i20 Meteorological Journal. 
7. The quantity of rain that falls annually at the present 
time, I do not know. Ina journal kept by Mr. Atwater, 
find the following facts. Innine years, from Jan. 1786 10 
Jan. 1795, the average number of inches that fell, in rain, was 
37, the average number of inches of snow, 534. 1775 
was remarkable for the great quantity of rain that fell, it be- 
ing 512 inches—of snow 52 inches. In 1796 only 21 inch- 
es of rain fell. : 
Smoky Atmosphere—From the 7th to the 10th of Octo- 
ber, 1825, the atmosphere was so smoky as almost to render 
the sun invisible at mid-day. It extended over all the New- 
England States, and south to Virginia. Many people, who had 
left their windows open on the night of the 7th, were awaken- 
ed by the strong smell of smoke, and got up, with the im- 
pression that their houses were on fire. It is generally sup- 
posed to have been caused by the fires that raged about that 
time in Maine. 
Similar smoky days in the autumn of 1820, were attribu- 
ted to extensive fires near the Mississippi. The state of the 
atmosphere was such, and also the temperature, as proves it 
to have been so light, that the smoke would fall to the earth, 
though I had no barometer to ascertain its exact weight. 
_ The only objection against its being smoke from these fires, - 
is the improbability that it would extend over so great an 
extent of territory. But this is no insuperable objection. 
From an observation of these facts, it has occurred to me, 
that what is usually denominated the ‘Indian summer,” 
may be attributed to the same cause; viz. smoke diffused 
through the lower regions of the atmosphere. ’ 
If the atmosphere is dry and light, smoke will be aceumu- 
lated, and fall near the earth’s surface. If the atmosphere 
holds in solution a great quantity of water, the carbonic acid 
and some other ingredients entering inte the composition of 
smoke, will be absorbed. If the quantity of water be small, 
a plete absorption will not take place, and consequently 
the smoke will continually accumulate. If, now, after the at- 
mosphere has been dry specific 
should suddenly be diminished, the smoke will fall and pro- 
duce an Indian summer.. This smoky weather usually occurs 
after the autumnal rains, when the temperature is mild 
air serene; when it would seem that the atmosphere is both 
dry and light. A series of hygrometrical and barometrical 
