278 SCIENTIFIC RECORD FOR 1862. 



of the parts, but that no evidence exists of any changes of form other 

 than those which might be due to changes iu relative brightness. 

 These changes in brightness have been examined by the author by 

 photouietric measures by means of an instrument devised by Prof, 

 diaries S. Hastings. 



An addendum gives a magniScent photograph of the nebula made by 

 Dr. Henry Draper, his last published work. The frontispiece is Bond's 

 beautiful steel engraving of the nebula, which was kindly furnished by 

 Professor Pickering; 



Spectrum of Nebula i)i Orion. — Dr. Huggins has succeeded in photo- 

 graphing the spectrum of the nebula of Orion (March 7, 1882,), and "in 

 addition to known lines" a strong line in the ultra-violet is shown. The 

 same thing had also been done by Dr. Henry Draper, and from a private 

 letter we learn that he had made four such iihotographs, which show 

 that two knots of nebulosity in the bright mass just preceding the 

 trapezium have a continuous spectrum, and that there are traces of the 

 same in other parts of the nebula. 



Dr. Huggins has obtained a fine photograph of the spectrum of this 

 nebula, which shows a ncic line X 3730, in addition to the four which he 

 has located iu the visible spectrum. 



In this connection it may be worth while to correct a common, al- 

 though a natural, error with regard to the question of the discovery of 

 the discontinuous nature of the spectra of nebulse. 



In August, 18G4, Dr. Huggins investigated the spectra of nebulre be- 

 fore any other observer, and communicated the results to the Roj^al 

 Society on September 8, 1^64. 



Secchi's observations of the spectra of n^bulre are published in the 

 Comptcs liendus of 180."), and api^ear to be the record of an indei)endent 

 discovery 5 ceitainly they are usually so considered. That they are 

 not independent, may be seen from the fact that the results of Dr. Hug- 

 gins were communicated to P. Secchi by Director Otto V. Struve, who 

 was at the time on a mission to Rome. Secchi received the announce- 

 ment with incredulity, but as Struve insisted on its correctness Secchi 

 pointed on a nebula and saw the gaseous spectrum for the first time in 

 consequence of this announcement. This may not seem important now, 

 but it is a portion of the history of astronomy, and if recorded at all, 

 it should be stated correctly. 



FIXED STARS. 



Dr. GoukVs southern zones. — The second volume of the Cordoba ob- 

 servations is at last printed. (Vol. I was the Uranometria Argentina.) 

 It contains the places of some 400 southern stars for the large catalogue 

 of 30,000 southern stars, and also 128 zones, containing some 13,000 

 stars. This is the first installment of a very important work under- 

 taken by Dr. Gould in 1870-'71 ; which was to prepare a zone catalogue 

 of the region of the sky from (and overlapping) Argelander's southern 



