Scott: Lakes of Tippecanoe Basin 



7 



placed by making an equal number of oar strokes between them. 

 This is a very rapid method, and, when a man has been properly 

 trained, is remarkably accurate; certainly sufficiently so in a 

 small lake. The effort was not to row at a standard rate, but to 

 keep the rate constant on each line. This eliminated the effect 

 of head and tail breezes. These soundings were checked by 

 cross series and stadia methods, which indicate that the errors 

 are very slight when they occur at all. 



Absolute accuracy of location is not claimed for them, but 

 they exhibit the form of the basins and permit a very close 

 approximation of their volume to be calculated. The soundings 

 have been recorded on the maps and contours drawn to facilitate 

 reading the maps and making calculations based upon them. 

 The contours are merely interpretations of the soundings. A 

 larger number of soundings would probably necessitate slight 

 changes. 



The capacity of the lakes and their areas are shown in the 

 accompanying tables. The areas of the maps have been deter- 

 mined by means of a planimeter. The volume has been deter- 

 mined by measuriag the area within each contour line by means 

 of a planimeter and then regarding the solid between the planes 

 of adjacent contours as the frustrum of a cone. The usual formula 

 for the calculation of the volume of a frustrum was then applied. 

 Only those lakes whose maps we have made are included in the 

 table. 



The areas of these lakes vary from a minimum of 85,084 

 sq.M. in Sawmill lake to a maximum of 3,265,607 sq.M. in 

 Manitou. In Dan Kuhn lake the deepest point is 7.9 M., while 

 in Yellow Creek a depth of 22 M. is reached. Yellow Creek 

 has also the greatest average depth (10 M.), while in Dan Kuhn 

 the average depth is oaly 2.588 M. In volume they range from 

 9,787,024 cu.M. in Manitou to 284,716 cu.M. in Sawmill lake. 



Of the lakes in this basin that have been previously mapped. 

 Eagle has a maximum depth of 24.7 M. and Tippecanoe 37.5 M. 



Tempekature 



So far as temperature and all the phenomena depending upon 

 it are concerned, lakes in temperate latitudes are very much more 

 alike in winter than in summer. In the late summer their differ- 

 ences are at a maximum. If only a single series of observations 

 of temperature and related phenomena can be made on a lake, 

 these observations are more instructive if made in late or mid- 



