32 
PHILOSOPHICAL SOCIETY OF WASHINGTON. 
Table II. 
Average Attendance at Ordinary Meetings for Each Half-Month, 
Compiled from Records for 11 Years, 1875-1886. 
October, first half-.-.— 39.8 
“ second half- 40.5 
Xovember, first half__ 45.0 
‘‘ second half__ 43.9 
December, first half_ 43.2 
“ second half__40.8 
January, first half_ 31.5 
“ second half__ 45.9 
February, first half_ 41.3 
“ second half__41.0 
March, first half_40.0 
second half__ 40.3 
April, first half__ 48.0 
“ second half_ 40.3 
May, first half_ 37.5 
“ second half__ 37.3 
June, first half.. 33.7 
“ second half_ 28.6 
In compiling the statistics of papers or communications before 
the Society, everything has been included which was prepared or 
announced beforehand, whether offered independently or as part of 
a symposium, but the remarks of one member upon the communica¬ 
tion of another have not been included. The impossibility of other¬ 
wise making a consistent distinction has led to the inclusion of every 
exhibition of apparaius and every reading of a letter upon a scien¬ 
tific subject. The biographical memoirs of deceased members which 
have from time to time been read are included, but not the com¬ 
memorative resolutions. 
The Society has listened in 17 years to 713 papers, as thus de¬ 
fined, an average of 42 per year. Six hundred and ninety- 
tv/o of these have been presented before ordinary meetings, an 
average of 41 per year. There have been in the same period 
277 ordinary meetings, and the average number of papers per 
meeting has been 2 5. The number of ordinary meetings and 
the total number of meetings per year were both somewhat greater 
in the earlier history of the Society than in the later, a tendency 
having developed to omit one or two meetings in June. There 
were also more pampers read in the earlier years than in the 
later, and the diminution in papers has been slightly greater than the 
diminution in the number of meetings, so that the average number 
of papers per meeting has fallen off from 2.8 to 2.4. 
For the purpose of exhibiting the subjects which have received 
the attention of the Society, the entire series of papers has been 
grouped in ten classes, the discrimination being based on the titles 
and abstracts, and, to some extent, in the absence of abstract, on the 
memory of the compiler. Papers belonging properly to two or 
