. Imcrican Fisheries .Voi/r/j. 99 



State \vc feel safe in sayiiiii" thai ( )lii() (It)elli all iliinj^s well, and 

 that this exposition, at Toledo, in U)Oi,, will be an ( )hi() exposi- 

 tii>n in every sense of the word. 



Mr. Clark: 1 think that we had belter take a recess at this 

 time, as it will crowd us considerably to attempt to close our 

 business this afternoon. There is one paper especially that 1 am 

 very much interested in that is yet to be read. Dr. lienshall's 

 paper. 



On motion, the Society took a recess to 2 (^clock p. m. 



AFTERNOON SESSION. 



Two p. m. — The meeting was called to order by President 

 May, and Professor IWrge read a paper entitled : 



THE RELATION BETWEEN THE AREAS OF INLAND LAKES 

 AND THE TEMPERATURE OF THE WATER. 



Air. President and Gentlemen: 1 am going to speak this after- 

 noon on the subject of the temperature of the small inland lakes, 

 especially as affected by the area of the lake, i-'or the last two 

 or three years 1 have been working on the biological condition 

 of the inland lake, taking up one point at a time, as my leisure 

 from the University work will allow me to do it; for the past 

 season I have been working on the temperature. The main work 

 1 have been doing is on my ow'n lake Mendota, immediately ad- 

 joining our University. During the last open season I had tem- 

 peratures taken of the water at all depths, twice a day during the 

 season, and during the present season from the first of May on. I 

 have been continuing the taking of the temperatures in that same 

 fashion, and I expect to coiUinue the work to the end of the sea- 

 son, hoping thus to get a tolerably complete idea of the changes 

 of the temperature of the lake. In connection with this work I 

 have been carrying on, especially this season, observations of 

 some of the smaller lakes, at C^conomowoc, about sixty miles 

 from Madison. The special point of these observations has been 

 to see what the effect of the area of the lake would be on the depth 

 to which .the heat of the sun penetrates into the water. 



The temperature of the water is one of the most im[)ni-tant 

 biological conditions in an inland lake. The temperature of the 

 surface starts in spring from t,2 degrees, and rises in summer to 

 the very considerable height of 70 or 80 degrees, and falls again at 

 the close of the warm season to the freezing point. This great 

 gain of heat during the sununer is caused, of course, bv the action 



