LOCAL CLIMATOLOGY. 97 



those winds for Ithaca come from off the land, and have not been 

 cooled by the lake until after they have passed the town. 



WINTER. Ithaca. Geneva. 



December, 1st half 32.93 30.28 



2d " 27.98 26.G9 



Januar}^ 1st " 29.53 24.96 



2d " 27.17 25.40 



February, 1st " 24.13 23.48 



2d " 28.82 2G.03 



SUMSIER. 



June, 1st " 63.69 60.60 



2d '' 66.77 64.81 



July, 1st " 69.80 70.44 



2d " 71.47 71.14 



August, 1st " 68.90 71.58 



2d " 68.37 68.09 



ill us, while the influence is quite manifest in the winter, pro- 

 ducing a difference of 3.28 deg. in favor of Ithaca, their average 

 for the winter being 29.42 deg., ours 26.14 deg. 



In the summer the difference is slight, and is in their fiivor 

 until the last half of August. For the first half of September 

 their average is 62.88 deg., ours 63.34 deg; for the last half, 

 theirs 56.08 deg., ours 57.61 deg. 



During the whole of the summer their return current comes 

 from over a tract of land which is quite uneven in surface, and has a 

 mean or average temperature considerably lower than Ithaca itself. 

 During the first part of the summer, until al)out the middle of 

 August, our return current comes, not from the lake at all, but from 

 a point of compass too far west of south to have been influenced 

 by the lake. After the first of August we have a much larger 

 proportion of southeast winds, and then Ave begin to feel the influ- 

 ence of the lake ; and while this influence is in the direction of 

 cooling during the day, it is, in its effects, a retardation of the 

 process of cooling through the night ; and thus, as I presume, 

 while our average for the twenty-four hours is greater than theirs, 

 our days are cooler and the nights warmer than at Ithaca. 



A reference to the prevailing surface winds, as observed at 

 Geneva, will be interesting and instructive in this connection. 

 Reckoning three observations per day, and we have on the ave- 

 rage about fifteen observations per month with no perceptible 

 winds. The others for the year are distributed as follows : 



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