142 



Sir Norman Lockyer. 



that the pelvic girdle in different specimens is not homologous — an 

 assumption which at present seems unjustifiable. 



(3) The different variations observed are not discordant with the 

 view that the limb is capable of migrating along the body, on which 

 view it must be supposed that a secondary rostral migration has 

 followed a primary caudal one. Moreover, such a view receives 

 confirmation from the existence of a posterior collector and of a more 

 extensive anterior collector in certain embryonic stages. 



"Further Observations on Nova Persei." By Sir Norman 

 Lockyer, K.C.B., F.B.S. Beceived and Bead March 7, 1901. 



[Plate 1 .] 



Since the preliminary note on this star was communicated to the 

 Boyal Society on February 28th, observations have been possible on 

 the nights of February 28th, March 1st, 3rd, and 5th, and twenty- 

 four photographs of the spectrum have been taken with the instru- 

 ments before detailed. 



It may be stated generally that the light is slowly waning. On 

 February 28 th the star was only slightly brighter than a Persei. On 

 March 1st it was estimated as about equal to a Persei, i.e., about 2*0 

 magnitude. When it was again visible on the evening of March 3rd, 

 it was distinctly less bright than f3 Persei, and its magnitude probably 

 near 2*5 ; on the 5th its estimated magnitude was 2*7. 



The above refers to the visual brightness. A photograph of the 

 region occupied by the Nova on March 3rd showed it to be photo- 

 graphically brighter than oc Persei. 



General Description of the Spectrum. 



The photographs show that the bright hydrogen lines are succes- 

 sively feebler as the ultra-violet is approached, and the whole of the 

 series of hydrogen lines have during the past week become relatively 

 brighter with respect to the remaining lines and the continuous 

 .spectrum. The spectrum extends far into the ultra-violet. 



Among the changes which have taken place in the visible part of 

 the spectrum, it may be mentioned that while the lines of hydrogen 

 have become relatively brighter during the past week, the remaining 

 lines, with the possible exception of the prominent one at A 5169, have 

 become distinctly dimmer. There has also been a diminution of the 

 intensity^ of the continuous spectrum. The line in the yellow, the 

 identity of which has not yet been definitely determined, has gradually 

 decreased in intensity with the diminution of brightness of the star. 



