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POPULAR SCIENCE MONTHLY. 



seems to have a special actinic power, as the star is more conspicuous 

 on the photographs than to the eye. 



There are several other annular nebulas which are fainter than 

 than of Lyra. The one best visible in our latitudes is known as 

 H IV. 13, or 4,565 of Dreyer's catalogue. It is situated in the con- 

 stellation Cygnus which adjoins Lyra. Both Herschel and Lord Eosse 

 have made drawings of it. It was photographed by Keeler with the 



Fig. 14. Nebulous Mass in Cygntjs, including H. V. 14 and H. 2093. 

 Photographed at the Lick Observatory. 



Crossley reflector on the nights of August 9 and 10, 1899, with expo- 

 sures of one and two hours, respectively. Keeler states that the nebula, 

 as shown by these photographs, "is an elliptical, nearly circular ring, 

 not quite regular in outline, pretty sharply defined at the outer edge." 

 The outside dimensions arc: 



Major axis 42". 5 



Minor axis 40 .5 



Position angle of major axis 32° 



