SCIENCE 



[N. S. Vol. XXXIX. No. ! 



enormous amount of time and money had 

 been spent. 



For many years the Kiel and Harvard 

 observatories have served as distributing 

 centers of astronomical discoveries and ob- 

 servations in Europe and America, o-e- 

 spectively. The last new star which is 

 known to have appeared, Nova Gemi- 

 norum, No. 2, was discovered by Enebo at 

 Dombass, Norway, on Tuesday, March 13, 

 1912. The cable message was received at 

 Cambridge Wednesday morning, and the 

 star was observed at several American ob- 

 servatories the next evening, or the night 

 following its discovery. An examination 

 of the Harvard photographs showed that 

 two plates had been taken on the preced- 

 ing Sunday, March 11, on which no trace 

 of the Nova was visible, and two on Mon- 

 day, March 12, showing it of nearly its full 

 brightness. Photographs taken Wednes- 

 day compared with those obtained a few 

 days later showed the wonderful change 

 in its spectrum, from the solar type with 

 dark lines, to the typical spectrum of a 

 Nova with bright lines. 



There is no department of astronomy 

 which is now receiving greater attention 

 than the study of the spectra of the stars. 

 Dr. Henry Draper was the first to photo- 

 graph the lines in a stellar spectrum, al- 

 though Sir Williams Huggins had already 

 obtained a mark from the spectrum of 

 Sirius, and later was the first to publish 

 his results in successfully photographing 

 stellar • spectra. The untimely death of 

 Dr. Draper, in the midst of Ms work, led 

 to the establishment at Harvard of the 

 Henry Draper Memorial. For nearly 

 thirty years Mrs. Draper has maintained 

 an active interest in this work. By placing 

 a large prism over the objective of a tele- 

 scope, the light of all the brighter stars in 

 the field are spread out into spectra, so that 

 instead of photographing the spectrum of 



one star at a time, as with a slit spectro- 

 scope, as many as a thousand have some- 

 times been taken on a single plate. Such 

 photographs, covering the entire sky, have 

 been taken with the two 8-ineh doublets 

 already mentioned. A study of the spec- 

 tra thus obtained enabled Mrs. Fleming to 

 discover many hundred objects whose 

 spectra are peculiar. Among them may be 

 mentioned 10 of the 19 new stars known 

 to have appeared during the years in which 

 she was engaged in this work, while five of 

 the others were also found at Harvard by 

 other observers. She discovered more than 

 two hundred variable stars, 91 out of the 

 108 stars of the very peculiar fifth type, 

 and showed that these objects occurred 

 only very near the central line of the 

 Milky Way. During the last two or three 

 years a great demand has arisen for the 

 class of spectrum of large numbers of 

 stars. The Harvard photographs show the 

 class of spectrum of nearly two hundred 

 thousand stars. Miss Cannon has, accord- 

 ingly, undertaken to prepare a catalogue 

 of these objects, with the result that she 

 has already classified about one hundred 

 and fifteen thousand spectra, covering 

 more than one half of the sky. The work 

 is progressing at the rate of five thousand 

 stars monthly, and the results wiU fill 

 seven of the large quarto Annals of the 

 Harvard Observatory. The organization 

 of this work has required the most careful 

 application of the principles of "scientific 

 management. ' ' 



One of the most important results de- 

 rived from the Harvard photographs was 

 the discovery that in certain spectra the 

 lines were alternately double and single. 

 This, and the discovery by Vogel at Pots- 

 dam that the lines of the variable star Algol 

 continually changed their position re- 

 vealed the existence of spectroscopic bi- 

 naries. No department of astronomy is 



