PROCEEDINGS OF THE CANADIAN INSTITUTE. 



55 



The Great Lakes as a Sensitive Barometer. By Napier Denison, Esg., 

 Toronto Observatory. [Illustrated.] 



(Read February 6th, 1897.) 



For many years fishermen and sailors upon our Great Lakes have noticed, with 

 intense interest and curiosity, the rapid rise and fall of the water, most marked at 

 the head of shallow lagoons, as at our Island, and have considered it to be an inex- 

 plicable phenomenon. While in the vicinity of Lake Huron last summer the writer's 

 attention was attracted by what appeared to be a regular ebb and flow, at rapid in- 

 tervals, at the mouths of rivers. At Kincardine, ,by means of a special float, a set of 

 readings were taken, and a variation of level of over three inches obtained, averaging 

 nine minutes (that is, eighteen minutes for a complete undulation); the float moving 

 up stream at the rate of a mile and one-half per hour. Upon returning to Toronto, 

 by permission of Mr. Stupart, Director of the Meteorological Service, a simple in- 



strument was devised for automatically recording upon paper these peculiar oscil- 

 lations, and was set up at the mouth of the Humber river. 



The following is a brief description of this instrument (Fig. i). It consists of a 

 recording cylinder 24 inches in circumference and six inches wide, placed horizontal- 



