TRANSACTIONS OF THE SECTIONS. 89 
the application of the results of observations on bodies in the spheroidal state ta 
the physical constitution of the globe. He assumes that our globe at the present 
time consists essentially of three distinct portions :— 
Ist. A central nucleus in a state of igneous fusion. 
2nd. A crust at a comparatively low temperature, the inner side of which is in the 
spheroidal state. 
3rd, A space between the crust and central nucleus, possibly filled with vaporized 
mineral matter. 
The arrangement of these several portions, and their connexion one with another, 
may be better understood by reference to the constitution of an egg, which bears a 
streng analogy to it, in point of arrangement, though differing in shape. The yolk 
of the egg represents the mass of matter in a state of igneous fusion ; the white of 
the egg the space between the heated mass and the crust ; and the shell of the egg the 
crust of the globe. When referring to the experiment with the platinum rod, he 
Stated, when it was heated to the required temperature and plunged into water, 
that the liquid did not touch the rod, it was seemingly repelled by it, and that there- 
fore a space intervened between the rod and the water. In the proposed theory, no 
difference is made in point of arrangement, merely the substitution of one kind of 
matter for another. In the experiment, there is the heated rod, the space and the 
water in the spheroidal state; in the theory of the globe, there is the hot sphere, the 
‘space and the matter, the inner surface of which is in the sphercidal state. The 
crust of the globe under these conditions is influenced by two great forces, viz. gravi- 
tation and spheroidal repulsion, the former tending to draw the crust towards 
the central nucleus, the latter repelling it from it. The crust will therefore have 
assumed the position where the equilibrium of the two forces is established. 
To account for a fluid internal nucleus at a higher temperature than the solid crust 
of the earth, the author applies that remarkable property which bodies in the sphe- 
roidal state present, of total reflexion of the heat incident upon them. The effect 
of this property must be to make the inner surface of the crust of the globe (which 
it will be remembered is in the spheroidal state) equivalent in every direction to an 
immense concave mirror, whose temperature will be very slightly affected by the heat 
which falls upon it. Such a condition of matters is manifestly compatible with the 
presence of a much higher temperature at the central nucleus than at the inner sur- 
face of the crust, and necessitates a much lower cooling of that crust, and conse- 
quently of the nucleus which it robs of heat, than would be the case if the power to 
reflect heat were not characteristic of the spheroidal condition of matter. 
The author then draws attention to the applicability of this hypothesis to explain 
the density of the earth (5°67 according to Baily), which should have been much 
greater than it is were the globe wholly a mass of liquid and solid matter. When the 
space between the liquid and solid portions is taken into consideration, there is 
ample room afforded, by which the density of the globe, as a whole, might be more 
or less lowered. ; 
In applying the observations upon matter placed in the spheroidal state to explain 
volcanic phzenomena, it is assumed that there exists, contiguous to the volcanoes of 
our globe (either formed, or in the act of formation), basin-shaped cavities, more or 
less deeply seated, the under part of which is composed of metallic bodies at a 
high temperature. Water, either from lakes, &c., at the surface or from subterranean 
reservoirs, finds access to one of these cavities. The first portion which descends 
instantly assumes the sphercidal condition; more water enters, and still it is sphe- 
roidized ; the stream continues, till in course of time an immense volume of water 
is there rolling about, but not yet touching the metallic surface ; ultimately, however, 
the balance is overturned; the liquid, by robbing the metal of a sufficiency of heat, is 
enabled to touch the metallic basin; an immense volume of water is thereby instantly 
converted into steam, while at the same moment chemical action on a large scale 
speedily ensues between the liquid and metallic bodies, the latter action giving rise 
to heat quite sufficient to fuse large portions of mineral matter. The almost instar= . 
taneous generation of large volumes of vapours and gases, and these promptly aug- 
mented in bulk for some time, would soon produce a force quite able to raise large 
tracts of land; and when a vent was made or obtained, would eject the fused mass, 
-as seen to happen from our volcanoes. 
