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.) 



1853 September . . + 17.16 1854 July . . -f 38.19 

 October . . + 1.62 August . . . +31.82 

 November . . . 22.39 September . . + 9.74 

 December . . . 25.46 October . . . 8.78 



1854 January . . . 29.21 November . . . 21.52 

 February . . . 32.65 December . . 36.79 

 March . . . 36.79 1855 January . . . 27.23 

 April . . - 7.69 February . . 20.22 

 May . . . . +13.45 March . . . 32.98 

 June . . +30.12 April . . 13.01 



If we unite the temperatures for the same months in one mean, we obtain the 

 following mean temperatures for each month of the year : 



1853-54 September 

 October 

 November 

 December . 



1854-55 January . 

 February . 



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. 



+ 13.45 



3.58 



21.95 



31.12 



28.22 



26.43 



1854-55 March . . . 34. 85 



April . . . 10.35 



1854 May . . +13.45 



June . . . +30.12 



July . . . +38.19 



August . . . +31.82 



HALF MONTHLY MEANS. 



20- 



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