CORRESPONDENCE. 
249. 
Every fact goes to prove that thermal intensity, whether it be a wave (a 
vibration) or a fluid, is not uniform. Light and heat cannot be uniformly 
distributed through space, for the causes that generate them are not uni- 
form in regard to intensity and distance. 
The outside limit of the thermal ocean in space must be almost infinitely 
attenuated, and there is no evidence that refrigeration proceeds in a uni- 
form ratio from the centre to the circumference of the material universe, 
nor is there any proof that our system revolves in a circle equidistant from 
the cosmic centre. There is therefore no evidence whatever that our path 
through space is isothermal. It has also been stated b}' the editor of the 
' Geologist,' that to say, that the present meteorological changes on our 
earth are insulficient to explain the glacial eras, is merely a dogmatic asser- 
tion. In reply I have only to say, that if it be a dogmatic assertion, it is 
founded on faith in the invariable certainty and sequence of natural law, 
Have we not the wonderful and hitherto unexplained fact, that the polar 
regions once enjoyed the climate of Italy? — that the Sequoia Langsdorji 
(a Californian plant), the walnut, the plane-tree, and the vine once flourished 
within the Arctic Circle? (Steenstrup and Beer.) Is it not an incontrover- 
tible fact that Mount Lebanon was once covered with ice and snow ? I 
think it will be universally admitted that these facts are incapable of ex- 
planation by any known laws of our present telluric meteorology, and also 
that our path through space is not isothermal, which latter supposition, 
supported as it is by physical facts, will fully explain all the phenomena of 
terrestrial glaciation. 
In reply to the question in the last number of the * Geologist,' " what 
is the presumed temperature of the old cosmical space through which our 
globe is so liypotheticaily supposed to have passed in the glacial age?" I 
have to say that the solution to this query can only be found in vital ther- 
mometry, — in the changes north and south of the isozoic zones. For it is 
quite clear that during the period the earth was passing through the cold 
regions of space the isozoic zones moved towards the equator; and that 
while it was passing through warmer regions of space, the isozoic zones 
descended nearer the poles. Therefore from the changes of the isozoic 
zones on the earth's surface, an approximate calculation might be made of 
the various cosmical temperatures through w hich our solar system passed 
during the glacial geological periods so clearly recorded on the earth's 
surface. 
[If heat only exist where matter is, it must be subject to the laws of matter, and as 
a physical force would be in direct correlation with the other physical forces ; and if heat 
be confined to matter, how can we speak of hot and cold recions of space, where by that 
very admission neither heat nor cold can be ? Again, if confined to matter, it will, as 
far as our earth is concerned, be confined to that matter with which our earth is in con- 
tact, i.e. the great sphere of ethereal matter surrounding the sun, which is warmed by 
his rays and lit by his light, put in motion by his attraction or repulsion. If the sun 
moves on with his surrounding worlds, these w ill all travel onwards together in the same 
ethereal material envelope ; and therefore, unless the supposed hot and cold regions of 
space have temperatures of much higher or much lower degrees than the general tempe- 
rature of the solar region, the effect would be imperceptible. In this event, must we 
not suppose a radiation inwards of heat from space towards the sun, and consequently, 
one would suspect, a stoppage of all radiation from the earth ? But heat is a form of 
motion, and motion seemingly necessitates the existence of matter. If so, therefore — if 
heat exist in space — all space without end must be material. Can heat or cold exist in 
void space ? There is no cause whatever, no physical actio u, that I know of, that should 
either produce or accumulate heat in space or produce heated masses of space. Chemical 
combinations and chemical decompositions of matter might produce spheres of heated 
material space, but we have no data yet for such an assumption. — Ed. Geol.] 
VOL. VI. 2 K 
