Meteorological Observations at Hudson, Ohio. 273 
the surface, but are gradually robbed of it by the strata through 
which they pass. The range of temperature, then, at a given 
depth, will depend not merely upon the depth, but upon the time 
occupied by the water in its descent. 
. But the most perplexing anomaly is the constant difference, 
1:5°, in the mean temperature of the two wells. It cannot be as- 
cribed to difference of depth, for this is only 7-5 feet, and indeed 
the level of the water in A is about 7 feet higher than that in B. 
Can it be ascribed to the different depths of their springs? An 
increase of temperature of 1:5°, corresponds to a depth of about 
60 feet. Admit that the springs of A come from a depth 60 feet 
greater thah those of B; much of their heat would be lost in tra- 
versing this distance, so that the difference in the temperature of 
the wells would be less than 1:5. Moreover, the observed range 
of temperature and time of maximum indicate a free communi- 
cation with the surface of the earth, which is inconsistent with 
' the supposition of its being entirely controlled by springs at a 
depth of sixty feet, where the annual variation of temperature is 
well nigh extinct. I infer, then, that this well must have a 
pretty free communication with springs at a depth of perhaps 
- 200 or 300 feet, where the mean temperature is several degrees 
above that of the surface; while by means of descending streams 
- there is a communication with the surface sufficiently free to 
cause an annual variation of temperature above what is due to the 
depth of the well. This, then, is a veritable hot-spring, as much 
as the hot-springs of Virginia, and its high temperature is to be 
ascribed to the same cause 
The following table ashibets all the days in which the Sie 
mometer has fallen to zero 
18%3, February 8, 4 z M. as ae -  —05° 
“16, 63 A.M - = 17° 
“6 3 17, 6 A. M. —7‘8° 
In the winters of 1841-2, 1843-4, lk 1844-5, that is, three 
Winters out of seven, the thermometer was not observed in any 
instance to sink to zero 
The following tible eahigie all the days in which the ther- 
mometer has risen to 
1841, June 8, - - “90° 1843, July 1,. - 91-39 
« July.23, - - 93 " ‘’ 17, - 92:4 
HM Bhs ow 29 90 6 # 23,4 $k 
« Aug. 18, - - 905 
