1890.] NATURAL SCIENCES OF PHILADELPHIA. 471 
Mr. Isaac C. Martindale was elected Treasurer September 23rd 
to supply the vacancy caused by the death of Mr. Wm. C. Henszey 
which occurred September 7th. Mr. Chas. P. Perot was elected 
September 30th to fill the vacancy in the Finance Committee caused 
by the election of Mr. Martindale to the Treasurership. 
The first award of the Hayden Memorial Medal was made, on the 
recommendation of the Committee appointed to report on the sub¬ 
ject, to Prof. James Hall as a well merited recognition of the value 
of his geological work. 
A second invitation having been received from the University of 
Pennsylvania to remove to a position on the University grounds in 
West Philadelphia, the subject was maturely considered by the 
Council of the Academy and on its recommendation again declined 
by the society at a meeting held March 11th. 
Apart from the purely scientific operations of the society, the most 
important event of the year was the beginning of work on the pro¬ 
posed new building. For the details and dates of the work of 
construction as far as it has advanced reference is made to the 
report of the Curators. 
All of which is respectfully submitted. 
Edw. J. Nolan, 
Recording Secretary. 
REPORT OF CORRESPONDING SECRETARY. 
While the correspondence of the past year has been of the usual 
routine character it continues to show the steady progress of the 
Academy in its exchange relations with the scientific societies of the 
world. Each year adds many exchanges, rendering the library 
more useful to those who consult it with the view of obtaining a 
knowledge of what is being published" abroad. The study of the 
natural sciences seems to be increasing, so that in nearly every town, 
of any size, in the civilized world, societies are established and soon 
thereafter a publication of their work in serial form begins. 
During the year sixty-eight circular letters and sixtv-five cards 
of acknowledgements of the reception of our publications have been 
received from societies and other bodies. The nearly equal numbers 
of the two methods of acknowledgement is doubtless due to the fact 
that the larger portion of our exchange is sent by mail and is 
promptly acknowledged by card. 
