312 
C A S 
C AS 
CAS 
p irately, and afterwards to join them toge- 
ther. In this case, the p 'mister must be tem- 
pered witii water to such a consistence, that 
it may be worked like suit paste, and must be 
laid on witii some convenient instrument, 
compressing it so as to make it adapt itself 
to all parts of the surface. When the model 
is covered to a convenient thickness, the 
whole must be "left at rest till the plaister is 
set and l:rm, so as to bear dividing without 
fading to pieces, or being liable to be put 
out ot its form bv any slight violence ; and 
it must then be div ided into pieces, in order 
1;o its being taken off from the model, by 
cutting it with a knife with a very thin blade ; 
and being divided, must be cautiously taken 
oh, and kept till dry : but it must be observed, 
before the separation of the parts is made, 
to notch them across the joints, or lines of 
division, at proper distances, that they 
may with ease and certainty be properly 
put together again. The art of properly 
dividing the moulds, in order to make them 
separate from the model, requires more dex- 
terity and skill tlun any other thing in the 
art of casting, and does not admit of rules 
for the most advantageous conduct of it in 
every case. Where the subject is of a round 
or spheroidal form, it is best to divide the 
mould into three parts, which will then easily 
come off from -the model ; and the same will 
hold good of a cylinder, or any regular curve 
figure. The mould being thus, formed, and 
dry, and the parts put together, it must be 
first oiied, and placed in such a position that 
the hollow may lie upwards, and then filled 
with plaister mixed with water ; and when 
the cast is perfectly set and dry, it must 
be taken out of the mould and repaired 
when necessary, which finishes the opera- 
tion. 
In larger masses, where there would other- 
wise be a great thickness of the plaister, a 
core may be put within the mould, in order 
to produce a hollow in the cast, which both 
saves the expence of the plaister, and ren- 
ders the cast lighter. 
In the same manner, figures, busts, &c. 
may be cast of lead, or any other metal in 
the moulds of plaister or clay r ; taking care, 
however, that the moulds be perfectly dry ; 
for, should there be the least moisture in them, 
the sudden heat of the metal would convert 
it into vapour, which would produce an ex- 
plosion, and blow the melted metal about. 
To take a cast in metal from any small 
animal, insect, or vegetable. — Prepare a box 
sufficiently large to hold the animal (which 
must be dead), in which it must be suspended 
by a string, and the legs, wings, Sec. of the ani- 
mal, or the tendrils, leaves. Sec. of the vegeta- 
ble, must be separated, and ■adjusted in their 
right position by a pair of small piucers. A due 
quantity of plaister of Paris mixed with talc, 
must be tempered to the proper consistence 
with water, and the sides of the box oiled. Also 
a straight piece of stick must be put to the 
principal part of the body, and pieces of wire 
to the extremities of the other parts, in order 
that they may form, when drawn out after 
the matter of the mould is set .and firm, pro- 
per channels for pouring in the metal, and 
vents for the air, which otherwise, by the 
rarefaction it would undergo from the heat 
of the metals, would blow it out, or burst the 
mould. In a short time the plaister will set, 
jand become hard ; when the stick and wires 
may be drawn out, and the frame or coffin 
in which the mould was cast taken away ; 
and the mould must then be put, first, into 
a moderate' heat, and afterwards, when it is 
as dry as it can be rendered by that degree, 
removed into a greater, w hich may be gradu- 
ally increased tiii the whole is red-hot. The 
animal or vegetable inclosed in the mould, will 
then be burnt to a coal: and may be totally 
calcined to ashes, by blowing for some time 
into the charcoal and passages made for pour- 
ing in the metal, and giving vent to the air ; 
which will, at the same time that it destroys 
the remainder of the animal or vegetable 
matter, blow out the ashes. The mould must 
then be suffered to cool gently, and will be 
perfect; the destruction of the substance in- 
cluded in it, having produced a correspond- 
ing hollow ; but it may nevertheless be proper 
to shake the mould, and turn it upside 
down, as also to blow with the bellows 
into each of the air vents, in order to free it 
wholly from any remainder of the ashes ; or 
where there maybe an opportunity of tilling 
the hollow with quicksilver, it will be found 
a very effectual method of clearing the ca- 
vity ; as all dust, ashes, or small detached bo- 
dies, will necessarily rise to the surface of the 
quicksilver, and be poured out with it. The 
mould being thus prepared, it must be heated 
very hot, when used, if the cast is to be 
made with copper or brass, but a less degree 
will serve for lead or tin. The metal being- 
poured into the mould, must be gently 
struck, and then suffered to rest till it is 
cold ; at which time it must be carefully 
taken from the cast, but without force ; for 
such parts of the matter as appear to adhere 
more strongly, must be softened, by soaking 
in water till they are entirely loosened, that 
none of the more delicate parts of the cast may 
be broken off or bent. 
