82 DR GEORGE WILSON ON THE FINITE DIVISIBILITY OF MATTER. 
regions of the atmosphere, may be such at its boundary as to destroy the elasticity 
of the air, and even to liquefy or solidify it.* DAvuBENny,+ Kane,{ and others, 
have replied to this, that the temperature of planetary space, according to FourtEr, 
ScHWANBERG, and others, is much higher than that to which air has been exposed 
in experiments with solid carbonic acid and ether, without destroying its 
elasticity. Dumas, in anticipation of such objections, has declared, that we are 
not to consider the temperature which a thermometer would exhibit if placed in 
the upper strata of the atmosphere, as necessarily identical with that of the air 
around it.§ By which statement he means to enforce, if I understand him aright, 
that non-elastic (liquid or solid ?) air may, like other diathermanous bodies, trans- 
mit heat without being thereby raised in temperature itself, so that the outer 
shell of air may be colder than the layers within it, or space beyond it. In allu- 
sion to such a view, Professor JAmEes Forzes has pointed out the difficulty of un- 
derstanding “ how it is possible that the higher strata of the atmosphere can 
remain permanently colder than the strata beneath and the sky above them, 
without admitting a paradox of the same kind with a mechanical perpetual 
motion.’ || 
In reference to Dumas’ mode of disposing of WoLLAsTon’s argument, I would 
only further observe, that natural philosophers are not at one as to the tempera- 
ture, either of planetary space or of the upper strata of the atmosphere; so that 
it is impossible at present to say what is the exact value of the objection I have 
been discussing. 
4th, Finally, several physicists have denied the justness of WoLLAsTon’s con- 
clusion, on the ground of its intrinsic invalidity. Among these are Professor JAMES 
Forses{ and Dr Kanr,** who have not, however, so far as I am aware, stated 
in what way they dispose of the argument. Professor WHEWELL is likewise an 
objector, and dissents from Wot.aston’s inference, on the plea that the latter was 
not at liberty to assume that the law which connects the density of the air with 
the compressing force at the upper boundary of the atmosphere, is identical with 
that which is known to prevail near the earth. His own words are—“< We know 
nothing of the law which connects the density with the compressing force in air 
so extremely rare, as we must suppose it to be near the boundary of the atmo- 
sphere. Now there are possible laws of dependence of the density upon the com- 
* Lecons, &ce., p. 239. 
} Supplement to the Introduction to the Atomic Theory, p. 11. 
¢ Elements of Chemistry, p. 441. 
§ Legons, &c., p. 241. 
|| Report of British Association, 1841, p. 79. 
Op. cit p- a 77% 
** Elements of Chemistry, pp. 15 and 358. 
