Central Heat of the Earth, and Volcanic Phenomena. 129 



work counteracting the enormous pressure of the superin- 

 cumbent mass, or that a space or spaces should be satisfac- 

 torily accounted for. The theory under discussion admits of 

 neither of these alternatives. The liquid cannot be raised in 

 temperature without the crust becoming fused, and as for a 

 space filled with vapour, this theory does not admit of one. 



From the foregoing remarks it may be deduced, that while 

 it has been satisfactorily demonstrated, that a rapid increase 

 in temperature towards the centre of the globe does take 

 place, which would lead us to believe that the greater por- 

 tion of this globe is in a state of fluidity, nevertheless the 

 two theories which have been discussed, though they take 

 cognizance of, and account for this increase in temperature, 

 yet cannot be accepted, as they severally assume what appears 

 clearly impossible. 



My object in the following remarks is to shew that the 

 apparently incompatible phenomena of a solid crust at a low 

 temperature, enveloping a liquid at a higher one, may be 

 realized. 



The view which I am about to propose is founded upon 

 the assumption by matter when raised in temperature of the 

 peculiar state distinguished as the spheroidal ; and it will 

 conduce to perspicuity, if I commence with a brief reference 

 to the recent researches on this subject. 



For the greater part of the knowledge we possess, regard- 

 ing the phenomena presented by bodies when they assume 

 the spheroidal state, we are indebted to the laborious investi- 

 gations of M. Boutigny. The chief points of interest in rela- 

 tion to the present inquiry observed by him are the follow- 

 ing,— water being selected as the example of the body 

 exhibiting, when heated, the spheroidal state. 



Few phenomena are more familiar than that of water, 

 when placed at ordinary temperatures in a metallic or other 

 vessel, wetting its surface and spreading over it, and we are 

 equally familiar with the effect of elevation of temperature 

 in such circumstances, in dissipating the water in vapour. 

 If, however, instead of raising the temperature of the vessel, 

 after the addition of the water, the vessel be first raised to a 

 temperature of not less than 340° Fahrenheit, and some water 



VOL. L. NO. XCIX. — JANUARY 1851. I 



