12 



FLUCTUATIONS OF LEVEL 



TABLE OF WATER LEVELS 



All tlie nieasureraeiits reduced to the zero, or line of reference, at 



The diagram of monthly variations for Lake Ontario (see Plate I, No. 2) is 

 constructed from the register of H. T. Spencer, Esq., made once a montli at tlie 

 mouth of the Genesee river. A single reading for each month may fail to give 

 a good average, but the regularity of the figures show that care was taken to avoid 

 rough weather. 



The table for Rochester is copied from the annual reports of the regents of the 

 university. For a transcript of the registers at Oswego, I am indebted to M. P. 

 Hatch, Esq., tlic liarbor agent at tliat place. This includes a greater number of 

 years, but except for the last two tliey are incomplete. 



