354 Sir Norman Lockyer. 



II. " The Specific Volumes of Oxygen and Nitrogen Vapour at the 

 Boiling Point of Oxygen," By Professor J. DEWAR, F.R.S. 



III. " The Distribution of Magnetism as affected by Induced Currents 

 in an Iron Cylinder when rotated in a Magnetic Field." By 

 Professor ERNEST WILSON. Communicated by Sir WILLIAM 

 PREECE, K.C.B., F.R.S. 



" The Chemical Origins of the Lines in Nova Persei." By Sir 

 NORMAN LOCKYER, K.C.B., F.R.S. Received December 23, 

 1901, Read January 30, 1002. 



In the first two papers* which I communicated to the Royal Society 

 on the observations of Nova Persei at Kensington, a general descrip- 

 tion of the spectrum in its earliest stages was given, and also a state- 

 ment as to the probable origins of some of the strongest lines, 

 depending upon a comparison of the Nova Spectrum with those of 

 a Cygni, a Canis Majoris. 7 Orionis, &c. 



A table showing the results of the detailed reduction and discussion 

 of the bright lines in the best spectrum typical of the Nova in this 

 early stage (that obtained with the G-inch objective prism on February 

 25, when the star was nearly as bright as Capella), was undertaken 

 later for inclusion in a general summary of the observations in course 

 of preparation. 



As various conclusions as to the chemical origin of some of the Nova 

 lines have recently been published which differ widely from those 

 arrived at from a careful study of the Kensington photographs, I think 

 it desirable to publish the above-mentioned table at once. A detailed 

 statement of the evidence on which these conclusions as to origin are 

 based, will follow in the general summary before referred to. 



That many of the stronger lines in the early spectra of Nova 

 Aurigse were chromospheric, has been pointed out by several observers, 

 and all agree that there is little difference in the general aspect of the 

 spectrum of Nova Aurigse arid that of Nova Persei at a correspond- 

 ing stage of development. In confirmation of this it may be said that 

 by means of direct comparison of the various Kensington photographs, 

 the identity of most of the strong bright Nova bands with lines of 

 a Cygni and the chromosphere already known to be due to enhanced 

 lines of certain metals has been established. 



With regard to the stellar relations of the Nova, I may state that in 

 my note of February 28, t the agreement in position of its lines with 



* ' Roy. Soc. Proc.,' vol. 68, p. 119 and p. 142. 

 t ' Hoy. Soc. Proc.,' vol. 68, p. 121. 



