SiS POPULAR LECTURES AND ADDRESSES. 



tering 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 reason- 

 able 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 sud- 

 den 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 



