Each vetticaT interspace represents one degree Fahrenheit; and the fracdonal parts of a degree are indicated as exactly as possible in tlie plotting oT tlie curves. Eackfafli 

 degree is represented by a slightly heavier Une. The transverse interspaces inclosed by tiie heaviec'Jines represent peciods of tea days each, as .indicated by the dates oa. flie 

 left-hand side o£ Ihe plate. The lighter transverse lines, intermediate between the heavier ones; are intended £0 represent the mean of each ten days, and the curves of tempep- 

 ature are plotted -with reference to these lines. The left-hand vertical division is devoted to the air temperatures for 1881, 1S82 and 18S3. the middle diviaoa to the surface 

 ■water iemEeratures fca the same yeais. thus pennitting of a companacn of ih& two and the ughtiiand. division to the water temperatures for i S84 and 1885. 



