306 Anniversary Meeting. [Nov. 30, 



analysis to believe that magnetic force of the sun is directly percep- 

 tible here on the earth, we are quite certain that this steady force is 

 vastly less in amount than the abruptly varying force which, from 

 the time of my ancestor in the Presidential Chair, Sir Edward Sabine's, 

 discovery,* forty years ago, of an apparent connexion between sun- 

 spots and terrestrial magnetic storms, we have been almost compelled 

 to attribute to disturbing action of some kind at the sun's surface. 



As one of the first evidences of this belief, I may quote the follow- 

 ing remarkable sentences from Lord Armstrong's Presidential 

 Address to the British Association at Newcastle, in 1863 : 



" The sympathy also which appears to exist between forces operat- 

 ing in the sun and magnetic forces belonging to the earth merits a 

 continuance of that close attention which it has already received from, 

 the British Association, and of labours such as General Sabine has, 

 with so much ability and effect, devoted to the elucidation of the 

 subject. I may here notice that most remarkable phenomenon which 

 was seen by independent observers at two different places, on the 1st 

 of September, 1859. A sudden outburst of light, far exceeding the 

 brightness of the sun's surface, was seen to take place, and sweep 

 like a drifting cloud over a portion of the solar face. This was 

 attended with magnetic disturbances of unusual intensity, and with 

 exhibitions of aurora of extraordinary brilliancy. The identical 

 instant at which the effusion of light was observed was recorded by 

 an abrupt and strongly marked deflection in the self -registering 

 instruments at Kew. The phenomenon as seen was probably only 

 part of what actually took place, for the magnetic storm in the 

 midst of which it occurred commenced before, and continued after, 

 the event. If conjecture be allowable in such a case, we may suppose 

 that this remarkable event had some connexion with the means by 

 which the sun's heat is renovated. It is a reasonable supposition 

 that the sun was at that time in the act of receiving a more than 

 usual accession of new energy; and the theory which assigns the 

 maintenance of its power to cosmical matter, plunging into it with 

 that prodigious velocity which gravitation would impress upon it as 

 it approached to actual contact with the solar orb, would afford an 

 explanation of this sudden exhibition of intensified light, in harmony 

 with the knowledge we have now attained, that arrested motion is 

 represented by equivalent heat." 



It has certainly been a very tempting hypothesis, that quantities of 

 meteoric matter suddenly falling into the sun is the cause, or one of 

 the causes, of those disturbances to which magnetic storms on the 

 earth are due. We may, indeed, knowing that meteorites do fall into 

 the earth, assume without doubt that much more of them fall, in 



* Communication to the Eoyal Society, March 18, 1852 (' Phil. Trans./ vol. 162, 

 p. 143). 



