ASTRONOMY, PROGRESS OP, IN 1891. 



65 



('11 I 1 . 1 . '.M^ Tauri. .". CamclorwrdalK Nu Gemino- 

 ruin. :tti (icminonim, Tau Herculia, 84 and Psi 

 1 A(|iiurii. Seven of the li-t previously known 

 a> doiihles were found to be triples, '/'he total 

 niiiuhcr of double stars found by him is 1,224. 

 dinu r tin- ruiiilM-rin^ of our catalogues of 

 doiihlc slurs with uninteresting pairs, he says: 

 "If my purpose hud Wen to iiuike tin imposing 

 _rue of discoveries by finding as many new 

 us possible without reference to their char- 

 i he number in my lists, down to this time, 

 could easily hiivo been made many times larger 

 without exceeding the Struve limits of magni- 

 tude- and distance; but at this time there would 

 no good reason for incumbering a double- 

 bur catalogue with that kind of material. We 

 now know that they can have no interest as 

 doiihle stars in the proper sense of the term. 

 With large telescopes, pairs of 5" or 6" distance 

 in the lower magnitudes of the Durchmusterung 

 can be found by the score on any night when 

 the seeing is too poor for ordinary microraetrical 

 work, and with the 12-inch it would be easy to 

 make a large list in a comparatively short time. 

 I have not allowed myself to find new pairs of 

 the kind recorded hero any faster than they could 

 be thoroughly measured. It may be many years 

 before some of these are reobserved, and it is 

 desirable to have a careful set of measures at this 

 time with which to compare future measures." 



Speaking of the double component of Gamma 

 Andromeda, he says the elongation is doubtful 

 with powers, on the 86-inch, of 1,900 and 3,300, 

 and he thinks the distance much less than O'l". 



Mr. Burnham has, from measures of his own 

 continued from the date of discovery, ascertained 

 that the close companion to Kappa Pegasi makes 

 a revolution round the principal star in the as- 

 tonishingly short time of a little over eleven 

 years, making it the shortest-period binary visu- 

 ally known. In the monthly notices of the Roy- 

 ' al Astronomical Society for March, 1891, is given 

 a diagram of its orbit. He has derived the fol- 

 lowing elements: Major axis, 0-636" ; minor axis, 

 0-187"; maximum distance, 0'32"; minimum dis- 

 tance, 0'08" ; position angle major axis, 125-4 ; 

 period, 11 - 18 years. 



Telescopes. The number of telescopes annu- 

 ally manufactured in the United States by A Ivan 

 Clark's Sons, of Cambridgeport, Mass., and by 

 John A. Brashear, of Allegheny, Pa., besides other 

 makers of lesser note, indicates a wonderful ad- 

 vance of astronomy in this country. 



Because of the great difficulty of casting per- 

 fect disks, only one has been secured for the 40- 

 inch telescope of the Observatory of Southern 

 California, and not two, as was reported last year, 

 unless one was returned, and consequently no 

 progress has been made. 



For the Bruce Photographic telescope neither 

 disk has been received, but theClarks have near- 

 ly completed the great prism 25 inches square 

 to be attached to the front of its 24-inch ob- 

 jective. Great results are looked for by astrono- 

 mers from this instrument, which Prof. Pickering 

 calls a " photographic doublet," being only 11 

 feet focus. It is, in fact, a photographic camera. 

 " With it," he says, "a portion of the sky cover- 

 ing twenty-five square degrees can be photo- 

 graphed with good definition, while only three or 

 four degrees can be covered equally well with 



telescopes of the usual form." The time to pho- 

 tograph the entire sky, without after enlarge- 

 ment, will be reduced in the name proportion. 

 With such a doublet, each hemisphere could be 

 covered in one year with 800 plates. 



Tin- huilding for the great equatorial Comic", 

 at Paris, is completed. Instruments of this kind 

 " elbowed telescopes" are finding much favor 

 in other countries besides France. This at Paris 

 has an objective 24 inches in diameter, and two 

 plane mirrors of, respectively, 20 and 34 inches in 

 diameter. A photographic objective, also of 24 

 inches aperture, is provided, and the change from 

 one to the other can be easily and quickly made. 

 Photographs of the moon 11 inches in diameter 

 can be taken without subsequent enlargement. 



The 16'2-inch telescope for Goodsell Observa- 

 tory, Northfield, Minn., is finished, and Prof. W. 

 W. Payne, its director, speaks highly of its per- 

 formance on difficult test objects. The crown 

 disk was obtained from Mantois, of Paris, and 

 the flint from Jena, of Germany. The computa- 

 tions for the curves were made by Dr. C. S. Hast- 

 ings, of Yale University, on a new plan, and this 

 is the largest objective ever made on this formula. 

 The per cent, of merit for color correction and 

 blackness of field is 2'11, while if made of the 

 usual curves it would be but 1-61. J. A. Bra- 

 shear, of Pittsburg, ground and polished the 

 lenses, and Warner and Swasey, of Cleveland, 

 Ohio, constructed the mounting and dome. The 

 total weight of the telescope and its accessories 

 is 12,700 pounds. 



Prizes and Benefactions. Of the gift of 

 $6,000 from Miss Catharine Bruce, for the pro- 

 motion of original astronomical research, the en- 

 tire sum has been distributed by Prof. Pickering 

 in accordance with the dcnor's wishes. Among 

 the recipients were the following Americans: 

 Prof. W. W. Payne, Editor of the "Sidereal Mes- 

 senger " ; Prof. E. S. Holden, Director of the 

 Lick Observatory; Prof. Simon Newcomb, Su- 

 perintendent of the American Nautical Almanac 

 Office ; Prof. Henry A. Rowland, of Johns Hop- 

 kins University; and Prof. Lewis Swift, Director 

 of the Warner Observatory. 



The Lalande prize of the French Academy of 

 Sciences, of the value of 540 francs, has been 

 awarded to Prof. Schiaparelli, of Milan, Italy, 

 for, chiefly, his observations tending to prove the 

 synchronization of the rotational and revolution- 

 al periods of Mercury and Venus. 



The Valz prize has been adjudged to Prof. S. 

 Glasenapp, Director of the Observatory of the 

 University of St. Petersburg, Russia, for his in- 

 vestigations of the orbits of the double stars in 

 the Pulkowa Catalogue. 



Prof. C. A. Young, Director of the Halstead 

 Observatory. Princeton, N. J., has received the 

 Janssen pri/e for his speetroscopic discoveries. 



The Danish Academy of Sciences has given a 

 gold medal to Baron E. v. Ilaerdtl, of Innspruck, 

 Austria-Hungary, for his memoir on the problem 

 of three bodies, proposed by the Academy in 1889. 



The Copley medal of the Royal Society of Lon- 

 don was awarded to Prof. Simon Newcomb for 

 his contributions to gravitational astronomy. 

 Dr. Franklin .was its first recipient in 1753, and 

 it has been conferred annually ever since. 



The Donohoe comet modal, via the Astronomi- 

 cal Society of the Pacific, has been presented to 



