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During the months of January and February there is a 

 period of minimum temperature approaching 32°, averaging 

 32.75°, and rarely exceeding 34°. The constancy of the tem- 

 perature at this season is probably due in large part to the 

 equalizing effect of the ice which normally covers the stream, 

 and especially its backwaters, at this season of the year. Dur- 

 ing the early part of March the temperature rises, but the rate 

 becomes more rapid in the last part of the month. The up- 

 ward movement reaches 4(1° or 50°, in early springs, such as 

 1898, attaining the latter temperature. The average for the 

 month rises to 40.45° and the fluctuations increase in extent. 

 The rapid rise continues through April, attaining 60°-70°, and 

 averaging 60.46°. The records for this month are somewhat 

 meager for any comparisons. In May the season of maximum 

 temperature is approached and occasionally reached, as in 1896, 

 the average temperature from somewhat scanty records being 

 then 68.27°. This month is one not only of marked rise but 

 also of considerable fluctuation. The period of maximum tem- 

 perature is in full swing in June, and continues through July 

 and August and well over into September. The average rises 

 from 77.75° in June to 81.49° in August, and falls to 74.21° in 

 September owing to the decline which begins in the latter part 

 of this month. This period of maximum summer heat is fairly 

 well defined in the thermograph and continues at or near 80° 

 approximately three months, from the middle of June to the 

 middle or latter part of September. It is a time of consider- 

 able fluctuation, most of the movements being within 10°, 

 though the range for August in the five years of record was 

 from 74.3° to 89°. These fluctuations combined with the di- 

 urnal changes and the wind are effective in producing a con- 

 siderable vertical circulation of the water. 



Following the summer maximum comes the fall decline, 

 which begins late in September and is practically completed 

 in November. The greater part of the change takes place in 

 October, the average decline in that month being 16.76°, while 

 that in November is 14.55°. In some years, as 1897, the de- 



