Chemical Properties of Stannic Chloride. 393 



- V. The Effect of Absolute Alcohol on the Tetrachloride 

 saturated with Sulphuretted Hydrogen. — Incidentally, in de- 

 scribing the effect of sulphuretted hydrogen on the alcoholic 

 and ethereal solutions of stannic chloride, I was compelled to 

 state some of the results which would naturally have fallen 

 under this heading. It has been recorded : — 



(1) That stannic chloride saturated with sulphuretted hy- 

 drogen does not conduct. 



(2) That a mere film of absolute alcohol adhering to one 

 electrode is sufficient to endow such a solution with some 

 conductivity. 



To amplify (2) : the actual deflexion observed was forty 

 scale-divisions. On pouring a little alcohol down one arm of 

 the cell the conductivity increased so that a 150 scale-division 

 deflexion was registered. Directly the alcohol reached the 

 solution there was a vigorous interaction and stannic sulphide 

 was precipitated. After a similar quantity had been added to 

 the other arm and the cell shaken, the current through the 

 galvanometer was sufficiently great to turn the mirror at 

 right angles to its original position. 



Class C. The Effect of Solids on the Conductivity of the 

 Tetrachloride. 

 The endeavour to destroy the chemical homogeneity of the 

 stannic chloride was a failure, owing to the insolubility of the 

 solids that were tried. Attempts were made with 



(1) The crystalline hydrate, 



SnCl 4 . 5H 2 0. 



(2) The crystalline sulphydrate, 



SnCl 4 .5H 2 S. 



(3) Dry sodium chloride. 



(4) Moist sodium chloride. 



(5) The double ammonium stannic chloride. 



After failing to obtain other than a negative result with 

 sodium chloride, it seemed possible that if the chloride of the 

 alkaline metal was first combined with stannic chloride the 

 double salt might dissolve. The success that Moissan enjoyed 

 by adding to the liquid hydrofluoric acid, the double potassium 

 hydrogen fluoride, suggested this attempt. Some quantity of 

 the double ammonium stannic chloride, (2NH 4 C1 . SnCl 4 ), was 

 prepared according to the directions given by Bongartz and 

 Classen (Ber. xxi. p. 290), who determined the atomic weight 

 of tin by electrolysing a solution of this salt in the acid am- 

 monium oxalate. The double chloride was perfectly dried by 

 standing over phosphorus pentoxide in a desiccator. A gram 

 of this dry salt was added to the stannic chloride in the V-tube. 

 Phil. Mag. S. 5. Vol. 29. No. 180. May 1890. 2 H 



