Temperature of Plne^ Beaver and Ohanchee Lakes. '273 



TEMPER ATUEE OF PINE, BE AVER AND OKANCHEE 

 LAKES, WAUKESHA COUNTY, WISCONSIN, AT 

 DIFFERENT DEPTHS, EXTENDING- FROM MAY TO 

 DECEMBER, 1879 ; ALSO PARTICULARS OF DEPTHS 

 OF PINE LAKE. 



By Elizabeth M. Giffoed and Geo. W. Peckham. 



Pine lake is two miles long, with an average width of three- 

 quarters of one mile. Its mean depth, perhaps, being greater 

 than that of any other lake in the county. The most interesting 

 fact resulting from the observations is the regular decrease of tem- 

 perature with increase of depth down to eighty-five feet. At this 

 depth, from May to November, the mercury was constant at 42"* 

 Fahrenheit. In the observations on the temperature of Oconomo- 

 woc lake by the late Dr. Lapham — Transactions, Yol. Ill, p. 81 — 

 he states, " that an attempt was made to find the temperature at 

 the bottom in deep water, and resulted in showing at some times 

 no differences, and at other times one or two degrees warmer or 

 cooler; though the deep water is popularly believed to be much 

 colder than that at the surface." It is probable that his observa- 

 tions were not made with a self-registering thermometer, and in 

 drawing up a common thermometer from any considerable depth, 

 it would take on the temperature near the surface. As a result 

 of a number of experiments we found this supposition to be cor- 

 rect. Our observations show a difference of 14° Fahrenheit, in 

 surface and bottom temperature, until the middle of October. 

 Prof. Nichols found that the temperature in Forest Pond, Cam- 

 bridge, Mass., was nearly uniform from top to bottom about the 

 first of November. AYe found a uniform temperature December 

 2d. Probably in a larger lake this condition would not be 

 reached before January, For valuable data on the temperature 

 of Massachusetts waters, see papers by Prof. W. R. Nichols, in 

 the Massachusetts State Board of Health Reports. 

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