CO. Dewey on the Level of Lake Ontario. 399 
the general conclusion involved in these two results. : 
3, In 1848 the level was the lowest in November; in 1850 in 
November, and in 1856 equally low in November and Decem- 
ber, from the less rains in the preceding months. 
4. In 1848 the highest was in J. anuary ; and in 1857 in Octo- 
ber; and in 1855 in N ovember, from preceding rains. 
- The lowest measured in these years was in February, 1857, 
and the highest in August, 1858, giving the range in the whole 
nod to be 56—2—=54 inches. [The maximum and minimum 
evel was at Toronto in the same two months of these two years, 
and the range was the same, 54 inches, For this fact I am in- 
debted to the intelligent and accurate observer at that port in 
Canada West, the Harbor Master. The range is found to be 
nearly the same in Lake Michigan.] These facts show that the 
“mmon statements, in the summer of 1858, of the lake being 
‘ome feet higher than before known or in many years, were ut- 
muy false. In 1858 the level was seven inches higher than in 1867. 
- ere is no periodical rise and fall of the lake discernible on 
the lable, and the variations in the level of the lake seem to be de- 
pendent on very regular and adequate causes of supply and drain. 
7. Observation shows that the direction and force of the winds 
make the variations not altogether simultaneous at the ports 
having positions differently affected by the winds. Still a series 
of observations must lead to closely approximate res 4 
* “He table contains only the slow monthly and annu 
changes of the level. I have not introduced other measures, 
made i some other parts of this lake, on account of the impos- 
Sibility of reducing them to the same zero, as there has been no 
Feudard, but different points have been assuméd by ot 
‘either have I noticed those sudden changes of the level, w eae 
ie water falls or rises several feet in a few moments; ay ¥ . 
ay ie Wave causes the water to rise or fall alternately 
x fifteen minutes apart till the water comes to the previous level. 
Some of these are teste to have been caused by violent winds 
it titlwind tempests. Probably this is the uniform cause, as 
-* fully adequate to the effect. . 
t, N. Y., March, 1859. 
