1871-] The Fuel of the Sun. 455 



actually visible until I was rather startled at rinding the 

 corona, instead of being, as I had rather loosely supposed, 

 a mere uniform filmy halo, had been described by Mr. De la 

 Rue in his Bakerian Lecture on the Eclipse of 1860, as 

 "softening off with very irregular outline, and sending off 

 some long streams," &c. I was then living on the sides of a 

 Welsh mountain far away from public libraries, and being no 

 astronomer, my own books kept me better acquainted with 

 the current progress of experimental than with astronomical 

 science. 



Even when " The Fuel of the Sun" was published I knew 

 nothing'of the American observations of the quadrangular 

 figure of the corona, or should certainly have then quoted 

 them, nor of the fact revealed by the Eclipse of December, 

 1870, that, " wherever on the solar disc a large group of 

 prominences was seen on Mr. Seabroke's map 5 there a 

 corresponding bulging out of the corona was chronicled on 

 Professor Watson's drawing ; and at the positions where no 

 prominences presented themselves, there the bright portions 

 of the corona extended to the smallest distances from the 

 sun's limb ;" and that Mr. Brothers's photographs all show 

 the corona extending much farther towards the west than 

 towards the east, the west being "the region richest in 

 solar prominences." I am sorry that the limits of this 

 paper will not permit me to enter more fully into the 

 bearings of the recent studies of the corona and the promi- 

 nences upon my explanations of solar phenomena, especially 

 as the differences between the inner and outer corona which 

 still appears to puzzle astronomers are exactly what my 

 explanation demands. I must make this the subject of 

 a separate paper, and proceed at once to the next step of 

 the general argument. 



Assuming that such ejections of solid matter are poured 

 from the prominences, to what distances may they travel ? 

 In attempting to answer this question, I confessedly ven- 

 tured upon dangerous ground, for at the time I wrote I 

 only knew that the"" force of upheaval of the prominences 

 must be enormous, probably sufficient to eject solid matter 

 beyond the orbit of the earth and even beyond that of 

 Mars. Actual measurements of the eruptive velocity of the 

 solar prominences have since been made, and they are 

 so great as to relieve me of my quantitative difficulty, and 

 show that I was quite justified in the bold inference that 

 these eruptions may account for the zodiacal light, the 

 zones of meteors into which our earth is sometimes plunged, 

 and even the outer zone of larger bodies, the asteroids. 



