ASTRONOMY. 49 



periment of converting the entire Equatorial into a large spectro- 

 scope. The eye-piece end will be pointed to the sun and furnished 

 with a slit and a prism of total reflection for the diffracted rays, the 

 telescope constituting a collimator of great focal length, and being 

 used also, at the same time, as observing telescope for the spectrum, 

 from a large grating attached to and moving with it. Preparations 

 have been made for applying photography to the study of problems 

 connected with the sun, and this department, which has been en- 

 forcedly neglected, will soon, it is hoped, be in operation. 



5th. A popular account of " The Electric Time-service " appeared 

 in the April number of Harper's Monthly for 1878. 



An article on the " Transit of Mercury " was contributed to the 

 American Journal of Science and Arts, vol. xv., June, 1878, and an- 

 other on the same subject to the Monthly Notices of the R. A. S. for 

 June, 1878. 



Memoirs describing the principal scientific work of the year are 

 shortly to appear, but are not yet printed. 



Brooklyn, N. Y. : Private Observatory of Henry M. Parkliurst. 



This consists of a two-story brick building, with revolving roof 

 opening on both sides. The Telescope is nine inches clear aperture, 

 by Henry G. Fitz, mounted equatorially, with circles reading to 

 minutes of space. It has been employed, during the few months of 

 the year when it could be employed otherwise than in miscellaneous 

 observation, in continuing an investigation of the law of the visi- 

 bility of stars under illumination, chiefly by observations during the 

 day and in the twilight. 



Buffalo, X. Y. : Private Observatory of Henry Mills, Esq. 



My principal instrument is a Telescope of 3-inch object-glass and 

 44-inch focus, which I use chiefly for the entertainment of my friends 

 in viewing such celestial objects as come within range of such an in- 

 strument. 



Besides a report made to the Naval Observatory on the transit of 

 Mercury on May 5 and G, I have no special work to record. 



Cambridge, Mass. : Harvard College Observatory. 



Professor E. C. Pickering, Director. 

 1st. The observers and computers at present constantly employed 

 at the observatory building are : 



Edward C. Pickering, S.B., Phillips Professor of Astronomy and 

 Director of the Observatory. 



William A. Rogers, A.M., Assistant Professor of Astronomy. 



C 



