CONTRIBUTIONS TO ASTRONOMY

Not being connected with undergraduate departments, the work of the Harvard Astronomical Laboratory, famous in all parts of the world for the valuable results of its observations, is not familiar to undergraduates. The studies of the Observatory might be roughly classified as Position, Motion, Brightness, Spectrum, and Color, all elements in the task of finding, classifying and determining the composition of the heavenly bodies.

Seventy-Five Volumes Published.

As no teaching is done at the Observatory, all the time of the staff there is spent in research work which is recorded in the seventy-five quarto volumes published by the institution. It is part of a great international plan for the purpose of studying the heavens and all of its work has not so much local as international significance. A society representing all the leading nations divided the sky into about twenty zones for the purpose of thorough observation and two of these zones were taken by the Harvard Observatory.

Positions of Stars Studied.

As to the study of the positions of the stars in these two zones, Professor Rogers and Professor Searle spent more than twenty years in the work. Each was assisted by three of four computers. The results of the observations and computations in regard to the position of the stars fill about twelve quarto volumes. The motions of these same bodies were also carefully studied and the records of this study fill two more volumes.

Two Million Measurements.

The measuring of the brightness of the stars has occupied a large part of the time of the Observatory for thirty years. In this time, more than two million measurements were made of some 80,000 stars. In carrying on this work, a stations has been maintained in the southern hemisphere, at Arequipa, Peru, and the stars in that portion of the heavens have been observed by the same system as that used here in the northern hemisphere. As a result of the work of these two stations, a scale of magnitudes has now been established and accepted by international consent.

Draper Memorial Fund.

The establishment of the Henry Draper Memorial Fund has made possible the study of the spectrum of the stars. The Observatory has been eminently successful in this work and a classification was drawn up which was accepted last summer by the International Solar Union at Bonne to be the authentic system. In this work, a large number of new stars, variables and other peculiar objects have been discovered. A catalogue classification of 200,000 stars is now being prepared at the Observatory by Miss Cannon at the rate of 5,000 a month. This will fill eight volumes of the annals.

Color a Valuable Element.

Until recently, the color of stars has had but little scientific value. It has now become an exact science, the chief working principle of which is to photograph the star first by yellow light and second by blue light. A vast piece of work in this field is now in progress which will make, when finished, a valuable contribution to the laws of the universe.

Vast Routine of Duties.

It may be seen from the above account that the work at the Harvard Observatory differs from that of other observatories in that great pieces of routine work are undertaken by it,--work which occupies the entire time of several observers for many years. At present, the observers are finishing up the matter of the motions of all the stars in the two zones. This work is almost ready for publication. The work of ascertaining the color of all the stars has been started within the last year. The most recent publications are Volume 76, Part I, by Professor King, showing that distant stars are redder than nearer stars; and Volume 78, Part I, by Professor Bailey, which is a study of the variable stars in the clusters