Webb. — On Astronomy ancl Celestial Physics. Iv 



This splendid aurora was coincident with a period of equally notable 

 agitation of the surface of the sun. Sign or Tacchini, the Director of the 

 Observatory at Palermo, who devotes himself with great ardour to the spec- 

 troscopic observation of the sun, thus describes the condition of things which 

 he found prevailing when the sun rose on the morning of the 5th : — " All the 

 surface of the sun was in abnormal circumstances ; the entire rim was 

 covered with splendid flames ; towards the North Pole these rose to the 

 height of 20"'' (equal to about 9,000 miles), over an arc of 36° to the 

 right and to the left, corresponding to a region of (incandescent) magne- 

 sium which on the western border extended to the Equator. In this 

 region, at 50° from the pole, a magnificent protuberance was observed 

 which rose to a height of 2' W^ (more than 70,000 miles), and from this 

 point through an arc of 40° the rim presented numerous brilliant flames, 

 and the atmosphere was completely encumbered with luminous threads and 

 shining points up to a height of 2' (55,000 miles). The chromosphere was 

 throughout more elevated than usual." Along with this agitation of the 

 surface of the sun was to be noted the striking brilliance of the zodiacal light, 

 which some physicists are now maintaining to be in fact a solar aurora. 

 Intimately connected with the auroral display was the appearance of a group 

 of meteors, the radial point of which was in an unusual position. As usual 

 on such occasions a magnetic storm prevailed, and the various telegraph lines 

 including the Atlantic cable were taken possession of by induced currents, 

 which for a considerable period rendered it impossible to work them. 



The unusual climatic conditions, and the exceptional prevalence and 

 intensity of auroras (that of 4th February was only the most conspicuous 

 of an extensive series), have filled the transactions of scientific societies and 

 the pages of periodicals devoted to science with statistics, arguments, and 

 theories, all having for their object the elucidation of the cosmical origin of 

 those terrestrial phenomena, I purposed to have given a general account of 

 these to-night, but time will not permit. The intimate connection between 

 both these classes of phenomena and the condition of the surface of the sun is, 

 of course, a fundamental feature with all of them. Signer Tacchini gives it as 

 his opinion that " our polar auroras are nothing else, at least in the majority 

 of cases, than phenomena of electric induction due to the immense auroras 

 produced on the sun." In one form or another this is admitted by almost all 

 theorists on the subject. One theorist has with much ingenuity attempted to 

 connect these phenomena with one another, not as cause and effect, but as 

 both resulting from a common cause. M. Silbermann, after a life-long study 

 of atmospheric currents, forms of clouds, shooting-stars, auroras, and solar 

 phenomena, has reached the conclusion that the innumerable streams of 

 meteors which the earth is continually passing through, are the efficient causes 



