206 TRANSACTIONS OF THE [jUNE 9, 



Mr. E. B. Dunn, of the U. S. Signal Service, read a paper 

 entitled 



THE CHANGE IN OUR CLIMATE, AND THE CAUSE. 



(Abstract.) 



The question of a change in our climate, whether viewed in a 

 scientific or purely physical sense, must be of more or less interest 

 to each of us. 



It is the general belief that our climate is undergoing a change, 

 and the subject has been the cause of much discussion by the 

 press and public, especially during the past two years. Scien- 

 tifically, little has been done to prove to what extent the change 

 has been. 



By the kind permission of the Academy, I will present a few 

 facts and figures that will show the amount of the change, and, 

 I hope, lead to a solution of the cause, not alone in this vicinity, 

 but throughout the entire country. 



The question of a change in climate is not a new one ; it has 

 been discussed in this country and Europe in past years, without 

 reaching any definite conclusion; but the present circumstances 

 differ materially from those formerly investigated, and a research 

 into the subject may prove far more beneficial to American in- 

 dustries (principally agriculture) than is generally supposed. 



To establish as a fact the change of a climate from any cause, 

 whether it be apparent or occult, necessitates years of careful ob- 

 servation. We must therefore deal cautiously with the few facts 

 at hand before coming to any definite conclusion as to the change 

 in our climate being a temporary or permanent one. 



The most noticeable change that has occurred in this vicinity 

 has been the warm winter months of 1888, 1889, and 1890. 



According to the figures of the Signal Office in this city, the 

 highest annual mean temperature for the past 19 years was 53.5° 

 in 1889, and the lowest, 48.6° in 1875 ; confining the range of 

 annual mean temperature to 4.9°, and making the annual mean 

 51.3°, the records show that since 1876 there has been an in- 

 crease of heat in this city, except for the years 1885, 1886, and 

 1888, those years showing a slight deficiency. 



Not a single year up to 1883 did we receive our full amount of 

 heat; in most cases the winters were long and severe. At the 

 close of 1883 the annual mean temperature just equalled the 

 normal ; since then, except in the three years mentioned, there 

 has been a surplus, and in the last two years the increase was 

 most marked. In comparing the year 1875, which is the coldest 

 on record and has a deficiency of 1,039° mean temperature, with 

 the year 1889, which is the warmest on record and has an excess 



