1904-5.] Prof. Smith on Two Liquid States of Sulphur. 589 
so sharply as does recrystallised sulphur, and seems to be subject 
to superheating. 
4. It was shown in a previous paper ( Proc . Roy. Soc. Edin ., 
vol. xxiv. p. 342) that ordinary sulphur owes to the presence of 
sulphur dioxide its tendency to give amorphous sulphur when 
chilled, and that sulphur which while melted has been treated 
with, ammonia, gives when quenched nothing but soluble crystal- 
line sulphur. The phenomena described in 1 and 2 above take 
place in the same way and at precisely the same temperatures, 
whether the sulphur concerned is such as by chilling gives in- 
soluble sulphur, or, having been treated with ammonia, does not. 
5. The existence of two independent curves of solubility for 
the two kinds of liquid sulphur in triphenylmethane and other 
solvents is demonstrated. The solubility of yellow mobile 
sulphur (S A ) increases, that of brown viscous sulphur (S M ) de- 
creases, with rise in temperature. 
6. The expansion of yellow mobile sulphur (Sa) diminishes 
rapidly from 154° to 160°; that of brown viscous sulphur (S^) 
increases rapidly from 160° upwards. The statement under 4 
holds in this case also. 
7. The dilatometric method gives no evidence of the existence 
of Frankenheim’s transition point (250-260°). 
8. It is shown that the point of minimum dilatation is displaced 
upwards when triphenylmethane is dissolved in the sulphur. The 
displacement averages 2*8° for 1 per cent, of this foreign body. 
9. The production of the new phase is easily to be seen when 
strongly heated brown viscous sulphur is allowed to cool in a test- 
tube. The radiation from the greater surface at the bottom 
causes the formation of the mobile yellow liquid first in that 
region. The interface between the two varieties is quite distinct, 
and recedes slowly up the tube as the transition proceeds. Owing, 
however, to the progress of the change within the upper brown 
layer, the interface gradually becomes indistinct. 
10. It is thus shown conclusively that there are two liquid 
states of sulphur, which are partially, but only partially, miscible. 
These are S A , which predominates from the melting point to 1 60°, 
and S^, which prevails above 160°. As the temperature ascends, 
saturation of the former with the latter determines the separation 
of the new phase, and conversely when the temperature falls. 
( Issued separately April 18, 1905.) 
