MISCELLANY. 
On the Employment of Guaiacum-resin as a test. By G. Osann. — Ac- 
cording to Schonbein, guaiacum-resin is coloured blue by ozone; the 
same alteration is also effected by chlorine. This circumstance can 
be turned to account for detecting very feeble electric^ currents, by 
passing them through a mixture of a few drops of tincture of guaiacum 
and common salt. The guaiacum solution, however, should always 
be recently prepared. 
The solution of guaiacum is extremely sensitive towards perchloride 
of iron, so that when present in so small a proportion as not to act 
upon tincture of galls, it still colours the solution of guaiacum blue. — 
Chem. Gaz.from Poggcndorjfs Annalen. 
A new mode of preserving Animal Substances. By the Abbe Bal- 
daumik. — The Abbe Baldaumik, preparator at the Museum of Natu- 
ral History at Vienna, has succeeded in rendering animal substances 
as hard as stone. To effect this he immerses them in water, holding 
in solution bichloride of mercury and hydrochlorate of ammonia. 
Substances that have remained immersed in this liquid for some time 
acquire the hardness of stone, may be polished, resist the hammer, 
have an angular fracture, and give out a metallic sound when struck. 
They preserve their natural colour, and require no further care after 
they are taken out of the bath. — Chemist, from Archiv. de Pharm. 
On the Preservation of Water. By M. Perinet. — M. Perinet, ex- 
professor of the Hopital Militaire d ' Instruction, has succeeded in pre- 
serving water in a sweet state by placing a kilogramme and a half of 
black oxide of manganese in each cask of water containing 250 litres. 
He has kept this water for seven years in the same barrels, and ex- 
posed them to various temperatures; at the end of that time he found 
it as limpid, free from smell, and of as good quality as at the begin- 
ning of the experiment. — Ibid, from Journ. de Chim. 
