266 Scientific Intelligence. 
II. Arts. 
1. Artificial Marble, (Journ. de Chem. Med., April, 1846, p. 299.)— 
M. Bouisson has taken out a patent for preparing artificial marble from 
gypsum, which is to be cut of the required size, placed in a metallic 
trough in a furnace, and kept at the temperature of 90° for some time, 
after whieh a solution of alum in boiling water is poured upon it and 
a gentle heat continued for some length of time, the water being re- 
newed as it evaporates. Fora block six feet long and two feet in the 
other directions, exposure for five hours before the addition of alum 
solution, and seventy-two hours after, suffice to impregnate the plaster. 
The strength of the alum solution is one pound to six quarts of water. 
It is always well to cut the plaster in the form required before harden- 
ing it. By introducing colormg matter into the solution, various tints 
J. Tae. 
may be obtained. 
2. Preparation of a Substitute for Horn ; by M. Rocuon, (Voigt. 
Mag. de Naturk. and Revue Scient:, Feb., 1846, p. 256.)—In many of 
the arts, more especially where neal instruments are manufactured, 
glass windows are of great inconvenience owing to the frequent break- 
age by fragments of steel. The substitution of horn is attended with 
some inconvenience, principally on account of its want of transparency. 
A substitute is proposed to be made of very light cloth or wire gauze 
composed of fine brass wire, which is to be immersed repeatedly into 
a solution of isinglass until all the meshes are filled and a sufficient 
thickness acquired, after which it is covered with a coat of copal or 
wo varnish to protect it from the weather. 3 meee J. L. 8. 
3. Amalgamation ‘of Wrought Iron, Cast Iron and Steel, so as to 
prepare them for Fire Gilding ; by R. Borrrarr, (Poggend. Am., 1846, 
No. 1, and Bib. Univer., March, 1846, p. 201.)—Place in a glazed 
earthen ware or porcelain vessel 12 parts by weight of mercury, 1 of 
zinc, 2 of sulphate of iron, 12 of water, and 14 of hydrochloric acid 
of 1:2 sp. grav.; then introduce the iron or steel into the mixture, 
which is to be heated to ebullition. In a little time the objects become 
covered with a thin coating of mercury; which enables us to apply 
immediately, the amalgam of gold that is used in the gilding. All 
that is now necessary, is to apply a strong heat which will drive off the 
‘Mercury and the trace of zine that may have attached itself to the iron, 
leaving a surface of pure gold. By the ordinary way, it becomes neces- 
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