IN THE MONTH OF FEBRUARY, 1842. él 
ter at no time rose 7° above the mean. According to the reports of the British Associa- 
tion for 1839, page 15, on the Ghats of Western India, there fell, in 1834, 302 inches of 
rain, (= 25 feet,) of which 118 fell in July, while the mean variation of temperature for 
the month was only three degrees! These extraordinary rains seem rather to cool than 
heat the atmosphere at the surface. 
3. The reason of this last remark will appear from observations of the temperature of 
the fallen water. According to observations at Cuba, published in Silliman’s Journal, 
Volume xxxi., page 289, the mean temperature of falling rain water, was more than 
eight degrees below the mean temperature of the locality. ‘T’he reason is obvious. The 
precipitation takes place ata great elevation, and the water descends with the tem pera- 
ture of that region. ‘This cold shower, mingling with the air at the surface, lowers its 
temperature, or prevents that elevation of temperature which might be expected from the 
heat liberated in the condensation of the vapour. I do not see, then, how we can ascribe 
any considerable part of the effect in question to the heat of the condensed vapour. Can 
it, then, be ascribed wholly to a change of latitude of the wind? On the Atlantic coast, in 
winter, the change of temperature is 15° for 10° of latitude. In the interior the change 
of temperature is greater. ‘Thus, 
‘Temperature of Fort Churchill, latitude 58° 57’ north, in winter is 20°23. 
ns % Hudson, “ Ai ie “ 27 .68 
17° 42’ 47°,91 
Or 27°.1 for ten degrees of latitude. 
Temperature of Fort Snelling, latitude 44° 53’ north, in winter is 16°.70. 
“ Natchez, ..“... 8b. H..“ ne 50 .82 
13° 19’ 33°.62 
Or 25°.2 for ten degrees of latitude. 
Over how many degrees of latitude did the wind in question blow? On the morning 
of February 17, 1842, the thermometer, in Maine, stood 20° above the mean. Allowing 
five degrees for radiation, we have an effect of 15° to be accounted for. The wind had 
been blowing from the southward about twenty-four hours, with an average velocity of 
about forty miles per hour, equal to nine hundred and sixty miles, which probably cor- 
responds to six hundred and seventy-nine miles in the direction of a meridian, or nearly 
ten degrees of latitude. ‘This wind might, consequently, have come from Bermuda. 
The temperature of Bermuda, latitude 32° 34’ in winter is 59°.11. 
& 66 Eastport, 66 A4 54 6c 66 a) 42 
Effect of latitude, . ©. + + 12°20! 36°.69 
Or 29°.7 for ten degrees of latitude. 'This air, then, should have an excess of heat 
much greater than that actually observed, provided that none was lost in the transfer. 
We may allow a loss of one half, and still have an excess sufficient to satisfy the obser- 
vations. 
December 21, 1836, the temperature in New England was also 20° above the mean. 
