LEADING OBSERVATORIES.

By means of the statistics compiled in the recent investigation of the United States Naval Observatory at Washington, it is possible to compare the Harvard Observatory with the other leading observatories of the world. The Naval Observatory has the largest annual income--about $85,000. The National Observatory of France is second, with an income of $50,000, and the Royal Observatory at Greenwich, third, with $49,000. The Harvard Observatory and the Imperial Observatory of Russia, at Pulkowa, receive $46,000 yearly. The richest private Observatory is that at the Cape of Good Hope with an annual revenue of $33,000. In the relative values of their equipments the leading observatories rank differently. Washington has buildings and instruments valued at $856,500 but both the Yerkes and Lick Observatories have apparatus worth half a million dollars. Harvard is far behind in this respect. The estimated value of the buildings at Cambridge is $52,000; at Arequipa, $12,000; of the instruments at Cambridge, $20,000; and of those at Arequipa, $50,000--a total of $134,000.

The largest refracting lens in use is that of the great Yerkes telescope, with an aperture of forty inches. The Lick lens is thirty-six inches in aperture; the Royal Astrophysical Observatory at Potsdam has recently acquired a thirty- one inch photographic refractor; and the Pulkowa Observatory has a thirty inch lens, made by the late Alvan Clark of Cambridge. Greenwich and Washington have telescopes with apertures of twenty-six-inches. The largest instrument in the possession of the Harvard Observatory is the twenty four inch Bruce photographic telescope, mounted at Arequipa.

The staff of the Harvard Observatory is larger than that of any other. The following statistics are for the year 1899.

Astronomers -- Harvard, 6; Greenwich, 5; Washington, 4.

Assistant astronomers--Harvard, 13; Greenwich, 5; Washington, 3.

Computers--Harvard, 18; Greenwich, 24; Washington, 8.

The men engaged in research at the Harvard Observatory are freed, as far as possible, from computing and similar mechanical work. The number of assistants and computers is large but it is still insufficient. As a result a great amount of data has been accumulated which, except for compilation, is ready to be published. The incomplete work now in progress would make up twenty-eight volumes of the Annals.

The work done by the different observatories varies greatly in character. Private observatories attend chiefly to some special research for which their equipments or situations are favorable. At Greenwich the work consists of testing chronometers for the navy; of transit reductions and determinations of time. The observatory at Pulkowa is pre-eminent for the extreme accuracy of its observations. To this end the apparatus is of a special design and of great accuracy; the methods adopted there sixty years ago are said still to be far in advance of those at present existing in any other government observatory. The Kiel Observatory is the European centre for the announcement of astronomical news.

Harvard holds a position in this country similar to that of Kiel in Europe. The routine work done here, on a scale impossible at smaller stations, has been the chief cause of the reputation which the Harvard Observatory has won. Especially well-known is the practice of photographing the heavens to secure a permanent and comprehensive record of star-movements. The number of photographs which have so far been secured with the various telescopes is as follows: Eleven inch Draper, 12,872; eight inch Draper, 25,- 890; thirteen inch Boyden, 10,214; eight inch Bache, 26,339; twenty-four inch, Bruce, 4,767.

The Observatory is handicapped by insufficient buildings, and by a lack of proper instruments. It ranks among the greatest observatories of the world because of the scope and the general value of its scientific investigations.