1890.] NEW TORK ACADEMY OF SCIENCES. 207 



of 845° mean temperature, we find a difference of 1,874' mean 

 temperature between the extremes of these years ; such a change 

 can hardly be realized, and would be instantly doubted were it 

 not for the figures of most reliable records. 



During the 3'ear 1875 the temperature in this city ran below 

 the freezing point on 114 days, and on 37 days remained below 

 for the entire day ; the lowest temperature was 6° below zero, 

 ■which occurred on the 10th day of January, and was, by the way, the 

 lowest temperature ever recorded by the Signal Office in this city. 



Now, to compare the year 1889, we find the temperature re- . 

 cording below the freezing point on 59 days only, 55 days less 

 than 1875, and on 14 days only did the temperature remain be- 

 low freezing for the entire day, 23 days less than 1875 ; the cold- 

 est day was February 24th, 2° above zero. 



The more noticeable change and increase of heat began with 

 the month of November, 1888, and continued unremittingly to 

 the present time, except during the months of July, August,, 

 and September. The greatest excesses take place during the 

 winter mouths ; the month of August shows a deficiency, and, 

 strange to say, the mean temperature for that month for tiie past 

 eight years has been below the normal; and the months of July 

 and September show a loss of heat during the past two years, but 

 not of such marked degree as August. 



Since January 1st, this year, we find the same excess taking 

 place, only more rapidly and to a greater extent than in 1889; in 

 that year the surplus heat for January was 211°, while the same 

 month this year shows an excess of 328'' mean temperature above 

 the normal, an increase of 156° for February, 44° for March, and 

 152° for April, the month of May closing with an excess, since 

 January 1st, of 789°, or 253° more than for the same period of 

 1889. This great increase enables us beyond a doubt to say that a 

 change has and is still taking place in our climate, and assures 

 us of two things: first, that the greatest excess of heat occurs in 

 our coldest months, modifying them to such an extent as to 

 compare favorably with our Southern winters; second, that the 

 months of July, August, and September have a tendency to be 

 cooler than the mean. There must be considerable comfort de- 

 rived from the latter fact, for should the heat continue to be 

 received at its present rate of increase throughout the warm 

 months, it would be almost unbearable. But it is my belief that 

 the summer months will greatly reduce the surplus heat already 

 received; if not, the winter months must be decidedly colder 

 than usual to have the counterbalancing effect of cutting down this 

 year's excess and bringing the annual mean temperature within 

 the range of the past nineteen years, otherwise the theory that 

 our climate is changing will be greatly strengthened. 



