Each "vertical interspace represents one degree Fahreiiheir, and the fractional parts of a degree are indicated as" exactly as possible in the plotting of die curves. Each; fifth 

 degree isrepresented by a slighdy heavier line: The transverse interspacesinclosedby. the heavier lines representperlods of ten days each, as indicated by the dates on the 

 left-hand 'side of the plate. The .lighter transverse rineS,rititecniediate' between the heavier ones, are intended to represent the mean of eacli ten days.'and-tiie curves of temper- 

 ature' are plotted with reference to these lines;>'-'Ehe.left-hancf vertical division-is devoted to the air temperatures for iSSi, 1882 and 1883, the. middle division to the surface 

 water temperatures foic tie same years, thus peCB^jfeg of a comparison of thetwo; and -the right-iiand dijdsion to the water temperatures for i£&\ and 1,885. 



