RESULTS OF PHYSICAL AND CHEMICAL INVESTIGATIONS. 
7a 
valents of stannous chloride and aniline; combination occurs with a gentle disengagement 
of heat, and at the end of several hours a crystalline mass is obtained, slightly soluble in 
cold water and in alcohol, but which is decomposed by warm liquids. 
The hydrochlorate of stannicanile (C 24 HjoSnNo,2 HC1) results from the union of two 
equivalents of aniline, and one of stannic chloride. An intense heat is produced at the 
moment of admixture, and it is necessary, to avoid explosions, to surround the vessel by a 
freezing mixture. Under these conditions a perfectly white crystalline mass is obtained. 
A more advantageous method however may be employed, depending on the curious pro¬ 
perty of certain metallic perchlorides of dissolving in benzol. If aniline be added drop 
by drop to a solution of perchloride of tin in benzol, a white crystalline powder is soon 
deposited, consisting of the hydrochlorate of stannicanile, which is insoluble in benzol. 
Water decomposes this salt, precipitating stannic hydrate. It can only be fused in very 
small quantities without decomposition. When some quantity is heated it undergoes a 
transformation, giving rise to the production of rosaniline (magenta). M. Schiff considers 
that iu the manufacture of this dye, by the action of chloride of tin on aniline, this com¬ 
pound is always first formed. He finds that during the production of rosaniline by the 
decomposition of the hydrochlorate of stannicanile, the tin is reduced to stannous 
chloride, a certain quantity of aniline is set free, and a considerable quantity of a white 
sublimate is produced, consisting of a mixture of the hydrochlorates of aniline and am¬ 
monia. He represents the change therefore as consisting of 10 equivalents of hydrochlorate 
of stannicanile breaking up into 3 equivalents of hydrochlorate of rosaniline, 6 of hydro¬ 
chlorate of aniline, 1 of sal-ammoniac, 4 of free aniline, and 10 of stannous chloride. At 
the same time, he allows that in the manufacturing process other secondary products are 
formed. 
He states that perfectly dry hydrochlorate of stannicanile yields magenta when heated 
in a current of carbonic acid, rigorously deprived of oxygen and moisture ; thus proving 
that neither water nor oxygen are concerned in the reaction, as some have supposed. 
On the Reduction of Ghloride of Silver. —MM. Millon and Commaille have com¬ 
municated to the French Academy an extremely elegant reaction, by which absolutely 
pure metallic silver may be precipitated from its ammoniacal combinations, with all the 
accuracy necessary for rigid analysis, and in such a fine state of division as to render it 
available in the arts. 
The reagent employed is ammonio-subchloride of copper. When this substance is 
added to ammonio-nitrate or ammonio-chloride of silver, the whole of the silver is at 
once thrown down in the metallic state as a grey amorphous precipitate. The precipi¬ 
tate readily assumes a metallic lustre under the burnisher, and may be applied to the 
surfaces of wood, stone, etc. The reaction takes place so perfectly, that it may be em¬ 
ployed either for the estimation of silver, or for, the analysis of a mixture of sub- and 
protosalt of copper; every atom of silver thrown down representing one atom of sub¬ 
chloride of copper. 
It is however especially valuable for reducing the chloride of silver residues of the 
laboratory. These are dissolved in ammonia, and the ammoniacal subchloride of copper 
added, when the metallic silver is at once obtained in a state of absolute purity. More¬ 
over, it is only necessary to digest the filtrate with a little powdered zinc in a closed 
flask, in order to again reduce the copper salt, and it is ready for a fresh operation. In 
this way, the same quantity of copper solution suffices for an indefinite number of preci¬ 
pitations. 
On the Preparation of Acetic Anhydride. —M. H. Gal has pointed out that 
when chloride of acetyl is treated with a metallic oxide decomposition occurs, a chloride 
of the metal and acetic anhydride being formed. When the chloride of acetyl is poured 
on finely pulverized caustic lime, the reaction is very energetic; the lime becoming in¬ 
candescent when considerable quantities are employed. With oxide of lead, on the other 
hand, the action is very sluggish; but with caustic baryta it is rapid, and at the same 
time very manageable. If equal equivalents of chloride of acetyle and caustic baryta 
are sealed up in a tube, the action commences in the cold, and may be completed by a 
few hours’ digestion in a water-bath. Upon afterwards distilling the contents of the 
tube, the temperature rapidly rises to 137°, and then remains stationary. The. liquid 
which then passes over consists of anhydrous acetic acid. The following equation re¬ 
presents the change which occurs:— 
