^ch vendcal interspace represents one degree Fahrenheit, and the fractional parts of a degree are indicated as exactly as possible in the plotting ot tlie curves. Each fifdi 

 cteee is represented by S sligMy heavlef line. The transverse interspaces inclosed by die heavier lines represent periods of ten days each, as indicated by the dates on the 

 lefiShand side of tlieBpIate. ThellgliteB transverse lines, intermediate between die heavier ones, are intended to represent die. mean of each ten days, and the curves of temper- 

 ature are plotted "aith reference to "AesB lines. The left-hand vertical division is devoted to the air temperatures for i88i, 1882 and 1883, the middle division to the surface 

 ■water temperatures fotf the same years, thus peianittmg of a comparison' of the two; and die right-hand division to die water temperatures' for 1 884 and j 885. 



