GENERAI, MEETINGS. 
31 
The Anthropological Society was organized February 17, 1879, and 
has now a membership of 154. The Biological Society was organ¬ 
ized December 3,1880, and has a membership of 174. The Mathe¬ 
matical Section of the Philosophical Society held its first meeting 
March 29,1883. The Chemical Society was organized January 31, 
1884, and now numbers 44 members. During the two years fol- 
lovv^ing the institution of the Anthropological Society our Society 
witnessed maxima in the accession to membership, in the total 
membership, in the attendance, and in the ratio of attendance to 
membership. During the two years following the foundation of 
the Biological Society each of these quantities reached or passed a 
minimum. The year of the organization of the Mathematical Sec¬ 
tion was characterized by an increase of attendance, but not of 
membership. In the four years elapsed since the beginning of the 
Chemical Society our membership and attendance have steadily 
increased, their ratio remaining constant. If the relation of our 
record to the Biological Society only were considered, it would be 
easy to infer that our Society suffered from the formation of another 
scientific society, but a contrary inference would be drawn from a 
comparison of our record with the histories of the Anthropological 
and Chemical Societies, and in view'of all the facts it appears proper 
to conclude that our membership and attendance have not been 
materially influenced by the organization of the other societies. 
The data of attendance have been classified by months likewise 
and finally by half-months, with the result which appears in Table 
II. The data cover a period of 12 years, but are somewhat imper¬ 
fect. To diminish the error from imperfection of record, a general 
correction for annual phase was applied to all the observations— 
that is to say, they were all reduced to consistency with a mean 
attendance of 40. Only ordinary meetings for the reading of papers 
were included, and the year 1887 was omitted because the attend¬ 
ance appeared to be greatly affected by the change of quarters 
(March 26) from the Army Medical Museum to the Assembly Hall 
of the Cosmos Club. 
