I should fail most lamentably in my duty, Mr. Secretary, if I did not add to this reply warm thanks in the name of the Belgian Government, in the name of our scientific establishments and institutions, and in my own name, for the extreme kindness you have shown us in reserving for us until the present time all the numerous "series" and "collections" (one and all of inestimable value) which the war has prevented you from transmitting to us at the proper time.

THE NATIONAL ZOOLOGICAL PARK.

The National Zoological Park continues in popularity as a means of natural history education and as a place of recreation and amusement for the people of Washington.

The total number of animals in the park at the close of the fiscal year was 1,336, including 528 mammals, 71 reptiles, and 737 birds. Among the more important additions were two young Sumatran elephants, purchased at a cost of $5,000, for the children of Washington by a number of their friends, and donated to the institution. At the time of their arrival they were about 21 years old and were the first of their kind to be exhibited in Washington. Other important additions were a fine capybara, from the Hon. Henry D. Baker, Trinidad, British West Indies; a great white heron of southern Florida, from Dr. Paul Bartsch; and a pair of Florida bears from Mrs. A. V. N. Stroop.

Visitors to the park during the year numbered 1,964,715-a daily average of 5,383. Ninety-eight schools and classes visited the collection for instruction purposes.

Among the recent improvements are exterior cages for leopards, jaguars, and hyenas, and a new chimney for the central heating plant. A part of the creek-side drive was rebuilt, some animal houses were painted, and small improvements in the animal houses and yards were likewise effected.

The need of a new house for the exhibition of birds continues to become more urgent from year to year. An increased appropriation for the expenses of the park is also badly needed, as well as one sufficient for the purchase and transportation of animals, so that the park may take advantage from time to time of opportunities to obtain rare and conspicuous animals not before exhibited. The purchase of a frontage of over 600 feet on Connecticut Avenue, urged for several years by the superintendent, but which has not yet been considered favorably by Congress, would satisfy all the needs of the park as regards necessary expansion and better service to the public on the west side; and it becomes more and more important to secure this land, as the probability of losing the opportunity increases every year. It is also desirable to purchase a small strip of privately owned land between the park and the important highway of Adams Mill Road, because of improvements being made

at that point by the District government. The incorporation of this land within the park is of very great interest to the public.

The slight increase in the annual appropriation granted by Congress scarcely more than covered the increased cost of maintenance of the park, even by practicing the strictest economy. Lack of funds for grading banks and filling ravines has prevented the completion of work begun three years ago for the purpose of obtaining new level spaces for yards and inclosures.

ASTROPHYSICAL OBSERVATORY.

Several important investigations relating to the war, begun last year, were continued by the staff of the Astrophysical Observatory under the general direction of Dr. C. G. Abbot, in addition to the regular work of the observatory. These researches are mentioned elsewhere in this report under the heading "General considerations." At Washington work on solar radiation computations has gone on steadily, and progress has been made with the preparation of a new medium, potassium iodide, for the investigation of the rays beyond where rock salt is transmissible. A new instrument, based upon the principle of the perfect radiator, or "absolutely black body," was constructed for the purpose of measuring nocturnal radiation. such as the earth sends out to space. At the close of the year this instrument was reported as operating successfully on Mount Wilson.

In view of the fact that the total eclipse of the sun of May 29, 1919, would be visible at La Paz, Bolivia, which is not very far from the Smithsonian solar constant observing station at Calama, Chile, a successful expedition was undertaken by Dr. Abbot, with the double purpose of observing the eclipse and visiting the Calama station. Good photographs of the phenomenon and also pyranometric observations by Mr. A. F. Moore of the brightness of the sky were obtained during the progress of the eclipse. A conference was held with officials of the Argentine Government, which is likely to prove of great value in the future, in that it concerned the employment of solar-radiation measurements for weather forecasting by the Argentine meteorological service. At Calama, Chile, Dr. Abbot, in cooperation with the Smithsonian observers there, Messrs. Moore and Leonard Abbot, devised a new method of reducing solar radiation observations, so as to determine the solar constant of radiation with at least equal precision to that obtained by the older method. the advantages of the new method being (1) its independence of the variability of atmospheric transparency; (2) the time required is only one-fifth of the former period.

On Mount Wilson Mr. Aldrich continued the observations of the solar constant of radiation, and in September, 1918, made an interesting observation in cooperation with the Army Balloon School at Arcadia, Calif., on the measurement of the reflection of sun and sky radiation from layers of fog, which led him to conclude that a great horizontal fog bank reflects to space 78 per cent of the radiation of the sun falling upon it.

The preparation of Volume IV of the Annals of the Astrophysical Observatory has been in the hands of Dr. Abbot since February; it includes the results of measurements from the year 1913. Mr. Fowle has continued the work of revising the Smithsonian Physical Tables, in which he has received valuable aid from the various scientific departments of the Government and from individuals in colleges and industrial corporations.

