162 



Readings of River Gage at Havana, i{ 

 (Plane of reference, low water of 1873.) 



These gage-readings at Havana have been plotted in the 

 hydrographs of Plates VIII. to XIII. on a scale large enough to 

 show the minor fluctuations, and at the same time to serve as a 

 basis for the graphic representation of temperatures of the 

 water and the results of the quantitative study of the plank- 

 ton. The hydrographs for 1894 and 1895 are based upon the 

 records at Copperas Creek with such supplementary data as 

 our incomplete records at Havana provide. For cohvenience in 

 comparing the seasons in the several years the following tables 

 have been prepared from the same data, to show the monthly 

 and yearly means, extremes, range, and total movement. 



