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 than 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, aoe its high temperature is to be 
ascribed to the same cause. 
The following table exhibits all the days in which the ther- 
mometer has fallen to zero. 
aan February 8, 4 A. M. - - - —0°5° 
cnet 16,%Gg-Ag M. - - - —17° 
% re 17, (OFA. ME. - - - —7:8° 
In the winters of 1841-2, 1843-4, and 1844-5, that is, three 
winters out of seven, the thermometer was not observed in any 
instance to sink to zero. 
The following table exhibits all the days in which the ther- 
mometer has risen to 90°. 
1841, June 8, - - 90° 1843, July 1, - 91:39 
Fs Sully 23, - 1,493 és “ 17; oie 
tc be De | 3k SO c 28. bi NGA 
oh Aas: 18; <9) =. 990°S 
