378 Mr. B. C. Brodie on the Chemical Nature 



height. The appearance could no longer be compared to 

 that of a fan but to that of a dome of fire ; the unillumined 

 portion of the horizon became confined to about one-fourth 

 part of the circle, extending more or less between S.S.W. 

 and E. : y Pegasi became enveloped in the light which shot 

 southwards from the summit, passing several degrees below 

 Saturn, so that in the S.E. not more than a space of about 30° 

 in altitude remained dark, while all the rest of the heavens 

 seemed on fire. The summit of the dome presented several 

 remarkable changes of appearance: at one time the rays met 

 as at a point, with great regularity; at another there were seen 

 great irregular masses of light gathered round it, and at an- 

 other there was a distinct circle round the centre, which was 

 dark. As the evening advanced, this crown changed its posi- 

 tion among the stars to a considerable extent, retaining how- 

 ever the same altitude and azimuth as the stars moved west- 

 ward. After 9 h 30 m p.m. the grandeur of the scene diminished, 

 and at 10 h 30 m p.m. the crimson colour had disappeared ; still 

 the streamers continued with great vigour till October 19, at 

 l h 30 m a.m., at which time the observations were discontinued. 



The altitude and azimuth of the corona were determined 

 from the spherical triangle 

 S P Y, in which S Prepre- /"""SJ Y P = 36° 10' 



sents the north-polar di- / A p S P = 61 46 



stance, and S P Y the hour- /s^~ SPY=15 



angle of a Andromedae at g 

 9 h P.M. 



From this the zenith distance of the corona appears to have 

 been about 18° south, and its azimuth to have been about 41° 

 east. 



On the 19th and 20th there were also slight exhibitions of 

 aurora borealis. On these days the magnets at Greenwich 

 Observatory were affected, as I learn both from Mr. Glaisher 

 and from the Registrar- General's Report for the week ending 

 October 21st 



LIX. On the Chemical Nature of a Wax from China. 

 By Benjamin Collins Brodie, Esq.* 



THE wax which is the subject of the following investigation, 

 is a substance which was imported into this country from 

 China as an article of commerce. Its appearance closely re- 

 sembles that of spermaceti. It is, like spermaceti, white and, 

 in large masses, highly crystalline, but differs from it by being 



* From the Philosophical Transactions, part i.; having been received by 

 the Royal Society March 30, and read May 11, 1848. 



