1904 - 5 .] Professor Smith on Amorphous Sulphur. 
591 
destroyed the ability to give insoluble sulphur. Their use did not 
however, affect the viscosity above 160°. 
5. It was shown that air and sulphur dioxide restored the ability 
to give insoluble sulphur. The halogens, the halogen hydrides, 
and even dry phosphoric acid, had the same effect. 
6. It was found that sulphur which had been treated with 
ammonia while melted, and had afterwards been recrystallised, if 
used at once, froze at 119T7° and contained no insoluble sulphur. 
In a previous investigation ( Proc . B.S.E., vol. xxiv. p. 299) it had 
been shown that insoluble sulphur, when present, depressed the 
freezing point, in accordance with Raoult’s law. 
7. Sulphur containing iodine (100:2) gave when heated and 
chilled large amounts of insoluble sulphur. These ranged from 
4 per cent, at 110° to 62’7 per cent, at 448°. 
8. The amount of insoluble sulphur obtained at 150° was pro- 
portional to the quantity of iodine present when the quantity of 
the latter was 1 per cent, or more. 
9 Sulphur prepared by distilling the element and quenching 
the burning stream in ice-water gave 51 per cent, of insoluble 
sulphur. Chilling boiling sulphur in ether gave 44T per cent, of 
the insoluble form. 
10. It was demonstrated, by identity in boiling points under 
ordinary and reduced pressures, and by identity in specific gravities, 
that sulphur which will give the insoluble form when chilled is 
identical in constitution near the boiling point with that which 
will not. 
11. It was shown by identity in solubility between 120° and 
160° that the two kinds of sulphur mentioned in 10 are identical 
in constitution also below the transition point of S to S A (160°). 
12. The facts referred to in 10 and 11, together with the con- 
clusions of the preceding paper showing the identity of the two 
kinds of sulphur at the transition point (160°) itself, demonstrate 
that the insoluble form is present in all specimens of melted 
sulphur in proportions depending upon the temperature alone, 
whether, by treatment with ammonia or otherwise, they have lost 
the capacity to give insoluble sulphur by chilling or not. 
13. The conclusion is reached that amorphous sulphur is 
supercooled S/a, — the form stable above 160°. 
