200 Miscellanies. 
is difficult to isolate this compound, but it is easily obtained in combination 
under the form of osmiamide. Its compound with hydrochlorate of am- 
monia is procured by adding together solutions of this salt and osmite 
of potash, when a yellow precipitate is formed having for its formula 
Os O? Az H?++-HCl Az H®. 
Hydrosulphite of Soda, by M. Punssy, (Ann. de Chim. et de Phys. 
June, 1844, p. 182.)—The author first prepares the bisulphite of soda by 
passing a current of sulphurous acid through a solution of carbonate of 
soda, until the acid is no longer dissolved. This bisulphite is converted 
into sulphite by adding carbonate of soda until effervescence ceases ; the 
liquid is now boiled with flowers of sulphur for fifteen or twenty minutes, 
stirring frequently ; then separate from the excess of sulphur, evaporate 
to the consistency of syrup, and allow it to stand. If there should hap- 
pen to be any sulphate present it separates. After twenty four hours the 
clear liquid is decanted, concentrated, and allowed to crystallize. 
Xanthic Oride in Guano. (Chem. Gazette, Aug. 1844, p. 363.)—M. 
Unger has discovered the presence of this substance in guano. ‘Treat 
the guano with hydrochloric acid, precipitate with caustic potash, which 
redissolves a small portion of the precipitate, (the oxide in question ;) to 
separate it from the potash, all that is necessary to do is to pass a current 
of carbonic acid through the solution, or by the addition of hydrochlorate 
of ammonia, when it deposits as the ammonia evaporates. 
To detect the presence of Sugar in Diabetic Urine, by Dr. Carrezvoul, 
(Gaz. Toscan. and Chem. Gaz. Aug. 1844, p. 369.)—The fresh urine is 
placed in a cylindrical vessel, and to it added a few grains of the hydra- 
ted oxide of copper, and enough of a solution of caustic potash to render 
the urine alkaline; the whole is shaken together, when it becomes troub- 
led from the precipitation of the phosphates, and from the oxide of cop- 
per which it contains in suspension. ‘The urine gradually becomes clear 
from the subsidence of the voluminous deposit, which is at first of a sky- 
blue color, but at the end of a few hours a canary-yellow circle is seen to 
form on its surface, and gradually to pervade the mass; subsequently @ 
red color more or less deep in the form of a zone replaces the yellow 
either wholly or in part. This phenomenon, which is generally complet- 
ed in twenty four hours, is owing to the reaction of the sugar on the ox- 
ide of copper, which is gradually deprived of its oxygen. If the reac- 
tion does not appear in twenty four hours a little potash will develope it. 
Carbonate of Ammonia and Magnesia, and Carbonate of Ammonia 
and Zinc, by M. Favre, (Ann. de Chim. et de Phys. April, 1844, p- 
474.)—Both are formed by agitating the carbonate of ammonia with the 
respective carbonates recently prepared, when the filtered solutions will 
deposit crystals of the double salts, unalterable in well corked phials. 
Formule, CO? MgO+CO? NH‘ 0-4-4 Aq. 
CO? Zn O+-CO2 NH¢4 O--4 Aq. 
