OF THE Astronomical Society of the Pacific. VOL XVIII. SAN FRANCISCO, CALIFORNIA; APRIL 10, 1906. No. 107. ADDRESS OF THE RETIRING PRESIDENT OF THE BY SIDNEY D. TOWNLEY. At the close of another fiscal year in the history of the Astronomical Society of the Pacific it becomes my pleasant duty, as your retiring President, to review briefly the past progress of the Society and to make public announcement of the sixth award of the Bruce Gold Medal. This Society was founded February 7, 1889, as the result of the co-operation between amateur and professional astronomers in observing the total solar eclipse on New Year's day of that year. The Society was designed to be popular in the best sense of the word, and its progress for several years was very rapid. Later, however, a slight retrograde movement set in, but, as in the case of the planets, this did not last long, and we are happy to state that the Society is again moving with forward motion. The membership, though not large, is of a solid, permanent character, and the Publications of the Society now hold a recognized place in astronomical literature. Seventeen volumes of the Publications are now complete, and the Society's library contains fourteen hundred books and about the same number of pamphlets. Through the liberality of generous friends the Society now possesses an endowment fund, including the Life Membership Fund, of nearly $17,000, the interest from which is used for various purposes,-such as the bestowal of the Bruce Gold Medals, of the Donohoe Comet-Medals, for additions to the library, etc. In 1897, the late CATHERINE WOLFE BRUCE, of New York, gave to the Society a fund of $2,750, of which $250 was to be used for the purchase of a gold medal to be awarded, regardless of race or sex, for distinguished services to astronomy. The remaining $2,500 was to be invested, and the interest therefrom used for the bestowal of other medals, not oftener than once a year. The directors of six of the largest and most prominent observatories in the world-Berlin, Harvard, Greenwich, Lick, Paris, and Yerkes--are each asked to nominate three astronomers as worthy to receive the medal, and from the persons thus nominated the medalist is chosen by the directors of the Society. The first award of the medal was made to the eminent American astronomer, Professor SIMON NEWCOMB; the second award to one of Germany's distinguished sons, Professor ARTHUR AUWERS; the third award to an Englishman who attained eminence far away from his native isle, Sir DAVID GILL, Director of the Cape of Good Hope Observatory; the fourth award to Professor GIOVANNI VIRGINIO SCHIAPARELLI, Director of the Observatory at Milan, and Italy's most renowned astronomer; the fifth award to Sir WILLIAM HUGGINS, another of England's famous astronomers, who is still busily engaged in scientific researches at the age of eighty-two; and now it gives me great pleasure to publicly announce that the sixth award of the medal has been made to another of the eminent sons of Germany, Professor HERMANN CARL VOGEL, Director des Astrophysikalischen Observatorium zu Potsdam. Professor VOGEL has been connected with the Astrophysical Observatory at Potsdam ever since it was established in 1874, and his work has therefore been almost entirely along the line of the new astronomy, or astrophysics. He now stands with our fifth medalist, Sir WILLIAM HUGGINS, as one of the pioneer workers in this highly interesting branch of astronomy, and his many published writings, only a portion of which are to be found in the volumes of the Astrophysical Observatory, will stand as a lasting monument to his industry, ability, and constant devotion to the queen of all the sciences, astronomy. Our medalist was born in Leipsic March 4, 1842. His education was obtained at the University of Leipsic, and he became assistant in the Leipsic Observatory in 1864. From 1870 to 1874 Doctor VOGEL was director of Herr von BULOW's private observatory at Bothkamp, near Kiel. From 1874 to 1882 he was associated with the commission which had in charge the building of the Astrophysical Observatory at Potsdam, and in the latter year, when this magnificent institution. was turned over to the Government by the commission, Doctor VOGEL became its first director, and still remains in that position. The observatory at Potsdam was built and is maintained by the Prussian Government. It was at first indirectly connected with the University Observatory at Berlin, but it now has no connection with any educational institution, although some of the astronomers of the observatory lecture at the University of Berlin. The observatory is located on the summit of a hill, amid spacious, heavily wooded, and well-kept grounds, just outside of Potsdam, at a distance of about fifteen minutes' walk from the railway station. The general construction of the observatery may be seen from the illustration presented herewith.1 The principal instruments of the original observatory are three refractors,-one of 30 centimeters (12 inches) aperture, objective by SCHROEDER, mounting by REPSOLD, in the central dome; one of 21 centimeters (8 inches) by GRUBB, in the western dome, used chiefly for the observation of sun-spots; and a 13-centimeter (5 inches) telescope by STEINHEIL, in the eastern dome, used for spectroscopic. observations of the Sun and for photometric work. It should be stated that the Potsdam Observatory was intended originally for solar work, and it was indeed formerly called the Sonnenwarte, or solar observatory, as distinguished from a Sternwarte, or star observatory. One of the rooms of the observatory contains a very large and accurately constructed spectrometer, by BAMBERG, which is used for study of the solar spectrum, the rays of light from the Sun being brought to the collimator in a horizontal direction by means of a heliostat. The rooms of the observatory contain many smaller instruments and pieces of apparatus. In 1889 it was decided by an international conference which met in Paris to take up, by co-operation among a num The photographs from which this cut and the one of Doctor VOGEL were made were kindly loaned by Prof. LEUSCHNER. Another view of the observatory and a short descriptive article by Prof. LEUSCHNER may be found in Volume IV of these Publications. ber of observatories, the almost herculean task of photographing the entire sky and making catalogues and charts of the stars contained upon the plates obtained. The Potsdam Ob servatory engaged to take part in this work, and was assigned the zone lying between 31 and 40° of north declination. For this purpose a new photographic refractor of 45 centimeters (13 inches) aperture was provided and mounted in a dome detached from the main building. The instrument is in fact a doublet, a visual telescope of 23 centimeters (9 inches) being provided for the purpose of guiding the photographic telescope. Again in 1900 a very material addition was made to the equipment of the observatory by the acquisition of a great refractor having a photographic objective of 80 centimeters (31.5 inches) and a focal length of 12 meters (39 feet), and also a visual telescope with aperture of 50 centimeters (20 inches) and focal length of 12% meters (41 feet). This instrument is used chiefly for the determination of the velocities of stars in the line of sight, and is located in a dome situated on a second hill at some little distance from the main building. The unfinished dome may be seen in the illustration.1 Besides Director VOGEL there are a number of astronomers and assistants connected with the Potsdam Observatory, and an atmosphere of intense scientific activity prevails there. Fourteen well-filled quarto volumes have been issued in the regular series of publications of the Observatory. The investigations printed in these volumes cover a considerable range of problems in astrophysics. Among these may be mentioned observations of sun-spots, investigations of the solar spectrum, studies of the spectra of the planets and the fixed stars, photographic observations of the velocities of the stars, observations of variable stars, photometric determinations of stellar magnitudes, etc. In addition to the regular series of publications three volumes have been issued giving the results of the work undertaken in connection with the international plan to photograph the entire heavens, mention of which has already been made. These volumes contain the photographic magnitude and ap 1 An illustration showing the building after it was completed may be found in Volume XI (opposite page 215) of these Publications. |