128 RECORD OF SCIENCE FOR lb87 AND 1888. 



the definitiou was good in a ceutral circular area about 7 degrees in 

 diameter. Fourteen of the objects pbotograpbed are contained in 

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

 that are pbotograpbed are not in tbe catalogue. Professor Pickering 

 concludes tbat in carrying out tbe same proportion we might expect 

 to discover four or five thousand such objects by photographing the 

 whole sky; but, he adds, ''there is one consideration that may seriously 

 modify this conclusion. The successive improvements in photography 

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

 plates show that it not only includes the sword-handle, c, z, and 0, but 

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

 others, both north and south, indicate that perhaps the next i-ncrease 

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

 degrees in length." 



Herr von Gothard has obtained extraordinary results with a 10-inch 

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

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

 2854 of the Nachrichten. The photographs of clusters Dr. Vogel was 

 able to enlarge without great difficult^', but for thenebulteit was neces- 

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

 photograph of the spiral nebula in Canes Venatici is particularly inter- 

 esting. 



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

 the nebuljB examined with the 36 inch Lick telescope show a multitude 

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

 Lassell's 4-foot reflector and the Washington 26inch refractor show 

 thirteen stars in an oval outside the ring, and only one star Avithin it, 

 while the Lick glass shows twelve stars within the ring or projected on 

 it, and renders it obvious that the nebula consists of a series of ovals 

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

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

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

 losity and outer oval. 



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

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



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

 land has observed a new line apparently identical with 1^3, wave-length 

 587.4. The occurrence of this line in the spectrum of a nebula is of 

 great interest as aflbrding another connecting link between gaseous 

 nebula? and the sun and stars with bright-line spectra, especially with 

 that remarkable class of stars, of which the first examples were de- 

 tected by Wolf and liayet in the constellation Cygnus. 



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

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

 principal stars in the Pleiades as determined with the new Yale heliom- 

 eter, and it is, we believe, the first heliometer work done in this couu- 



