476 
Composition of the liquid | 
| Initial 
gr. Snl4 per | at. Sn per | Solidifying point 
100 gr. Snl4 +1 | 100 at. Sn 41 || 
0 0 113.2 
10 202 109.0 
20 4.04 104.7 
30 6.05 99.7 
40 8.06 94.7 
50 10.06 | 87.6 
55 11.06 | 83.0 
60 12.06 | 719.6 
65 13.05 83.5 (eutecticum 79°.6) 
70 14.05 89.8 
80 16.04 108.4 
90 18.02 127.0 
100 20.00 143.5 
Sn I, might not really be in stable equilibrium with each other 
and that Sn I, might be at high temperature a labile compound that 
would dissociate into Sn + Sn [,. Looking at the fact that the number 
of halogen atoms, capable of combining with an element, generally 
decreases with the atomic weight of the halogen, the probability of 
this was not great, and it was even to be expected that Snl, would 
be very permanent. 
In order to decide this, weighed quantities of Sn, SnI,, and Sn I, 
were heated in a sealed tube during 14 hours at 360°. Starting from 
12.5 grams of SnI,, 7.7 grams of Sn I, and 2.4 grams of Sn there 
were obtained about 9.6 grams of SnI,, 10.5 grams of Sn I, and 
1.6 gram of Sn. Consequently, there was a very appreciable decrease 
of Sn and Sn I, and an increase of Sn I,. 
The reaction Sn + Snl,-—2Snl,, therefore, actually does take 
place, although very slowly. The contradiction between the statement 
of Personne that from Sn + I no Sn l, is formed and that of Henry, 
who states that a mixture of SnI, and Snl, is formed, is now 
explained. Herry has evaporated SnI, with an excess of fine tin 
powder and so obtained a partial conversion into Sn I, which was 
