40 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



Dr. Henry Draper's Observatory, Hastings-on-Hudson, N. Y. 



Dr. Henry Draper, Director. 



In answer to your letter of inquiry in regard to my observatory 

 at Hastings-on-IIudson 1st. My "wife is my assistant. 2d. The prin- 

 cipal instruments are a Sikercd-glass lleflector, of 28 inches aperture, 

 mounted equatorially ; an Alvan Clark Refractor, of 12 inches 

 aperture, mounted equatorially; a 15^-inch Silvered-glass liefiector, 

 mounted as an alt -azimuth; a 2 -inch Transit Instrument; Clock; 

 Chronometer ; and Chronograph. 3d. My principal work during the 

 past year has been spectroscopic photography, which has led me to 

 the discovery of oxygen in the sun. 4th. The same line of work 

 will be pursued during the coming year, as the observatory is fitted 

 with a complete electric apparatus for spectrum photography, con- 

 sisting of an engine, Gramme machine, 18-inch RuhmkorfF coil, etc. 



I have published in Silliman' > s Journal the results of an exam- 

 ination of the astronomical conditions of the atmosphere of the 

 Rocky Mountains, made during the past summer. On the whole, 

 the conclusions are that the steadiness of the telescopic images is 

 less than at New York, while the transparency of the air is much 

 greater at the higher elevations. 



Observatory of Yale College, New Haven, Conn. 



Professor C. A. Lyman, Director. 



This observatory is intended chiefly for use as a means of in- 

 struction in connection with the classes in astronomy taught in the 

 college. There is no endowment for other purposes. During the 

 past year it has been in charge of Mr. H. A. Hazen and Mr. Wm. 

 Beebe. 



Instruments. Equatorial, 8f inches; Altitude and Azimuth Instru- 

 ment^ inches; besides smaller instruments; two Sidereal Clocks and 

 ;t Sidereal Chronometer ; Sextants, etc. 



A full scries of observations on comets u, c, and/, and a few on 

 e, have been made, and partially published. 



Princeton College Observatory, Princeton, N. J. 



l'rofessor C. A. Young, Director. 



The Ilalstead Observatory, with its magnificent dome (nearly forty 

 feet in diameter), does not at present possess an instrument; but it 

 i-> hoped that within a short time the deficiency will be supplied. 



A small observatory, for purposes of instruction, is just completed 

 after tin- plan- of Professor Young, the funds being supplied for its 



