]40 THE CANADIAN NATURALIST. [Ju 



ne 



sliglitly dim, without actually reversing, the bright lines of the 

 chromosphere. But with the bright line at G7.0 divisions of my 

 Bcale the case is different. If I have rightly identified its wave- 

 length, it does reverse the solar spectrum, for the rays whose wave- 

 lengths are 530.7 and 528.8 are respectively identical with the 

 dark lines at 1487.7 and 1508.6 of Kirchoff's maps. 



What is the corona, and of what does it consist ? If Prof. 

 Youn<ji; is correct, do the three brio;ht lines which he observed, 

 belong to some unknown element — a gas lighter than hydrogen, 

 and which, like the hypothetical ether, fills space] We can 

 hardly suppose such intense action as exists on the surface of the 

 sun to be unaccompanied by electricity, which, in the auroral 

 light of our own heavens and the corona of the sun, may render 

 this hypothetical gas luminous, i^torey, years ago, discussed the 

 likelihood of such an extra-atmospheric medium. If Prof. 

 Young's observations are corroborated by those of others, there 

 may be found some probable proof for such a supposition. 



Are the corona and the zodiacal light identical ? Major, in 

 his essay, "The Dynamics of the Heavens," off'ers an explanation 

 of the zodiacal light, as follows: — 



" As cosmical masses stream from all sides in immense numbers 

 towards the sun, it follows that they must become more and more 

 crowded as they approach thereto. The conjecture at once 

 suggests itself, that the zodiacal light, the nebulous light of vast 

 dimensions which surrounds the sun, owes its origin to such 

 closely-packed asteroids. However it may be, this much is cer- 

 tain, the phenomenon is caused by matter which moves according 

 to the same laws as the planets, round the sun ; and it conse- 

 quently follows that the whole mass which originates the zodiacal 

 light is continually approaching the sun and falling into it. This 

 light does not surround the sun uniformly on all sides — that is to 

 say, it has not the form of a sphere, but that of a thin convex 

 lens, the greater diameter of which is in the plane of the solar 

 equator ; and, consequently, it has, to an observer on our globe, 

 a pyramidal form. Such lenticular distribution of the masses in 

 the universe is repeated in a remarkable manner in the distribu- 

 tion of the planets and the fixed stars." ^ May, then, the 

 zodiacal and coronal light be one and the same ? Supposing the 

 above hypothesis to be correct, would not the asteroids, falling in 



* Page 272 of Tollman's " Collection of Essays on the Correlation and 

 Conservation of Forces." 



