C. M. Wetherill on crystallization of Sulphur. 339 
_ Regnault found the specific heat of (« S) = 0-20259, and 
Marchand and Scheerer that of (¢S) = 0:20684. During the 
passage of (7 S) to (« S), a considerable amount of heat is evolved. 
- Hence in the red amorphous variety, the molecules are more 
widely separated, and are in acondition of unstable equilibrium. 
In satisfying their tendency to approach each other, they assume 
(by the fusion method) the beta form of prisms of the monoclinie 
system ; but they soon pass into the condition of rest as rhombic 
octohedra (« S), of the trimetric system. This transformation 
takes place, as is well known in the solid prism, which is, without 
change of form, converted into numerous smaller crystals of (a 8). 
According to Frankenheim, “gamma” sulphur, like other so- 
called amorphous bodies, possesses the property of crystalliza- 
ion; but the manifestation of the phenomenon is prevented by 
the admixture of alpha and beta sulphur. Heat is the agent by 
Which the («) form is converted into the (?) and (y) modifications, 
and has always been supposed to play an important part in the 
erystallization of this element. The ordinary or alpha sulphur, 
when crystallized from its solvents, sulphid o carbon, or oil o 
turpentine, reappears as octohedral alpha sulphur. 
_Frankenheim, however, observed that when the body is pre- 
Cipitated from its solutions atat t g its point 
Gigi : re 
of fusion, it assumes the prismatic form of beta sulphur 
solution, either in @ or 6 crystals, acc 
the molecules of sulphur are separated, and 
Positions required for (@S); while, during th 
: oe : 
dral form, in which they are in stable equilibrium. 
_ Each of the allotropic conditions has pr 
voy Nageed density and its own chemical 
_ Ihe only known vapor densi 
having been determined from their transformati 
