40 TRANSACTIOXS OF THE CANADIAN INSTITUTE. [VoL. Y. 



The observations as to the level of the water in Lake Ontario were 

 commenced by the directions of Capt. Richardson, Harbour Master, in 

 1854, though a regular float gauge was not constructed until 1856, and 

 since that time the gauge has been four times shifted, care having been 

 taken to preserve the datum. I can personally vouch for the correctness 

 of the observations, having occasion to refer to them constantly as Har- 

 bour Engineer since 1853, a period of over forty years. 



In the paper which I read at the Institute in 1879, it was stated that 

 the average rain and melted snowfalls , for 25 years were 34.172 inches, 

 the highest being 48.490 inches in 1878, and the lowest 24.344 inches in 

 1874. The average rain and snowfalls for 15 years, from 1878 to 1893, 

 were 31.217 inches, the highest being 39.715 inches in 1893, and the 

 lowest was 24.838 inches in 1882. The extreme fluctuations of Lake 

 Ontario between the years 1855 and 1878 inclusive, were in 1870, when 

 the highest water was reached on the 6th of May, 47 inches,. and two 

 years afterwards the lowest water occurred on the 19th of March, 1872, 

 16^ inches, an extreme of S^ij^ inches. The extreme fluctuations 

 between the years 1878 and 1893 were in 1886, when the highest water 

 was reached on the loth of May, 46 inches, and in 1892, not quite six 

 years afterwards, the lowest water occurred on the 7th of March, 13^ 

 inches, an extreme of 59^ inches, nearly four inches less than the 

 extreme fluctuations for the previous 25 years. The mean average for 

 the 25 years was 18,20 inches, and for the 15 years, between 1878 and 

 1893, was 15.17 inches. The diminution of nearly three inches in the 

 rain and snowfalls, and more than three inches in the fluctuations of the 

 above periods, induced me to examine the average rain and snowfalls, as 

 recorded by the Meteorological Observatory, and I find that the above 

 observations have been substantiated, as follows : — 



In 1858 the average of 17 years was 36.940 inches. 

 1868 " 27 " 36.273 " 



1878 " 37 " 35-464 " 



1888 " 47 " 34.632 " 



1893 " 50 " 34.338 " 



Showing a gradual diminution of 2.602 inches in 50 years. 



The cause of this diminution is not far to seek. The reckless destruc- 

 tion of the forests in Ontario, also Michigan and Wisconsin in the 

 United States, by lumbering and consequent fires, in the area of the 

 water shed of the great lakes, without a partial or corresponding substi- 

 tution of trees by planting, is a sufficient explanation of the result, 

 apart from other probable causes. 



The Ontario Government took the initiative, some years since, in es- 



