206 Mr. J. N. Lockyer. On the Classification [Jan. 10, 



Comet of 1882. At perihelion, this comet was only 300,000 miles 

 from the photosphere of the sun, and it was practically as bright as 

 the sun itself. Mr. Finlay, at the Cape, followed the comet until it 

 apparently rushed into the sun. That a comet should be able to pass 

 within so short a distance of the sun without suffering entire dis- 

 ruption has been used as an argument against the existence of an 

 extended solar corona. My own view of the case, however, is that 

 the evidence afforded by this comet of the existence of a meteoritic 

 solar atmosphere is most conclusive. 



That it would be impossible for a comet to pass through a gaseous 

 atmosphere is proved by our terrestrial experience with falling stars, 

 but if the regions far above the sun's photosphere are constituted as 

 I have suggested,* we should expect a transcendental clashing effect, 

 but no change in the orbits of the meteorites which were not 

 engaged. 



I would submit, therefore, that the immediate cause of the 

 enormous increase in brilliancy of the comet, which enabled it to be 

 obtained close to the sun's disk, was undoubtedly the collisions which 

 took place between the meteorites constituting the comet, and those 

 which occupy the outer cooler regions of the sun. Not only does 

 this event demonstrate the existence of an outer solar atmosphere, 

 therefore, but it also points to its meteoric nature, the meteo- 

 rites there being probably formed by the condensation of metallic 

 and other vapours, exactly in the same way as we have snow and 

 raindrops in our own atmosphere. Observations by Messrs. Finlay 

 and Elkins before and after perihelion showed that the comet was 

 not perceptibly retarded by its adventure, which is quite consistent 

 with my view, collisions between individual meteorites would not 

 retard the motion of the comet as a whole. 



Another case of considerable interest is the Pons-Brooks Comet, 

 1883 1884. At its last return this comet was first observed by 

 Mr. Brooks on September 1, 1883; it passed perihelion on January 

 25th, and was last seen on June 2nd, 1884. It was distinguished by 

 its sudden fluctuations in brilliancy, which no doubt were caused by 

 its intersection with other swarms. On September 21st, it was 

 observed by Mr. Chandler, at Harvard,f as a faint nebulosity with a 

 slight condensation. On the 22nd, it was represented by an apparent 

 star of the eighth magnitude, according to the observations of 

 Schiaparelli,J the luminosity having been augmented eight times 

 within a few hours. 



In a short time, the comet again appeared as a nebulous disk. This 

 sudden change has an exact parallel in " new stars," and the cause is 



* ' Boj. Soc. Proc.,' vol. 40, p. 357. 

 f 'Astr. Nachr.,' No. 2553. 

 I ' Astr. Nachr.,' No. 2553. 



