126 



Sir Norman Lockyer. 



"The Piscian Stars." By Sir E'orman Lockyer, KC.B., F.E.S. 

 Eeceived November 20, — Eead December 14, 1899. 



Introductory. 



In the Bakerian Lecture for 1888* I briefly considered the relation 

 of the stars ha\dng spectra with predominant carbon absorption (for 

 which I have recently suggested the name Piscianj) to the various 

 other types of celestial bodies. Shortly afterwards I began the dis- 

 cussion of the observations which had been made by Duner in the case 

 of these stars. Those relating to Group II (now named Antarian), 

 another group studied by Duner, were fully dealt with in the Bakerian 

 Lecture, but after all the available information as to the former had 

 been brought together, I found that notwithstanding the admirable 

 data which Duner had put on record, there were some points on which 

 further information was desirable. 



In the Antarian stars we had evidence as to the lines present in 

 company with the various flutings, but in the Piscian stars even the 

 presence or absence of lines was somewhat uncertain. 



The publication of this investigation was therefore postponed to see 

 what light could be thrown upon the subject by further observations. 

 At various times, as the work permitted, such observations have been 

 attempted, and the results, so far as they went, did not disturb the 

 classification at which I had already arrived. Still, the information 

 thus gained was less complete than desired. 



The photographic work which has quite recently been done on these 

 stars by Dr. INIcClean and Professor Hale has now furnished the 

 additional information required, and it is therefore unnecessary to 

 delay the publication of the memoir, some ten years old, which in the 

 main points stands as it was written. 



Historical Statement. 



Secchi was the first to recognise stars with spectra of the type 

 under discussion during his spectroscopic survey made in 1866 and 

 1867. They constituted his fourth type. All the stars pi the group 

 are of small magnitude, and of a deep red colour. He was inclined to 

 believe that a radiation spectrum was in question, but pointed out that 

 there was a relation between the flutings of carbon and the dark bands 

 seen in the spectra of the stars. He says : — " Quelques-unes des raies 

 noires, et les plus importantes, coincident a tres-peu pres avec celles du 

 troisieme type ; cependant le spectre, dans son ensemble, se presente 



* *Eoy. Sec. Proc.,' vol. U, p. 26. 



t ' Roy. Soc. Proc' (1899), toI. 65, p. 191. 



