3895-96.1 RAINFALL AND LAKE LEVELS. 121 



RAINFALL AND LAKE LEVELS. 



By R. F. Stupart, Director of the Observatory, Toronto. 



' [^Read 22}id February, iSp6.] 



During the past few months the rainfall observations taken at Canadian 

 Meteorological stations up to the end of 1895 have been collected and 

 collated for the purpose of publication. It occurred to me to try and dis- 

 cover how a varying annual rainfall affected lake levels, and whether there 

 are any good grounds for belief that the levels are becoming perma- 

 nently lower either owing to a diminished rainfall or from other causes. 



Prior to 1872 there were but few rainfall stations in the Dominion. In 

 that year, however, when the Meteorological Service was inaugurated, 

 regular ob.servations were begun at many stations, and at some of them 

 a continuous record has been kept up to the present time, but at most 

 voluntary stations observations are more or less desultory. 



The lake level curves up to 1888 have been taken from Mr. Charles 

 Crossman's chart, and the curves for subsequent years filled in from 

 information supplied by Mr. E. S. Wheeler, Assistant U. S. Government 

 Engineer, of Sault Stc. Marie, and by the Harbour Master of Toronto. 



From my knowledge of the irregularities of rainfall distribution, I 

 conceived that for a comparison of lake levels and rainfall curves the 

 latter should be formed from means obtained from observations made at 

 as large a number of stations as possible, and have therefore used all 

 stations in the Lake Region, both American and Canadian, which go 

 back as far as 1 874. 



For the watershed of Lake Superior we have three stations. Port 

 Arthur, Duluth and Marquette ; for Michigan and Huron, Beatrice, 

 Orillia, Presqu' Isle, Point Clark, Goderich, Parry Sound, Southampton, 

 Gravenhurst, Barrie, Alpena, Grand Haven, Chicago, Milwaukee, PLscan- 

 aba, and Lansing. 



For Lake Erie, Woodstock, Port Stanley, Port Dover, Detroit, Cleve- 

 land, Toledo ; and for Lake Ontario, Toronto, Kingston, Buffalo, Roch- 

 ester and Osvvesfo. 



Taking the pentad means at 30 stations scattered over the lake region 

 we find very little ground for belief that the annual rainfall has 



