CERTAIN ASPECTS OF RECENT SPECTROSCOPIC OB- 

 SERVATIONS OF THE GASEOUS NEBULA WHICH 

 APPEAR TO ESTABLISH A RELATIONSHIP 

 BETWEEN THEM AND THE STARS. 



By W. H. WRIGHT. 

 (Read April 24, 1920.) 



The Lick Observatory has carried on during recent years a 

 number of researches on the nebulae. About two years ago these 

 had taken a form sufficiently substantial to serve as the basis of a 

 publication, and a number of memoirs entitled Studies of the Nebulce 

 were prepared at that time. Owing to industrial conditions de- 

 veloped by the war the printing of these papers was greatly delayed, 

 and they have only now been issued as Volume XIII. of the Pub- 

 lications of the Lick Observatory. As one of the contributors to 

 that work I have been asked to present some account of the in- 

 vestigation with which I am particularly concerned. It may be 

 said that my own observtions are spectroscopic, and are confined 

 to the gaseous nebulae. 



In attempting to give a comprehensive account of a survey in a 

 relatively new field one is likely to be embarrassed by the hetero- 

 geneity of the material that presents itself for description. Astro- 

 physics is essentially such a new field, and it is sometimes difficult 

 to wander very far from what we consider, perhaps too confidently, 

 the well-worked border without being overwhelmed with a diversity 

 of new, and totally unexpected facts, which frequently serve to 

 control the path of progress. Whatever was the original purpose 

 of the quest, it is likely to have become modified by factors of its 

 own development in such a way that the accumulated information 

 bears apparently on a number of problems, and offers a complete 

 solution of none of them. At any rate that has, in a sense, been the 

 course of the present investigation. It had its beginnings in an at- 



517 



PROC. AMER. PHIL. SOC, VOL. LIX, GG, DECEMBER 30, I92O 



