318 NOTES. 
mould is artists’ modeling-wax, which is a composition akin to 
that used by dentists ; and, as it becomes soft and plastic by the 
application of heat, though in a cold state it is perfectly rigid, it 
may be applied to the most delicate object without injury. As it 
takes the most minute markings and striations of the original to 
which it is applied, the microscopic structure of the surface of the 
- original is faithfully reproduced in the cast. This method is briefly 
this: 1. Cover the object to be cast with a thin powder of steatite 
or French chalk, which prevents the adhesion of the wax.. 2. Af- 
ter the wax has become soft, either from immersion in warm water, 
or from exposure to the direct heat of the fire, apply it to the orig- 
inal, being careful to press it into the little cavities. Then care- 
fully cut off the edges of the wax all round, if the undercutting of 
the object necessitates the mould being in two or more pieces, and 
let the wax cool with the object in it, until it is sufficiently hard 
to bear the repetition of the operation on the uncovered portion 
of the object. The steatite prevents the one piece of the mould 
sticking to the other. The original ought to be taken out of the 
mould before the latter becomes perfectly cold and rigid, as in that 
case it is very difficult to extract. 3. Then pour in plaster of 
Paris, after having wetted the moulds to prevent bubbles of air 
lurking in the small interstices; and, if the mould be in two 
pieces, it is generally convenient to fill them with plaster sepa- 
rately before putting them together. 4. Then dry the plaster 
casts either wholly or partially. 5. Paint the casts in water-col- 
ors, which must be fainter than those of the original, because the 
next process adds to their intensity. The delicate shades of color 
in the original will be marked in the cast by the different quantity 
of the same color, which is taken up by the different textures of 
the cast. 6. After drying the cast, steep it in hard paraffine. 
The ordinary paraffine candles, which can be obtained from any 
grocer, will serve the purpose. 7. Cool, and polish the cast by 
hand with steatite. The result of this process is said to be far 
better than that obtained by any other.— The Manufacturer and 
Builder. 
The American Museum of Natural History held an exhibition 
of its collections in the Arsenal building, in the Central, Park, to 
invited guests, April 27th. This Association was incorporated 
some two years since, and has made excellent progress in estab- 
lishing a museum. The cases are said to contain nearly one thou- 
ERME i AA A ee er A A 
ESNE PNIL EATA E N 
ee ace ee E E T 
