Each vertical Interspace represents one degree Fahrenheit, and the fractional parts of a degree are indicated as exactly as possible In. the plotting of the curves. Each fifth 

 decree is represented by a'slightly heavier line. The transverse interspaces inclosed by the.heavier lines represent periods of ten days each, as indicated by the dates m the 

 lefLnd side of the plate. The lighter transverse lines, intermediate between the heavier ones, are intended to represene the mean of each ten days, and the curves of tempffl- 

 Lture are plotted with reference to these lines. The left-hand vertical division is devoted to.the air temperatures for 188,. 1882 and. 1883, the middle divislori lo the BUrlace 

 vrater temper'atures for the same years. Aus permitting of ' a comparison of the two; and'the right-hand division to the water temperatures for 1884 and ,885, 



