480 
gave great satisfaction. Not a trace of vapour was lost and by adding 
every time weighed quantities of Snl, or I and starting from the 
pure components or of a mixture of known composition, a whole 
series of determinations could be carried out. 
The temperature was recorded by means of a previously stand- 
ardised thermo-couple of silver-constantan which was plunged into the 
boiling liquid. 
The results are united in the following table. 
— 
Composition of the liquid. 
gr. Snl, per | at. Sn per | Dane 
100 gr. Snl,-++1 100 at. SnHl | 
0 0 |< 183 
10 2.02 | 184 
20 | 4.04 187 
30 | 6.05 190 
40 | 8.06 | 193 
50 | 10.06 198 
60 | 12.06 | 204 
70 14.05 | 214 
75 | 15.05 | 219 
80 | 16.04 | 228 
85 17.03 | 240 
90 18.02 P eee7 
95 | 19.01 296 
100 20.00 | 340 
9. Finally, we endeavoured to determine the composition of the 
saturated vapour which coexists with the different Sn 1, — I mixtures. 
For this purpose the liquid was heated to boiling in a 25 c.m. 
long circular tube surrounded at its upper end by a thick asbestos 
jacket. In the vapour space was then placed a long suction tube 
with a pipette-like enlargement of 1—2 cc, capillarily drawn out 
and bent upwards at the lower end. By means of this tube some 
vapour close above the surface of the boiling liquid was withdrawn ; 
this condensed for the greater part in the pipette and was then 
