40 Recent Chemical Researches . [January* 
tension of the phosphorus vapour. It is found that for a 
given temperature there is a certain fixed tension of the 
vapour required to hinder the transformation of ordinary 
into amorphous phosphorus. As the temperature increases* 
however, the transformation is again set going, until the 
tension of the vapour increases to such an extent as again 
to stop the adtion. If phosphorus be heated in a confined 
space, different parts of which are maintained at different 
temperatures, the tension of the vapour will prevent the 
formation of the amorphous variety, except at the hottest 
parts of the space. May we imagine that some such state 
of affairs prevails in the atmosphere of the sun and of 
the hot stars ? — that the atomic alteration, shadowed forth 
by Mr. Lockyer’s researches, which appears to take place in 
non-metallic molecules, consists not in the decomposition of 
these molecules with the production of simpler forms of 
matter, but in the production of isomeric or allotropic forms 
of them with which we, on the Earth, are as yet unacquainted ? 
■ — that at ordinary temperatures the tension of the vapours 
of the elements is sufficient to stop this action, but that at the 
high temperature of the sun’s atmosphere the transforma- 
tion takes place ? — and that, as these allotropic forms 
ascend to cooler parts of the sun’s atmosphere, the tension 
of their vapour is able to bring about the re-formation of 
those molecules which are known to us on the earth ? 
That quantities of energy are absorbed or evolved in the 
passage of one allotropic form of an element to another is 
evident from the results of experiments made by Mitscher- 
lich and others upon the forms of sulphur. The conversion 
of i grm. of dissolved octahedral sulphur into insoluble 
amorphous sulphur is attended with the evolution of 12,800 
heat-units. A careful study of the loss or gain of energy, 
in the reciprocal formation of allotropic varieties of the 
non-metallic elements, would doubtless lead to most im- 
portant results. 
Weber has found that the specific heats of the various 
allotropic forms of carbon differ at low temperatures, but 
that at those temperatures at which the optical differences 
begin to disappear the differences in specific heats disappear 
also. At high temperatures carbon has but one specific 
heat ; hence it exists apparently in but one form. 
The faCts about allotropic modifications of elementary 
bodies may possibly have an influence upon the constitution 
of compounds. Weber concludes from researches, a full 
account of which has not yet been published, that the spe- 
cific heat of carbon in combination varies according to the 
