292 
ON CHEMISTRY. 
red : rain and clouds have frequently been concomitants of a very 
high state of the glass; and during'easterly winds, a total stated 
suffusion, without a gleam of sunshine, has been maintained for days 
—nay weeks,—with great elevation of the mercury. Fine, clear, 
hot weather, with vast evaporation, has not uncommonly been wit¬ 
nessed at periods when the glass has been low, and the wind at 
south west. 
I cannot pretend to elucidate causes so deeply involved in obscu¬ 
rity, and governed by inscrutable laws; but I may conjecture that 
all the phenomena, however opposed they may appear one to the 
other—tend to demonstrate that, vapors taken up from the land and 
waters into the atmosphere are, by the electrising principle of light, 
converted into atmospheric air. A vast atmosphere of steam, or 
watery vapor is, as we have seen, carried up into the atmosphere : 
millions of tons of water are daily, hourly, evaporated from the sur¬ 
faces of sea and land ! How are these employed—to what are they 
resolved ? Let us take a case in point, and by bringing the enquiry 
before us in a tangible form, endeavour to arrive at an idea, at least, 
of the fact, and it’s consequence. 
The present dry season cannot prove a delusion. At the moment 
I write, the Barometer stands at the medium of the altitude which it 
has this year attained. Subsequently to the abatement of the vast 
continuous wind and rains of December and January, it gradually 
rose to 30 inches, thence to 30 (the greatest elevation which l 
have observed in Berkshire,) and that on March 16th. From that 
period, it fell to 29 10 ^y but recovered its altitude in a great degree. 
During the present month it has fluctuated between 30. 16 and 30 
-its medium being rather above 30. 20. This atmospheric 
lOOths ° 1 
weight,_almost unexampled in steadiness and duration—has bent 
attended with brilliant sunshine and perfect drought. The wind has 
varied a few points from the east, has been piercing at times, but 
generally unattended with that usual unpleasant concomitants of 
spring, east, winds. 
The volume of water carried up into the aerial ocean must have 
been enormous, and yet the aridity, the perfect dryness of the air 
has been almost undeviating. What has become of the watery va¬ 
por, where is it accumulated, or to what region has it departed ? 
Drought prevails here and elsewhere, barometer elevation is main¬ 
tained, no rain of moment has fallen since the last week of January, 
the precipitation even of the dew has been extremely minute ! Oc¬ 
casional hoar-frosts have occurred; but the only marked feature of 
the last six or seven weeks has been premature, confirmed aridity* 
