Leslie on Meteorology. 177 
much stress upon it, if we recollect the progressive diminution 
of temperature which takes place in the higher regions of the 
atmosphere, whence its density will be greater than the mere 
logarithmic formula indicates. ) 
Mr. Leslie’s next speculation is far more visionary than the 
above (which is by no means new), and seems strangely mis- 
placed in a Dictionary of the Sciences. 
Having ventured to state that the highest region of the atmosphere is 
probably occupied by some very diffuse phosphorescent gas, we shall 
hazard a conjecture which will appear bolder, and even paradoxical ; 
that perhaps air, in its most concentrated state occupies the bottom of 
the ocean, and forms a vast bed, over which the incumbent waters roll. 
Air has actually been condensed above a hundred times, and during this 
process it betrayed no deviation from the fundamental law, that its elas- 
ticity is directly proportional to its density. There seems no reason, 
therefore, to doubt, that if an adequate compressive force could be exerted, 
air might be reduced to the thousandth part of its original volume, But 
this elastic fluid would then be denser than the water, and consequently 
instead of rising, would fall through the liquid. Suppuse, for instance, a 
bladder filled with air, and having a small bullet attached to it, were 
thrown into the sea; in continuing to sink, it would reach a depth where 
the enormous weight of the column of water would compress it to the 
same density as the surrounding mass; and if the bullet were now disen- 
gaged, the bladder would remain suspended in that stratum, or if carried 
a little lower, it would precipitate itself to tle bottom. 
He then enters into a tedious calculation to show that 
at the depth of 28.885 feet, there would be an equilibrium 
between the condensed air, and the corresponding stra- 
tum of sea water. This computation (adds he) is to be considered 
as only a near approximation, yet sufficiently accurate for the object in 
view. Nor shall we fatigue our readers by the investigation of a strict 
formula, including exponentials. It is enongh to mark the conclusion, that 
any portion of air carried five and a half miles below the surface of the sea 
will never ascend again. Now this limit is only half the depth, which, the 
theory of tides assigns to the waters of the ocean. Thereis more difficulty 
in conceiving by what process air can be conveyed to its abyss. Increase 
of pressure, however, enables water to hold a larger share of air; and the 
effect is hence the same as an angmented attraction. ‘The minute globules 
of air, may therefore be gradually drawn downwards from stratum to 
stratum, till they are at last detached from the body of water by their own 
superior density. The precipitation and accumulation of concentrated air 
under the ocean, would thus be the result of some unceasing operation, 
Such a process may, perhaps, constitute a partof the great economy of Na- 
ture. It seems probable, that the existence of a subaqueous bed of air is 
necessary to feed the numerous fires which occasionally rage in the bowels 
of the earth, and occasionally burst forth on the surface in volcanic spi- 
racles*. 
We think this the wildest conceit that has ever figured ina 
sober work on philosophy. It throws Bishop Wilkins’ schemes 
quite into the shade; and seems to rival some of Mr. Southey’s 
oriental fictions, from one of which, the Domdaniel cavern, it is 
manifestly borrowed. We shall not consume ourreader’s time with 
* P. 326. 
