Chemistry Of The Sun

In conneetion with the photography of tb&solar spectrum considerable advances have been made in the recognition of the chemieal elements present in the sun. Copper, silver and vandaium have been transierred from the list of che doubtful metáis there to the certain; and very recently Rowland has found clear evidence of the presence of silicon, the apparent absence of which has been long a standing puzzle. The evidence in favor of the presence of carbon also seeins to gain strength, and the same is true in the cases of aluminum, cadmium and zinc. The fact that the lines whieh reveal the presence of silicon are almost entirely in the ultra-violet, invisible portion of the spectrum warrants the expectation that photography may soon flnd there evidence of sorae of the other still missing elements, such as boron, phosphorus and Bulphur. But no new light yet appears in reference to the mysterious absence from the sun of oxygen, nitrogen and chlorine, which play so important a part in the chemistry of the earth, except, indeed, tliat the results obtained by Janssen last summer on the summit of Mont Blanc u-e conclusive that the great "B" line of oxygon whieh is so conspicuous in the solar spectrum when the sun is near the horizon is entirely of earthly origin, and not in the least solar, writos l'rof. Young, of Princeton, to the Youth's Companion. The veteran astronomer, still enthusiastie and full of pluck, though unable to ondure any severe physical exertion, had himscli carried by a small rmy of gnides and porters to the very summit of the mountain, and there obtained decisivo observations. As regards the "photosphcre"' - the luminous surface of the sun - and sun spots, there is little neus to note. Janssen at Meudon has made real improvcment in the processes of photogTaphing the spots and the details of the solar surfaee, and recent observations of the displacement of the lines f the spectrum at the eastern and ■western edg-es of the sun made by Duner, of Upsala, have confirmed the laws of the sun's swifter rotation at the equator - a law which, though first discovered more than thirty years ago, has recently been called in question. It still remains as much a mystery as ever how the great cavities which we see as spots come to be formed in the sun's surface, why they are so limited to the two zones on each side of the sun's equator, and why they show such a regular increase ahd decrease in r.um'"e'-s every eleven years.