32 SCIENCE IN SHORT CHAPTERS. 



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. 



But how, the reader will ask, can such solids, ejected 

 from the snn, acquire orbital paths around him " We have 

 been taught that the parabola is the necessary path of such 

 ejections." Mr. Proctor has evidently reasoned in this 

 manner, for in last April number of " Fraser's Magazine" 

 he says that some of my ideas are " opposed to any known 

 laws, physical or dynamical," that " there is nothing abso- 

 lutely incredible in the conception that masses of gaseous, 

 liquid, or solid matter should be flung to a height exceeding 

 manifold that of the loftiest of the colored prominences; 

 whereas it is not only incredible, but impossible, that such 

 matter should in any case come to circle in a closed orbit 

 round the sun." 



More careful reading would have shown Mr. Proctor that 

 I have considered other conditions besides those of the text- 

 books, that the case is by no means one of simple radial 

 projection from a fixed body into free space and undis- 

 turbed return. I distinctly stated that " the recent ejections 

 may have any form of orbit within the boundaries of the 

 conic sections," from a straight line returning upon itself, 

 due to absolutely vertical projection, to a circular orbit pro- 

 duced by the tangential projection of such curving promi- 

 nences as the ram's horn, etc. The outline of the zodiacal 

 light would be formed by the termination or aphelion portion 

 of these excursions, or of such a number of them as should 

 be sufficient to produce a visible result. 



Again, speaking of the asteroids, in Chapter xiv., I 

 state that "I should have expected a still greater elonga- 

 tion and eccentricity in some of them, and such orbits may 

 have existed ; but an asteroid with an orbit of cometary 

 eccentricity that would in the course of each revolution 

 cross the paths of Mercury, Venus, the Earth, and Mars in 

 nearly the same plane, and dive through the thickly scat- 

 tered zodiacal cluster, both in going to the sun and return- 



