128 EECORD OF (SCIENCE FOR lfe87 AND 1888. 



tbe definition was good in a central circnlar area about 7 degrees ia 

 diameter. Fourteen of the objects pliotograpbed are contained in 

 Dreyer's catalogue; four in tbe catalogue are not pbotograpbed; twelve 

 tbat are pbotograpbed are not in tbe catalogue. Professor Pickering 

 concludes tbat in carrying out tbe same proportion we migbt expect 

 to discover four or five thousand sucb objects by i)botograpbing tbe 

 wbole sky; but, be adds, ''tbere is one consideration tbat may seriously 

 modify tbis conclusion. Tbe successive improvements in photography 

 have continually increased tbe limits of tbe nebula in Orion. These 

 plates show tbat it not only includes tbe sword-handle, c, /, and ^/, but 

 a long nebulosity extends south from C, others surround tbis star, while 

 others, botb north and south, indicate that perbaps the next increase 

 in sensitiveness of our plates will join them all in a vast nebula many 

 degrees in length." 



Herr von Gotbard has obtained extraordinary results witb a 10-incli 

 reflector. His photographs, though small, show a great richness of de- 

 tail; several of them arc reproduced in an article by Dr. Vogel, in No. 

 2854 of tbe Nacbricbten. Tbe photographs of clusters Dr. Vogel was 

 able to enlarge without great difficulty, but for the nebulae it was neces- 

 sary to resort to drawings; among the latter tbe reproduction of a 

 l)botograpb of tbe spiral nebula in Canes Venatici is particularly inter- 

 esting. 



The Ring Nebula in Lyra. — Professor Holden reports tbat nearly all 

 tbe nebuli3B examined witb tbe 30 inch Lick telescope show a multitude 

 of new details of structure. In the King Nebula in Lyra, for example, 

 Lassell's 4 foot retlector and tbe Washington 26 inch refractor show 

 thirteen stars in an oval outside tbe ring, and only one star within it, 

 wbile tbe Lick glass shows twelve stars within the ring or projected on 

 it, and renders it obvious tbat tbe nebula consists of a series of ovals 

 or ellipses — first tbe ring of stars, then the outer and inner edges of tbe 

 nebulosity; next a ring of taint stars round tbe edges of the inner ring, 

 and last a number of stars situated on tbe various parts of tbe nebu- 

 losity and outer oval. 



Mr. lioberts' photographs of the Eing Nebula in Lyra, tbe Great 

 Nebula in Andromeda, and others, also require special mention. 



The Great Nehula in Orion. — In the spectrum of this nebula, Dr. Cope- 

 land has observed a new line apparently identical with D3, wave-length 

 587.4. Tiie occurrence of tbis line in tbe spectrum of a nebula is of 

 great interest as affording another connecting link between gaseous 

 nebulfc and tbe sun and stars witb bright-line spectra, especially witb 

 tbat remarkable class of stars, of which tbe first examples were de- 

 tected by Wolf and Kayet in tbe constellation Cygnus. 



The Pleiades. — The initial volume of publications of tbe Yale Observa- 

 tory is a valuable memoir by Dr. W. L. Elkin on tbe positions of tbe 

 principal stars in tbe Pleiades as determined witb tbe new Yale beliom- 

 eter, and it is, we believe, tbe first beliometer work done in this c(mn- 



