16 REPORT OF THE SECRETARY. 



The work of the advisory committee has been going- on systematically 

 daring the year; papers have been read and passed upon, and many 

 applications for grants considered. 



Prof. E. W. Morley's work on the determinations of tlie density of 

 oxygen and hydrogen, referred to in previous reports as aided by spe- 

 cial api)aratu8 provided by the Institution, is approaching completion. 



The investigations undertaken by Dr. J. S. Billings and Br. S. Weir 

 Mitchell into the nature of the peculiar substances of organic origin 

 contained in the air expired by human beings, to which reference was 

 made in my last report, is still continued under a grant from the Hodg- 

 kins fund, as also are the researches by Dr. O. Lummer and Dr. E. 

 Pringsheim, of Berlin University, on the determination of an exact 

 measure of the cooling of gases while expanding, witli a view to revis- 

 ing the value of that most important constant which is technically 

 termed the "gamma" function. 



The limitations of the fund have, however, rendered it necessary, 

 with sliglit exceptions, to postpone further action in this direction for 

 the present, although it is hoped that it will i)rove practicable at a later 

 date to aid certain important lesearches to which attention has been 

 invited. 



CORRESPONDENCE. 



It is difficult to convey an adequate idea of the diversity of tlie nature 

 of the correspondence carried on immediately in the Secretary's office. 

 Without reference to the voluminous correspondence of the ]S!"ational 

 Museum, or the special correspondence of the Bureau of Ethnology, the 

 Zoological Park, and the Bureau of Exchanges, constant inquiries are 

 received from all parts of the country for information on almost every 

 conceivable topic, and requests for statistics and for information on the 

 most varying scientific subjects. This correspondence all receives care- 

 ful attention, and, as a part of the aim of the Institution in the "diffu- 

 sion of knowledge," an effort is made to give a full reply to all such in- 

 quiries, often involving an amount of labor on the part of the curators, 

 as well as of those more immediately occupied with the correspondence 

 of the Institution, out of proportion to the merits of the case. 



I desire to remark that this increase of correspondence, even if that 

 upon the business of subordinate Government bureaus alone is consid- 

 ered, calls constantly for more clerical aid and other expenses which 

 there is no appropriation for, and which practically form an added 

 burden on the limited Smithsouian fund, which it ought not to bear, and 

 to refer in this connection to what is said uiuler "Administration." 



The entries in the registry book of letters received during the year 

 number 3,6oli, but these are only the relatively important letters. 



The general card index to all the correspondence in the Secretary's 

 office, which was begun on January 1, 1893, is kept up constantly to date, 



