672 



THE POPULAR SCIENCE MONTHLY. 



The mean for January, February, and March, for fifty-six years, is 

 35.56 degrees. The mean for the above selection is 35.23 degrees. 



From this, it would seem that the mean temperature of the first 

 three months of the year at Philadelphia is 2.66 degrees above that 

 of New York, and that the same conclusion arrived at in the preced- 

 ing instances reappears in this, viz., that there has been no change in 

 the winter climate. 



The Boston records reach back to 1780. Taking the same periods 

 as in the preceding instances, as far as these records will permit, they 

 are first, 1797 to 1803; second, 1821 to 1827; third, 1831 to 1837; 

 fourth, 1850 to 1856. It is to be remarked that these observations are 

 not all from the same station. 



TABLE, SHOWING THE MEAN TEMPEEATTJEE OF BOSTON FOE THE FIEST THEEE 

 MONTnS OF THE TEAS, JANUAET, FEBBUAKY, AND MAECH. 



The mean for January, February, and March, for eighty-six years, 

 is 29.63 degrees. The mean for the above selection is 29.66 degrees. 



The mean temperature for the first three months of the year at 

 Boston is 3.27 degrees lower than that of New York. These records 

 give no substantial reason for supposing that, during the period of time 

 to which they refer, there has been any sensible change in the winter 

 climate of that locality. 



In like manner, making a selection from the Charleston records, 

 first, from 1749 to 1755; second, from 1754 to 1760; third, from 1822 

 to 1829; fourth, from 1830 to 1836; fifth, from 1849 to 1855 which 

 date from 1738. 



TABLE, SHOWING THE MEAN TEMPERATURE OF CHARLESTON FOE THE FIEST THEEE 

 MONTHS OF THE YEAE, JANUAEY, FEBEBAEY, AND MAECH. 



In this series, again, unfortunately the observations are from dif- 

 ferent stations. They exhibit greater divergences than any of the 

 preceding cases ; but notwithstanding that, so far from invalidating, 



