96 TWENTIETH ANNUAL REPORT ON THE STATE CABINET. 



From this it appears that the average is in our favor by some 

 three or four degrees in the coldest half month (1st Feb., 3.77*^) 

 in that part of the winter when their lake is shut out by frost and 

 otherwise from any influence on their climate, and ours is open and 

 with ice constant!}^ forming on its banks. 



In June, however, their climate is warmer than ours, 4.04 deg. 

 first half, and 2.13 deo'. last half, while our lake has not attained 

 its midsummer heat — for being very deep, it cools slowly ; but in 

 July and August, after the lake has become heated, and so pre- 

 vents the cooling of the air during the nights, &c., our tempera- 

 ture is the highest, 0.96 the first half of *July, 1.69 for the second 

 half, 2.83 for the first half of August, and 3.75 for last half. 



I think that nothing more can be needed to confirm the theory 

 I have advanced, of the influence of our lake on our climate. 



I will, however, introduce a-^other comparison ; that between 

 Ithaca, at the head of Cayuga lake. The physical position of the 

 two places is as follows : 



Lat. Long. Height above sea. 



Ithaca 42.27 76.30 417 



Geneva 42.53 77.2 567 



Ithaca has the advantage of about half a degree of latitude and 

 fifty feet of elevation, which, combined, make scarcely so much as 

 one degree of temperature in its favor ; but it is situated at the 

 south end of the lake, whereas Geneva is at the north end. The 

 lakes are much the same in size ; about forty-five miles long, with 

 an average width of two or three miles. Cayuga lake, however, 

 is much the shallowest, and freezes over more extensively than 

 the Seneca. 



The point of contrast, however, is chiefly this : the one is at 

 the south end, and the other at the north end of a long and nar- 

 row valley filled with a body of standing water. Now, from what 

 has been said, we should expect that the place at the south end 

 would receive much more of the warming effects of the lake in 

 winter, and less of the cooling effects in summer, for the reason 

 that in winter, while the water is warmer than the air, and is also 

 giving out heat by the formation of ice, the winds are prevailingly 

 the polar winds from the north ; consequently they are warmed 

 by the lake before they reach the town ; — while the winds from 

 the pole (the cold winds) pass over land, and from the land to the 

 water, to convey the heat away from us. But in the summer, 

 when the prevaling winds are the return current from the equator, 



