Ixxv 



Running over former records, I find the unexpected fact that for the last 

 ten years we have had regular alternations of mild and cold winters. The 

 cold winter of 1S72-3 was followed by the mild one of 1873-4, although 

 this was only i°.3 above the average; but all the following winters show 

 between five and seven degrees deviation from the normal, as is shown in 

 the following table : 



i — 7". 2 1878-79 28°. 4 — 5°.l 



1 .3 1879-80 39 .1 + 5 .6 



6 .6 1880-81 26 .6 — 6 .9 



6 .7 1881-82 39 .1 + 5 .6 



2 .8 1882-83 28 .9 — 4 .6 



The normal winter temperature is 33°. 5 How these values can be har- 

 monized with the supposed meteorological periods of 10 or 11 years, or 

 how it can be explained, I must leave to others. To increase the difficulty 

 I must add that in the previous ten years, from 1862 to 1872, about all the 

 winters had temperatures differing little from the normal. 



May 15, 1882. 



The President in the chair. Ten members present. 



Mr. Nipher made a final report on the cost of removal to Wash- 

 ington University, and at his request the subscription list and 

 vouchers for expenditures were referred to a committee consisting 

 of Dr. Sander and Mr. Tivy. The accounts were reported cor- 

 rect and the committee was discharged. 



Mr. Nipher announced the completion of his report on the 

 magnetic work of iSSi, and the report was presented to the 

 Academy. 



yune 5, 1882. 



The President in the chair. Nine members present. 



Dr. Engelmann reported that 



the past month was among the coldest Mays since 1837, when his obser- 

 vations began. The mean temperature for May is 66°. 3. Two years 

 ago the May temperature was 71°. 3 and only last year it was 71°. 4, these 

 being the highest May temperatures observed. This year, however, it was 

 60°. 7. Only twice has the temperature of May fallen as low as this. In 

 1S38 and 1867 it was as low as 60°. 5. It is interesting to observe that in 



