RECORD AND DISCUSSION OF TEMPERATURES. 



29 



paper. This correction, from consistent separate values, is +0°.99. On account 

 of the occasional omissions of observations in the hourly abstract, the daily means 

 in the Narrative for these three months are probably not reliable, the calculator, 

 as has been found on other occasions, having paid no attention to such omissions 

 in taking his mean ; the monthly means may, nevertheless, be nearly correct. 



Mean Monthly Temperatures at Van Rensselaer Harbor. 

 (Degrees of Fahrenheit's scale.) 



These values, when 

 thrown into a curve, pre- 

 sent a great regulari- 

 ty during the summer 

 months; not so, however, 

 during the winter months, 

 when the direct effect of 

 the sun is very feeble, and 

 the winds probably be- 

 come the main source of 

 the variability of tempe- 

 rature. To exhibit this 

 difference in the varia- 

 tion of the summer and 

 winter temperatures, I 

 have graphically present- 

 ed the half monthly 

 means, when the steadi- 

 ness of the summer curve 

 becomes very striking. 



Half Monthly Means. 



