REPORTS OF ASTRONOMICAL OBSERVATORIES. 003 



zenith telescope by Blunt, and a prismatic sextant by PiSToii & Mar- 

 tin. 



Observations duiiing tue past year : 

 Besides the work of instruction, the principal work of the Observatory 

 has been a series of measnreiuents of position angles and distances of 

 Jupiter's satellites, and of their eclipses. 



Work proposed for the co3iing year (18S1) : 

 Observations of Jupiter will be kept up, with such attention to comets 

 as circumstances will permit. 



South Hadley, Massachusetts. 

 Observatory at Mount Rolyolce Seminary. 



Longitude from Washington, ? 



Latitude, ! 



Through the liberality of Mr. A. L. Williston, of Xorthampton, the 

 seminary has recently been enabled to erect a small but very comjilete 

 astronomical Observatory, supplied with all the necessary instruments. 

 It is designed to furnish the means for instruction to any who may wish 

 to make the subject a specialty, and to give oi)portunity to any of the 

 teachers or i)ost-gTaduates who may take an interest in astronomy to 

 make observations of real value. 



The building, of wood, consists of a tower with a dome 18 feet in 

 diameter, flanked by two wings, one extending to the east and one to 

 the north. The dome is very light, and rotates so easily that even the 

 feeblest of the young ladies can manage it without difdculty. The ar- 

 rangements for opening and closing the shutters which cover the slit in 

 the dome, and the openings for the transit and prime vertical instrument, 

 are worked with equal facility. In the dome is mounted a fine 8-inch 

 equatorial by Clark, completely fitted out with clock-work, finding- 

 clock, micrometers, spectroscope, solar eye-piece, &c., and so arranged 

 that the circles can be read and the clamps and tangent screws worked 

 from the eye-piece of the instrument. 



The object-glass is almost entirely the work of the senior Alvan 

 Clark, and is one of the most perfect specimens of his art. 



In the transit-room is mounted a meridian circle by Fauth & Co., of 

 Washington. The instrument has a telescope of 3 inches aperture, and 

 circles of IG inches diameter, reading to seconds by two microscopes. 

 It has a reversing apparatus, and is fitted with a "latitude level" and 

 micrometer, so that it can, if desired, be used as a zenitli telescope. A 

 large collimator is mounted upon a pier south of it, and in a corner of 

 the room is a clock with Denison escapement, also by Fautii & Co., as 

 is the chronograph, which is mounted in an adjoining closet. The Ob- 

 ervatory possesses also a sextant and artificial horizon and a set of 

 smeteorological apparatus. 



