REPORT OF THE SECRETARY. ol 
As stated in the two preceding annual reports, it is highly desirable 
to continue the solar observations throughout the year, and this can 
be accomplished by observing during the winter and spring months 
in southern Mexico, where a cloudless sky and high altitude of the 
sun may be had, although during those months bad observing condi- 
tions occur in the United States. Hitherto lack of funds has pre- 
vented a Mexican expedition. 
The work of the observatory is receiving highly favorable notice 
both in this country and abroad, its results being employed by our 
own Weather Bureau and by foreign investigators as a basis for 
their measurements on the radiation of the sun. 
INTERNATIONAL CATALOGUE OF SCIENTIFIC LITER- 
ATURE. 
The purpose of the International Catalogue of Scientific Litera- 
ture is to collect and publish in 17 annual volumes a classified 
index of the current scientific publications of the world. This is 
accomplished by the cooperation of 32 of the principal countries 
of the world, each having a regional bureau which prepares the 
data necessary and indexes all scientific literature published within 
its domain. The material thus prepared is forwarded to a central 
bureau in London for publication in the annual volumes. 
The various subscribers throughout the world bear the entire cost 
of printing and publishing by the central bureau, each country tak- 
ing part in the enterprise bearing the cost of indexing and classify- 
ing its own publications. The 17 annual volumes combined contain 
between 10,000 and 12,000 printed pages. 
The regional bureau for the United States furnishes yearly about 
30,000 classified citations to American scientific literature, which is 
between 11 and 12 per cent of the total work. 
Millions of dollars are being spent each year in scientific investiga- 
tion and many of the foremost men of the day are devoting their 
entire time to such work. The results of their labors find publicity 
through some scientific journal of which there are over 5,000 being 
regularly indexed by the various regional bureaus, and over 500 in 
the United States alone. In addition to these periodicals are hun- 
dreds of books and pamphlets, all of which the International Cata- 
logue aims to index in its yearly work. 
The International Catalogue furnishes in condensed, accurate, and 
permanent form a minutely classified index to all of these publica- 
tions. It is necessary for each paper to be carefully studied by a 
person competent to thoroughly understand the subject treated, as 
the method of classification actually furnishes a digest of the con- 
tents in addition to the usual bibliographisal data. The catalogue 
is to science what the legal digest is to law. 
