For this reason he did not abandon the hypothesis, which appeared to have other elements of probability, in the general appearance of the corona, the necessity of immense electrical disturbances in the solar atmosphere as the result of the powerful vertical currents known to exist there, as well as the curious responsiveness of our terrestrial magnets to solar storms; yet he did not feel in a position to urge it strongly, but rather awaited developments. Father Secchi was disposed to think the line hydrogen, while Mr. Lockyer still believed it to be iron. [Sidenote: Dr. Schellen reviews the subject in eclipse of 1869.] Dr. Schellen, in his ‘Spectrum Analysis,’ treats the matter more in detail. Referring to the eclipse of 1869 as confirming the previous observations that the coronal spectrum was free from dark lines, he points out that Pickering, Harkness, Young, and others were agreed that with the extinction of the last rays of the sun all the Fraunhofer lines disappeared at once from the spectrum. He further says:— [Sidenote: Young observed three bright lines in the spectrum of the corona. Coincidence of these lines with three bright lines observed by Winlock in the Aurora. Corona self-luminous, and probably of a gaseous nature. Corona supposed to be a permanent polar light existing in the sun. Polar light in the sun attributed to electricity. Dr. Schellen thinks nature of the corona still a problem.] “The small instruments employed by Pickering and Harkness, with a large field of view, exhibited a spectrum obtained at once from the corona, the prominences, and the sky in the neighbourhood of the sun. These instruments showed during totality a faint continuous spectrum free from dark lines, but crossed by two or three bright lines. Young, with a spectroscope of five prisms, observed the three bright lines in the spectrum of the corona, and deduced the following positions according to Kirchhoff’s scale:—1250 ± 20, 1350 ± 20, and 1474. It had been already explained why the last and brightest of these lines was thought to belong to the corona and not to that of the prominences, and it seemed probable that the other two lines belonged also to the light of the corona, from the fact that they were both wanting in the spectrum of the prominences when observed without an eclipse. But what invested these three lines with a peculiar interest was the circumstance that they appeared to coincide exactly with the first three of the five bright lines observed by Professor Winlock in the spectrum of the Aurora Borealis. These lines of the Aurora were determined by Winlock according to Huggins’s scale; and if these be reduced to Kirchhoff’s scale, the positions of the lines would be 1247, 1351, and 1473, while the lines observed by Young were 1250, 1350, and 1474.” Dr. Schellen then points out that if it be borne in mind that Young found the positions of the two fainter lines more by