When talc cannot be obtained, plaister 
alone may be used ; but it is apt to be calcined, 
by the heat used in burning the animal or 
vegetable whence the cast is taken, and to 
become of too incoherent and friable a tex- 
ture. Stourbridge, or any other good clav, 
washed perfectly fine, and mixed with an 
equal part Of fine sand, may be employed. 
Pounded pumice-stone, and plaister of Paris, 
in equal quantities, mixed with washed clay 
in the same proportion, is said to make ex- 
cellent moulds. 
Method of taking a cast in plaister from a 
person’s face. — The person whose likeness is 
required in plaister, must lie on his back, 
and the hair must be tied back, so that none 
of it covers the face. Into each nostril con- 
vey a conical piece of stiff paper, open at 
both ends, to allow of breathing. The face 
is then lightly oiled over in every part witii 
salad-oil, to prevent the plaister from sticking 
to the skin. Procure some fresh-burnt plais- 
ter, and mix it with water to a' proper con- 
sistence for pouring. Than pour it by spoon- 
fuls quickly all over the face (taking cafe the 
eyes are shut), till it is entirely covered 
to the thickness of a quarter of an inch. 
This substance will grow sensibly hot, and in 
a few minutes it will be hard, and form a 
mould, in which a head of clay may be 
moulded ; and therein the eyes may be open- 
ed, and such other additions and corrections 
may be made as are necessary. Then, this 
second face being anointed with oil, another 
mould of plaister must be made upon it, con- 
sisting of two parts joined lengthwise along 
the ridge of the nose; and in this a cast in 
plaister may be taken, which will be exactly 
like the original. 
To take casts from medals. — In order 
to take copies of medals, a mould must first 
be made ; this is generally either of plais- 
ter of Paris, or of melted sulphur. 
After having oiled the surface of the 
medal with a little cotton, or a camel’s-hair 
pencil dipped in oil of olives, put a hoop of 
paper round it, standing up above the surface 
of the thickness you wish the mould to be. 
Then take some plaister of Paris, mix it with 
water to the consistence of cream, and 
with a brush rub it over the surface of the me- 
dal, to prevent air-holes from appearing : • 
then immediately afterwards make it to a suf- : 
ficient thickness, by pouring on more plaister. 
Let it stand about half ait hour, and it will ! 
in that time grow so hard, that you may 
safely take it off; then pare it smooth on 
the back and round the edges neatly. It 
should be dried, if in cold or damp weather, 
before a brisk fire. If you cover the face of 
the mould with line plaister, a coarser sort 
will do for the back : but no more plaister 
should be mixed up at one time than can be 
used, as it will soon get hard, and cannot be 
softened without burning over again. Sul- 
phur must not be poured upon silver medals, 
as this will tarnish them. 
To prepare this mould for casting sulphur 
or plaister of Paris in, take half a pint of boiled 
linseed-oil, and oil of turpentine one ounce, 
and mix them together in a bottle; when 
wanted, pour the mixture into a plate or ' 
saucer, and dip the surface of the mould into] 
it ; take the mould out again ; and when it 
lias sucked in the oil, dip it again. Repeat 
this, till the oil begins to stagnate upon it ; 
then take a little cotton wool, hard rolled up, 
to prevent the oil from sticking to it, and wipe 
it carefully off. Lay it in a dry place for a. 
day or two (if longer the better), and the 
mould will acquire a very hard surface from ] 
the effect of the oil. 
To cast plaister of Paris in this mould, pro-| 
ceed with it in the same manner as above di- 
rected for obtaining the mould itself, first oil- 
ing the mould with olive-oik If sulphur casts ) 
are required, it must be melted in an iron ladle.1 
Another method with isinglass’. — Dissolve! 
isinglass in water over the lire ; then, with 
a hair-pencil, lay the melted isinglass over 
the medal; and when you have covered it.: 
properly, let it dry. When it is hard, raise] 
the isinglass up with the point of a pen-knife j 
and it will ily off like horn, having a sharp! 
impression of the medal. 
The isinglass may be made of any colour,] 
by mixing the colour with it ; or you may] 
breathe on the concave side, and lay gold,, 
leaf on it, which, by shining through, will 
make it appear like a gold medal. But if youl 
wish to imitate a copper medal, mix a littlel 
carmine with the isinglass, and lay gold-leaf 
on as before. 
CASTLE, in the sea language, is a part] 
of the ship, of which there are two ; the fore-1 
castle, being the elevation at the prow, or the] 
uppermost deck, towards the mizen, thel 
place where the kitchens are ; and the hind- ] 
castle, where the officers’ cabins are. 
CASTOR, the bearer, in zoology, age-] 
mis of the order of glires. The generic cha-| 
racter is, front teeth in the upper jaw trim A 
