These are the values of the angular diameters of the satellites of Jupiter as seen from the earth. To reduce these to Jupiter's mean distance these values are to be multiplied by 0.79 which give for the final values

For the sake of comparison these values are recorded in the following table together with those given by ENGELMANN, STRUVE and HOUGH, and the last column contains some results kindly furnished by Professor BURNHAM with the 36-inch on the same date (August 7th) as the last of the series by A. A. M.

It was found impossible to see the reappearance of the fringes on increasing the distance, yet the results of Table I show that the disappearance could still be sharply marked. Indeed the concordance of the observations made under different circumstances on different nights was even closer than was expected. With a larger telescope both the brightness of the fringes and their dis

tance apart will be increased, and it may be confidently predicted that the accuracy will then be even greater.

The values given in the second column "ENGELMANN" are probably more reliable than the succeeding ones, but it is well worth noting that the differences between the results obtained by interference agree with the others quite as well as these agree with each other.

It should also be noted that the distance between the slits was about four inches. It may therefore be stated that for such measurements as have just been described, a telescope sufficiently large to admit a separation of four inches-say a six-inch-suitably provided with adjustable slits is fully equal to the largest telescopes now used without them.

It is hoped that within a few months the 36-inch equatorial will be supplied with a similar apparatus and observations begun for the definitive measurement of the satellites of Jupiter and Saturn and such of the asteroids as may come within the range of the instrument.

In concluding, I wish to take this opportunity in expressing my appreciation of the courtesy of Director HOLDEN in placing all the facilities of the Observatory at my disposal, and of the hearty co-operation of all the astronomers of the Observatory, especially the valuable assistance of Professor W. W. CAMPBELL in making the observations.

MT. HAMILTON.

THE UNIVERSITY OBSERVATORY OF STRASSBURG.* The accompanying cuts are copied from Lieut. WINTERHALTER'S Report on European Observatories, by the kind permission of the Superintendent of the U. S. Naval Observatory (See Publ. A. S. P., vol III, page 40). The short account here given is condensed from Lieut. WINTERHALTER'S report, and from other sources.

When the Germans took possession of Alsace, it was determined to create a University of the first class in the chief city of the province, and the installation and equipment of the new institution was on the most liberal scale. The most celebrated scholars of Germany were called to the University and were given carte blanche in the material provisions for the wants of their respective departments.

Dr. A. WINNECKE, then Vice-Director of the Imperial Observatory at Pulkowa, was made Professor of Astronomy in the University and Director of the new Observatory, and every detail of the buildings and instruments was left to him. The Observatory of Strassburg (begun in 1877) may be said to represent the matured ideas of European astronomers with regard to the construction and installation of instruments at the date in question, and it was designed and largely executed under the direct supervision of Prof. WINNECKE himself, who was universally acknowledged to have especial gifts in this, as in so many other directions.

I may be allowed to add that the designs for the Lick Observatory were being studied in the years 1874-1879, and that during a part of that time I had the great benefit of Professor WIN

* Professor E. BECKER, Director.