f acK vertical interspace represents one degree'TaTirenheit, and tlie -fractional parts of a degree are indicated as exactly as possible in the plotting of the curves. Each fifth 

 degree is represented by a slightly heavier line. The transverse interspaces inclosed by the heaviet lines represent periods of ten days each, as indicated by the dates on tlie 

 Jeffchand side of the plate. The lighter transverse lines, intermediate between' the heavier ones, ar& intended to represent die mean of each ten days, and the curves of temper- 

 aturcareplottea-withreference to these lines. Theleft-hand vertical division Is devoted to fhe air. temperatures for .i88ij iSSi and 1883, die middle division to tlie surface 

 water temperatures for the same \ears, ihus permitting of a comparison ofi me two; and the righthand divisioa to tiie -water temperatures for 1884 and i88g 



