272 Meteorological Observations at Hudson, Ohio. 
The temperature at 9 a. m. is 1:0° above the mean, from one 
year’s observations at Philadelphia; it is 0:19 above the mean, 
from two years’ observations at Toronto; 085° below the mean 
from two years’ observations at Montreal ; average 0:12° above the 
mean, from 5 years’ observations. This quantity is so small that 
I neglect it altogether. Subtracting 0-2° for the zero error of the 
thermometer, we have 48-9° for the mean temperature of Hudson. 
The temperature of the Atlantic coast in the same parallel is 
50:6°.—Difference, 1:7°—being at the rate of one degree for 642 
feet elevation. From observations made in the state of New 
York, Mr. Coffin has deduced a decrease of 1° for 372 feet eleva- 
tion. 
The observations on wells, commenced in my former article, 
have been continued to the present time. 
A i B 
Date. Depth. jEpEratia ___ Depth. Temperature. 
1841, August 3, 54:5 feet. 50-99 A8 feet. |, 50°39 
1842, February 25, | 55 50:2 AT 48:0 
August 22, 54 51:3 A6‘5 50°4 
1843, April 5, 55 50:1 A6 47‘8 
August 26, 5A 51:3 A5:5 50:0 
1844, March 21, 53°5 50:0 A5 AT ‘5 
August 27, 53:0 50°8 AA A9‘7 
Mean of three years, | 54°3 506 | 463 | A491 
Mean of six years, 5A‘1 50:5 466 49:0 
The annual range of temperature of A, is 0:9°; of B, 2°3°. 
If we could assume that the temperature of a well was simply 
that of the stratum in which its springs take their origin, we 
could compute the depth of the springs from the annual variation 
of temperature. From these data, we should find that the well 
A was fed by springs at the depth of 42 feet, and the well B at 
the depth of 30 feet. In fact, however, it is plain that the change 
of temperature of these wells is not due to conduction, in the 
usual mode in which heat travels along a metallic bar, a solid 
rock, or dry earth, for then the maximum temperature could not 
occur before mid-winter ; whereas, according to my former article, 
(p. 316,) the maximum occurs in August or September, and the 
minimum in January or February. It seems clear, then, that 
this heat must be conveyed downward by the small streams of 
water which filter through the soil, and are occasionally found in 
considerable veins. These streams start with the temperature of 
