March 9, 1894. 
SCIENCE: 
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THE PROGRESS OF ASTRONOMY IN 1893. 
BY GEORGE A. HILL, WASHINGTON, D. C. 
THE year 1893 beheld a most rapid progress in all 
branches of astronomy. It will be our purpose to 
call attention to the more important advancements that 
have been made, and also to items of especial interest, as 
a complete resumé of the subject would reach far beyond 
the limits of this article. 
In instrumental equipment we have passed beyond our 
present apparatus, and we are launching out upon a most 
wonderful improvement in instruments and their ac- 
cessories: The mounting for the great telescope for the 
Yerkes Observatory has been completed, and was on ex- 
hibition at the World’s Fair. The tube will be at least 
sixty-four feet long. The object glass of forty inches 
clear aperature is a reality, and Alvan Clark, its makers 
has said that it will be finished the coming summer. 
Brashear has completed the star spectroscope, and is 
about to commence the solar spectroscope and the spectro- 
heliograph. 
Professor Pickering has received from the maker, Clark, 
a twenty-four inch photographic telescope, the gift of Miss 
Bruce, of New York. ‘The telescope will be mounted on 
a high mountain of the Andes, in Peru, and from that 
elevation its whole energy will be concentrated upon a 
photographic map of the heavens. 
Father Algte has just departed for Manila, in the 
Phillippine Islands, at which point he will install an astro- 
nomical observatory. The most important instrument 
that accompanies Father Algue is an equatorial, with an 
object glass of nearly twenty inches clear aperature. The 
mounting is by Saegmuller, of Washington, D. C., the 
object glass by Mertz, of Munich, and is a companion to 
that at Strassburg, andthe one at Milan, which has been 
productive of so many interesting observations in the 
hands of Schiaparelli in his measurement of double stars, 
and the markings upon the planets, especially Mars. It 
was the writer’s pleasure to recently wish Father Algtie 
God-speed in his long journey and a rich measure of 
success from the results of his observations to be made in 
that far-off land. 
The Greenwich Observatory has accepted from the 
maker, Sir Howard Grubb, an equatorial with an object 
glass of twenty-eight inches aperature, and the Astronomer 
Royal reports that it is satisfactory. 
The United States Naval Observatory, one of the most 
magnificent and complete astronomical edifices in the 
SCIENGE. 
120 
world, both in instrumental equipment and offices for the 
astronomers, was during the year formally opened. 
The Dudley Observatory at Albany, N. Y., has, under 
the wise administration of its director, Professor Lewis 
Boss, been moved to a more desirable site, a new twelve- 
inch object glass by Brashear has been supplied, the other 
instruments repaired and refitted with all modern con- 
veniences, anda substantial residence built for the director 
in proximity to the instruments. 
Dr. S.C. Chandler, of Cambridge, Mass., has presented 
to the astronomical world a remarkable series of papers, 
commenced in r891, and continued through the past year. 
The exhaustive investigation undertaken by that gentle- 
man has lead to the proof that the earth’s axis of rotation 
is not invariable, but that a variation of latitude does 
exist. Dr. Chandler has made a thorough discussion of 
all astronomical observations, which bear upon the de- 
termination of latitude from the time of Bradley down to 
the present date, and anyone who has read his papers 
must be convinced that he has almost in sight the law 
that controls the variation in latitude. He has made a 
thorough discussion of the work of Struve, Peters, Gyldén 
and Nyrén at Pulkova, with both the prime vertical and 
vertical circle instruments; observations made at Wash- 
ington with the prime vertical in 1862-66; Kiistner’s 
zenith telescope work ; observations made at Cambridge, 
Leyden, Melbourne and Greenwich; Doolittle’s zenith tel- 
escope work, and Comsteck’s and Brown’s meridian circle 
observations at Madison. Allthese have been discussed 
in a masterly manner, and from them has been established 
the fact that the revolution of the earth’s pole occupies a 
period of about 427 days, moving from west to east, the 
amplitude being a variable and probably entangled with a 
yearly period. 
In connection with what has been said, the reader will 
find in WVature, vol. XLVIII., page 451, a very interesting 
paper by Professor C. L. Doolittle, given as his address 
as Vice-President of Section A (Astronomy) at the last 
meeting of the American Association for the Advance- 
ment of Science, held last summer at Madison. Professor 
Doolittle’s paper covers every historical fact connected 
with the subject of the variation of latitude, besides 
giving valuable information from the results of his zenith 
telescope observations carried on so many years at 
Bethlehem, Pa. 
Mr. S. Kostinsky, of the Pulkova Observatory, presented 
last February tothe Imperial Academy of Sciences, St. 
Petersbourg, a paper containing observations made of close 
zenith stars with the prime vertical transit instrument at 
that observatory, for the express purpose of determining 
the amplitude and period of the variation in latitude, 
recently dug up by Chandler. From that series an aplitude 
of 0.60”, with a period of 412 days, isdemonstrated. Mr. 
Kostinsky’s paper will be found in Bulletine de l’Académie 
Impériale des Sciences de St. Petersbourg, tome viu., 
page 367. 
Upon exhibition at the World’s Fair was a new form of 
pendulum devised by Sigmund Riefler, of Munich. Mr. 
Leman read a very interesting paper before the Con- 
gress of Astronomy held in Chicago, which was a descrip- 
tion of the pendulum. His paper appeared in the De- 
cember number of Astronomy and Astro-Physics. Ac- 
companying the article was a table extracted from the 
records of the Royal Observatory at Munich, giving the 
daily rate of the clock controlled byone of Mr. Riefler’s 
pendulums. ‘The period covered by the table is from Sep- 
tember 1, r891, to September 2, 1892, or one year. Dr. 
Seeliger, the Director of the Observatory, states, in for- 
warding the table, that with a variation of temperature up 
to 30° centigrade no influence worth mentioning on the 
rate of the clock could be perceived. The mean ‘daily 
