Miscellanies. 379 



The third is the base of the sulphuretted sulphocyanic acid of Ber- 

 zelius, a yellow compound obtained by heating sulphur in prussic acid 

 and vapor. — Idem. 



11. Magnesium. — Bussy* has obtained this metal in the form of a 

 brown metallic powder, not oxidizing by a contact with air, water or 

 dilute nitric acid, but dissolving in caustic potash and muriatic acid, 

 and at a high temperature burning with a residue of magnesia. He 

 prepares it by passing potassium in vapor over dry chloride of mag- 

 nesium. — Idem. 



12. Fulminating Silver. — f Mitscherlich's mode of preparing this 

 substance is very simple. He dissolves a silver salt in caustic ammo- 

 nia to saturation, and adds caustic potash in excess. The fulminating 

 silver falls immediately, and more is obtained by heating till the am- 

 monia is driven off. — Idem, 



13. Red Lead. — This substance is generally supposed to be a mix- 

 ture of protoxide and peroxide of lead in variable proportions. " In 

 some very beautiful red lead," says Dr. Thomson " I have found the 

 proportion of protoxide amount to nearly one half of the whole 

 weight. Acetic acid dissolves out the protoxide and leaves the per- 

 oxide untouched." Fischer has shown that red lead dissolves in con- 

 centrated acetic acid, giving a clear colorless solution, which in a close 

 vessel undergoes no change. Water decomposes it, and throws down 

 the brown oxide. " I have repeated this experiment," says Berzelius, 

 " and find that a small quantity of acid converts the minium into a col- 

 orless salt; a larger quantity dissolves it. Heat throws down the 

 brown oxide without previous dilution. This seems to show that red 

 lead is not, as some have supposed a compound of two oxides." If 

 so, it will be the sesqui-oxide of lead. — Idem. 



14. Fusibility of Salts. — A. mixture of five parts carbonate of pot- 

 ash and four carbonate of soda, melts more easily than either separately. 

 Mitscherlich has applied this to the decomposition of mineral substan- 

 ces, which takes place with such ease in this mixture, that as much as 

 two hundred and twenty grains may be melted over the flame of a 

 lamp. Sand thrown into it in small portions dissolves immediately 

 with evaporation, exactly as when an acid is poured upon an al- 

 kali. — Idem. 



Journal de Chimie Medicale, IV. 856. 

 Poggendorfs Annals, XII. p. 143. 



