G30 REPORTS OF ASTRONOMICAL OBSERVATORIES. 



Mrs. Anna Winlock, 

 Mrs. R. T. EoGERS, 

 W. Y. Brown, 



A. W. Cutler, 



J. Eayner Edmunds, 



B. PiCKMANN Mann, 

 William A. Eogees, 

 Arthur Searle, 

 Frank Waldo, 



O. 0. Wendell. 

 Annexed to Harvard College; projected in 181C; ground acquired in 

 1827 ; instruments set up in 1839; a central structure, with a great dome, 

 two wings, two pavilions, surmounted by domes at the extremities of 

 the wings. Here it was that G. P. Bond discovered in 1848 the seventh 

 satellite of Saturn {Hyperion), and in 1850 the dusky interior ring inside 

 the bright rings of that planet. This observatory possesses one of W. 

 C. Bond's chronographs, mounted in 1849, and an equatorial of 2G^ 

 inches (0°i.68) aperture. 



iNSTRUilENTS : 



{«) Meridian circle: makers, Troughton & Simms (glasses by Alvan 

 Clark «& Sons); diameter of circles, 36 inches; divided to 5'; each cir- 

 cle read by 4 microscopes to 0".l; aperture of objective, 8^ inches: 

 for observations of the sun, aperture emj)loyed, 8^ inches; magnifying 

 power ordinarily employed, 300 to 350 diameters, {a') East transit cir- 

 cle, by Troughton & Slmms; diameter of circles, 48 inches; divided to 

 5'; each circle read by 4 microscopes to 0".2; aperture of objective, 

 4| inches. 



(&) Meridian trafisit instruments: one made by Herbst, of Pulkowa,* 

 aperture, 2| inches ; magnifying power, up to 200 diameters, (b') Large 

 photometer, mounted in the meridian, for comparing images of stars 

 during transit. 



(c) Equatorial instruments : one made by Merz ; aperture of objective, 

 15 inches ; magnifying powers of eye-pieces, 100 to 2000. (c') West equa- 

 torial, by Alvan Clark & Sons ; aperture, 5^ inches. 



{d) Spectroscopes: three, described in vol. viii of the Annals of the 

 Observatory. 



(e) Photometers and other suhsidiary apparatus : One Zollner photo- 

 meter, and several photometers of other kinds. 



(/) Chronographs : two, spring governors, by W. Bond & Son; one 

 small barrel chronograph. 



{g) Cloclis: one mean time; maker. Bond, 394: one sidereal; makers, 

 Frodsham, 1327; Bond, 312. 



(/i) Chronometers: two sidereal; makers, Frodsham, 3451; Bond, 

 23G; one thermometric chronometer, Frodsham, 3424. 



(i) Miscellaneous : Comet-seeker and other small telescopes and appa- 

 ratus. 



