art was first proposed by Mr Perkins for the

purpose of rendering the forgery of bank notes a matter of great

difficulty; and there are two principles which peculiarly adapt

it to that object: first, the perfect identity of all the

impressions, so that any variation in the minutest line would at

once cause detection; secondly, that the original plates may be

formed by the united labours of several artists most eminent in

their respective departments; for as only one original of each

design is necessary, the expense, even of the most elaborate

engraving, will be trifling, compared with the multitude of

copies produced from it.



125. It must, however, be admitted that the principle of

copying itself furnishes an expedient for imitating any engraving

or printed pattern, however complicated; and thus presents a

difficulty which none of the schemes devised for the prevention

of forgery appear to have yet effectually obviated. In attempting

to imitate the most perfect banknote, the first process would be

to place it with the printed side downwards upon a stone or other

substance, on which, by passing it through a rolling-press, it

might be firmly fixed. The next object would be to discover some

solvent which should dissolve the paper, but neither affect the

printing-ink, nor injure the stone or substance to which it is

attached. Water does not seem to do this effectually, and perhaps

weak alkaline or acid solutions would be tried. If, however, this

could be fully accomplished, and if the stone or other substance,

used to retain the impression, had those properties which enable

us to print from it, innumerable facsimiles of the note might

obviously be made, and the imitation would be complete. Porcelain

biscuit, which has recently been used with a black lead pencil

for memorandum books, seems in some measure adapted for such

trials, since its porosity may be diminished to any required

extent by regulating the dilution of the glazing.



126. Gold and silver moulding. Many of the mouldings used by

jewellers consist of thin slips of metal, which have received

their form by passing between steel rollers, on which the pattern

is embossed or engraved; thus taking a succession of copies of

the devices intended.



127. Ornamental papers. Sheets of paper coloured or covered

with gold or silver leaf, and embossed with various patterns, are

used for covering books, and for many ornamental purposes. The

figures upon these are produced by the same process, that of

passing the sheets of paper between engraved rollers.





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