of the Lower Strata of the Atmosphere. 45 
peared momentarily a little warmer than the stratum situated 
at the height of 5 feet, even when, from the latter elevation, 
the increase of temperature upwards was already established. 
Thus, on the 3d October, at half-past five o’clock, the weather 
being clear, and a few moments before sunset, a thermometer 
at the surface of the ground indicated 13°.3, and another at 
the height of five feet only 13°, while the atmosphere at an 
elevation of 80 feet, was at a temperature of 14°.55. The same 
thing was observed on the 5th August at seven o’clock in the 
evening, the weather being slightly cloudy, after a rainy after- 
noon, when I found the temperature of the turf at 17°, while 
that of the stratum of air 5 feet above it was only at 16°. 
This temperature, however, continued gradually to increase to 
the height of 105 feet, where it stood at 17°.1. My observa- 
tions, from the 6th to the 8th September, presented the same 
results. In exceptional cases of this nature, it is not easy to 
explain the sinking of the temperature in the strata of air 
nearest the earth relatively to that of the higher strata. The 
theory of radiation, indeed, ascribes it to the cooling of the 
ground, as a consequence of nocturnal radiation, which com- 
municates itself to the nearest strata of air, then in succession 
to the superior ones, with a decreasing intensity as we ascend. 
But if the ground itself is found to be warmer than the body 
of air surrounding it, the above explanation becomes inadmis- 
sible, at least without some modification. Perhaps the ano- 
maly in question, which, moreover, very rarely presents itself, 
may be owing to a precipitation of dew,so sudden and abundant, 
as momentarily to warm the surface of the ground ; the latter, 
after a short time, would again cool by nocturnal radiation, and 
before the slight elevation of temperature it had acquired 
could communicate itself to the nearest strata of the atmos- 
phere.* 
I formerly mentioned, that one of the objects I had in view 
by repeating Pictet and Six’s experiments, was to study the 
relations which must exist between the indications of Leslie’s 
Si be a en nee 2 ee ee 
%* In the course of upwards of a year’s observation, I observed the above 
anomaly only four times, and always a little after sunset, the time when the 
deposition of dew is most abundant. 
