144 Proceedings of the Royal Physical Society. 
spheroidal lining would cease when the pressure increased, in 
a manner similar to the stoppage of vapour or steam from 
water at 212°, when the atmospheric pressure is increased. 
The distance between the central nucleus and the crust of 
the globe will be determined by the temperature of the 
nucleus, as the higher the temperature of the heated centre, 
then the further off will it repel or keep off the crust. Dr 
Macadam was still of opinion, that the only satisfactory 
theory which accounted for the compatibility of a cold sur- 
face and a highly ignited central nucleus was based upon the 
spheroidal condition of matter. The same theory, applied 
to the Geysers of Iceland, accounted for the discharge of hot 
water from these intermittent hot springs. 
Dr Wright, in reply, stated that Dr Macadam was mis- 
taken in supposing that the plate on which Dr Wright per- 
formed his experiments was heated too highly ; and this he 
showed to be the case by turning off the gas from the appa- 
ratus, when the water floating on the plate instantly came 
in contact with the latter, and exploded. It was not true 
that bodies in the so-called spheroidal state totally reflected 
heat. So far from that, they invariably became heated ; and 
solids such as camphor floated on the plate until they became 
quickly entirely liquefied, and converted into vapour. It 
was also incorrect to say that the distance between the 
spheroid and the plate bore any relation to the heat of the 
plate. He found that after a certain distance had been 
attained^ a further increase of heat was not attended with 
any effect. He maintained that temperature had really no 
essential relation to the spheroid state ; that the whole 
phenomena depended entirely upon the adhesion of vapour 
to the surface of the spheroidal body, and could be shown 
in various liquids, such as solutions of soap, alcohol, albumen, 
essential oils, &c., perfectly well when they were in the 
cold state. 
