The publications of the bureau issued during the year comprise two annual reports with their accompanying papers, and two bulletins. In press or in preparation at the close of the year were three annual reports and five bulletins. The bureau library was enriched by the addition of 1,078 volumes, among them 20 volumes of Bibles and portions of the Bible in American Indian languages.

INTERNATIONAL EXCHANGES.

The total number of packages of governmental and other documents handled by the International Exchange Service during the year was 301,625, an increase of 25,869 over the previous year. This figure, however, still shows a decrease as compared with the total handled in 1914, owing to the suspension of shipments to 10 countries involved in the European war. Efforts have been made to resume shipments to certain of these countries, which have met with some degree of success in the case of Germany and Russia.

The Exchange Service has continued its policy of international helpfulness by assisting governmental and scientific establishments to procure publications especially desired both in this country and abroad. One instance showing the value of this policy may be cited. The Pan American division of the American Association for International Conciliation, of New York, wished to assemble a collection of several thousand volumes of North American origin for presentation to the Museo Social Argentino at Buenos Aires. Through the Exchange Service the matter was brought to the attention of the proper establishments and several hundred governmental and other publications were received for the proposed collection.

The number of sets of United States governmental documents sent through the Exchange Service to foreign countries has been reduced from 92 to 91, owing to the discontinuance of shipments to the government of Bombay at the request of that government.

NATIONAL ZOOLOGICAL PARK.

The National Zoological Park is becoming each year a greater and greater attraction to the public, and as its collections increase so does its value become of more importance as a source of information to the zoologist in his study of animal life.

There is now in the park a total of 1,383 individual animals, representing 360 species, as shown by the detailed census in the report of the superintendent.

Among the recent accessions may be mentioned a pair of young lions, a pair of Siberian tigers, a great red kangaroo, several monkeys, and a number of interesting birds, but the newly acquired ani

mal that seems most popular is a male chimpanzee, about 4 years old, from the forests of French Congo.

The number of visitors during the past year was 1,157,110, as compared with 794,530 in the year preceding. This included 161 schools, classes, etc., numbering 8,679 individuals.

Recent improvements include the construction of a hospital and laboratory building and the grading of some ridges and gullies to secure additional building sites and paddocks for the deer and other large animals.

As mentioned in previous reports an appropriation was made in 1913 for the purchase of several acres as an extension to the western boundary of the park, but legal proceedings and complications incident to adjustment of values and benefit assessments caused such delay that the appropriation, not being a continuing one, lapsed on June 30, 1915, and Congress has failed to renew the allotment for this much desired improvement.

Many important needs are urged by the superintendent, some of which I have mentioned year after year. One of these is an aviary building for the birds now being housed in temporary quarters greatly deleterious to their health. Other needs are a building for the elephants, hippopotami, and similar animals; an ape house; a reptile house; a pheasantry; an ostrich house; an aquarium; and an insectary; also a gatehouse and a permanent boundary fence.

THE ASTROPHYSICAL OBSERVATORY.

Observations of the solar constant were continued at Mount Wilson, Cal., from July to October, 1915, and were begun again in 1916. During the year there was published the results of solar-constant observations made under Prof. Pickering's direction at Arequipa, Peru, since August, 1912, with a silver-disk pyrheliometer lent by the Smithsonian Institution. These observations confirm the variations of the sun observed at Mount Wilson. An interesting feature of the Arequipa observations was the fact that the volcanic eruption. of Mount Katmai in 1912, which produced a great deal of dust over the northern hemisphere, apparently had no effect on the atmosphere south of the equator.

The results of observations at Mount Wilson in 1913 and 1914 on the distribution of radiation along the diameter of the sun's disk were published during the year. It is thus shown that the average distribution over the disk varies from year to year as well as from day to day.

Observations have been continued on the transmission of rays of great wave length through long columns of air, which it is expected will be of much interest in studying the earth's temperature as dependent on radiation toward space.

After several years of experimenting the Astrophysical Observatory has constructed an instrument called the pyranometer, designed for measuring the intensity of sky light by day and of radiation outward toward the sky by night. A full account of this instrument has been published in pamphlet form. The pyranometer may prove of advantage in botanical investigations in forests and greenhouses, since it can measure radiation in deep shade as well as in the full sun. The Institution has made an allotment from the Hodgkins fund for carrying on solar-constant work at some suitable place in South America. Throughout the year, for several years, it is intended to continue observations at Mount Wilson in California and at the South American station with a view to determine the dependence of the earth's climatic conditions on the sun's variation of radiation. In addition to his solar-constant work the director of the observatory has given considerable attention to experiments at Mount Wilson with solar cooking apparatus "comprising ovens heated by oil under gravity circulation maintained by heat collected by a concave cylindric mirror of about 100 square feet surface." These experiments were not concluded at the close of the year.

INTERNATIONAL CATALOGUE OF SCIENTIFIC
LITERATURE.

The International Catalogue of Scientific Literature, the United States bureau of which is administered by the Smithsonian Institution, was organized in 1901, and since that date 17 volumes of references to scientific literature, one for each of 17 branches of science, have been published each year. During the past year 24,160 classified references to American scientific literature were prepared by the United States bureau, bringing the total number of references to the literature of this country since the inception of the catalogue up to 369,509.

As stated in last year's report, the war in Europe caused considerable financial embarrassment to the publication of the catalogue owing to the impossibility of collecting subscriptions from several of the countries involved. The generosity of the Royal Society of London in making up this loss of income made possible the publication of the thirteenth annual issue, and this year a request was made for assistance from the United States. Your secretary succeeded in interesting the Carnegie Corporation, of New York, in the project and through the generous assistance of that establishment it was made possible to publish the fourteenth annual issue.

The value to science of this catalogue is universally recognized, and it is the opinion of scientists everywhere that any lapse in its publication would be a real calamity, as shown by the action of the Inter

national Council of the Catalogue in voting to extend the work to at least 1920.

NECROLOGY.

James Burrill Angell, doctor of laws, died April 1, 1916. He had been a regent of the Institution for a quarter of a century, from January 19, 1887, to January 15, 1912, when he resigned on account of age and inability longer to attend meetings of the board. He was born at Scituate, R. I., January 7, 1829, and through his long life as a journalist, an educator, and a diplomat he served his country faithfully in many positions of honor and trust.

He began his career as a professor of modern languages at Brown University, was a journalist during the period of the Civil War, president of the University of Vermont 1866-1871, president of the University of Michigan 1871-1909, United States minister to China 1880-1882, and minister to Turkey 1897-98, and served on several important treaty commissions. In accepting his resignation as a regent in 1912 the board recorded its appreciation of his long and faithful service to the Smithsonian Institution.

Respectfully submitted.

CHARLES D. WALCOTT, Secretary.