INTERNATIONAL CATALOGUE OF SCIENTIFIC

LITERATURE.

The United States Regional Bureau of the Catalogue, supported by congressional appropriation under the direction of the Smithsonian Institution, undertakes to list and index all scientific articles appearing in the United States each year. These titles are forwarded to the Central Bureau in London, where they are incorporated with the lists from all other countries in a comprehensive catalogue of the year's scientific work of the world. The war and the chaotic conditions in Europe since the war. have greatly hampered the work of the catalogue and it has been recognized for several years that a general reorganization will be necessary when conditions become more settled.

The Central Bureau has published during the year 8 volumes of the Thirteenth Annual Issue, completing that issue, and 12 of the 17 volumes of the Fourteenth Issue have appeared. The United States Bureau has continued to gather and index the scientific titles in this country, and in some of the sciences, notably zoology, the titles have been classified far in advance of the published volumes.

It has been recently announced by the Royal Society of London, the principal sponsor of the catalogue since its inception, that after the completion of the Fourteenth Annual Issue a new financial arrangement will be necessary in order to continue the work, and scientific establishments and academies throughout the world have been asked to offer suggestions as to the best method of accomplishing this end.

NECROLOGY.

I may here express for myself and on behalf of the staff of the Institution and the National Museum the deep sense of loss caused by the death during the year of Mr. Richard Rathbun, assistant secretary in charge of the National Museum, and Mr. A. Howard Clark, editor of the Smithsonian Institution. These two men, through long connection with the Institution, contributed much to its development and their passing leaves a deep feeling of personal loss among their associates.

RICHARD RATHBUN.

Richard Rathbun, assistant secretary of the Smithsonian Institution, was born in Buffalo, N. Y., January 25, 1852, and died July 16, 1918. He received his education at Cornell University, specializing in geology and paleontology. Here he was associated with Charles Fred Hartt, professor of geology, who assigned to Mr. Rathbun the task of working up for publication a collection of fossils from Brazil, which resulted in the publication of Mr. Rathbun's first paper on the Devonian Brachiopoda of Erere, of the Province of Para, Brazil." During this work he had occasion to visit the Museum of Comparative Zoology at Cambridge, where the environment proved so congenial that he remained here for two years. During the summer months he served as a volunteer assistant under Spencer F. Baird in marine explorations on the New England coast. Through his association with Prof. Baird his connection with the Smithsonian Institution began.

In 1875 he was appointed geologist to the Geological Commission of Brazil, and for the following three years he studied the geological features of that country. On returning to the United States he was appointed a scientific assistant in the United States Fish Commission, in which service he remained until 1896.

During this period several papers from his pen appeared in "The Fisheries and the Fish Industry of the United States." During these years also he was involved in the fur seal investigation. The most important international commission to the Fur Seal Islands was the one sent out in 1896, and Mr. Rathbun was named chief advisor to Mr. Hamlin in immediate charge of the case.

In 1896 Mr. Rathbun came to the Smithsonian Institution and at the beginning of 1897 took up the duties as assistant in charge of office and exchanges, later being named assistant secretary. The following year, holding this same title, he was given charge of the National Museum, which position he held until his death.

One of the most important events during his administration of the Museum was the appropriation for and the construction of the

new Natural History Building, in which he took a deep interest, and for which he was in large part responsible. He also undertook the development of the National Gallery of Art, a feature of the Smithsonian which is mentioned first in the act creating the Institution, but which had remained dormant for lack of adequate facilities.

Mr. Rathbun was a member of many scientific societies, including several foreign connections. His bibliography contains nearly 100 titles, including the numerous papers written during his connection with the Fish Commission, and his official reports as administrator of the National Museum.

ALONZO HOWARD CLARK.

Alonzo Howard Clark, editor of the Smithsonian Institution, was born in Boston April 13, 1850, and was educated at Wesleyan University, receiving an honorary degree of M. A. in 1906. Mr. Clark's first connection with the Government service was in 1879, when he was put in charge of the United States Fish Commission Station in Gloucester, Mass. In 1881 he was made curator of the division of history of the United States National Museum, and later editor of the Smithsonian Institution, which position he held until his death on December 31, 1918. Mr. Clark was also affiliated with a number of patriotic and historical societies, being secretary and registrar general of the Sons of the American Revolution, and an officer of the Society of Mayflower Descendants and of the Society of Colonial Wars. Matters of patriotic and historical interest were Mr. Clark's chief delight, and it was through his efforts that were begun the present great historical collections in the Museum. He was especially fitted for his position as curator of this division through his wide experience in historical and genealogical work and his many connections with organizations of that nature. Mr. Clark also held a prominent place in the activities of the American Historical Association, being secretary of this organization from 1889 to 1908, and curator from 1889 until the time of his death.