480
ELEMENTS OF MATERIA MEDICA.
according to the view taken of the constitution of the resulting com-pound. Sal ammoniac (hydrochlorate of ammonia), but no mercury, iscertainly left in solution, so that the precipitate cannot contain so muchchlorine as bichloride of mercury. It is probable, therefore, that the
mercury from which the chlorine has been removed becomes oxidized
by the water, though, according to Dr. Kane {Trans. Royal Irish Acad.xvii. 423,) this does not take place. The binoxide of mercury, with somemercurial bichloride, and ammonia, precipitate in combination. Thefollowing diagram explains the changes according to this view:—
REAGENTS.
RESULTS.
2eq.Hydrochlr p .Ammonia 108
2 eq. Hydr. "2 eq. Oxyg.
2 eq. Water.. 18
2eq .Hydros Acid. 74
2eq .Ammonia... 342Ammonia... 34
*eq. Ammonia.
1 eq. Bichloride $ 2 eq.
l.Chlor. 72'
Mercury 274 £ 1 eq.
eq. Merc. 202-
1
1 eq. Bichloride Mercury.
leq.Amm.Chlor.Mercury ..526
If we suppose two equivalents or 18 parts of water to be given out byone equivalent or 526 parts of ammonio-cliloridc of mercury, the residuewill have the precise elementary composition assigned by Dr. Kane towhite precipitated mercury.
Properties. —It occurs in commerce in masses or in powder. It iswhite, inodorous, has a taste at first earthy, afterwards metallic. It isdecomposed and dissipated by heat, giving out ammonia, nitrogen,calomel, and water. It is insoluble in alcohol. By boiling in water weobtain a solution of hydrochlorate of ammonia, and a yellow powder(white precipitated mercury and binoxide of mercury.— Kane.) It issoluble in sulphuric, nitric, or hydrochloric acid.
Characteristics. —When heated with caustic potash, it gives outammonia, and forms a yellow powder (white precipitated mercury andbinoxide of mercury,— Kane). The solution contains chloride of potas-sium, and with nitrate of silver causes a white precipitate (chloride ofsilver), insoluble in nitric acid, but soluble in ammonia. Protochlorideof tin decomposes white precipitated mercury, and separates metallicmercury. To these characters must be added the effect of heat, water,and acids, on it, as above mentioned.
Composition. — The analyses of Mr. Hennell {Quart. Journ. ofScience, xviii. 297) and Mitscherlich (Ann. Chim. xxxv. 428), agreein showing the constituents of white precipitate to be those of binoxideof mercury and hydrochlorate of ammonia, in the following propor-tions :—
Eq. Eq.Wt. Per Cent. Hennell.
Mitscherlich.. . . 82-2
Binoxide of Mercury.1 . . . . 218 .... 80-14 .... 80
Hydrochloric Acid.I . . . .
Ammonia.I . . . .
White Precipitate
100*0
272 ... . 99-99 .... 100