[Sidenote: Gave a height from 33 to 281 miles, and a mean of 130 miles.] This method with 28 Auroræ gave a height from 33 to 281 miles and a mean of 130 miles. Galle has suggested (Pogg. Ann. cxlvi. p. 133) that the height of Auroræ might be calculated from the amount of divergence between the apparent altitude of the auroral corona and that indicated by the dipping-needle, a principle which has been adopted in Prof. Heis’s apparatus before described. The results do not differ materially from Professor Newton’s. The conclusions to be arrived at from the foregoing instances and opinions are certainly very puzzling. The terrestrial character of some Auroræ seems well established. The height to which these phenomena _may_ ascend is left almost a matter of conjecture, and further observations are very desirable. _Phosphorescence._ [Sidenote: Phosphorescence. Phosphorescent bands. Storm-clouds which threw out cirri. Shone with a sort of phosphorescence. Storm-cloud surrounded by glories of a phosphorescent whiteness.] In the voyage of the ‘Hansa’ (‘Recent Polar Voyages,’ p. 420), on the 9th September, 1869, at 10 P.M., Aurora gleams appeared in the west, shooting towards the south. “Radiant sheaves and phosphorescent bands mounted towards the zenith,” but the phantasmagoria quickly vanished. M. Silbermann (‘Comptes Rendus,’ lxviii. p. 1120) mentions storm-clouds which threw out tufts of cirri from their tops, which extended over the sky, and resolved into, first, fine, and afterwards more abundant rain. (I saw a fine day example of this on the Lago di Guarda, ending in a copious discharge of rain attended with loud thunder and vivid lightning.) Usually the fibres were sinuous; but in much rarer cases they became perfectly rectilinear and surrounded the cloud like a glory, and occasionally shone _with a sort of phosphorescence_. On the night of 6th September, 1865, at 11 P.M., a stormy cloud was observed in the N.N.W., and lightning was seen in the dark cumulous mass. Around this mass extended _glories of a phosphorescent whiteness_, which melted away into the darkness of the starry sky. Round the cloud was a corona, and outside this two fainter coronæ. After the cloud had sunk below the horizon the glories were still visible. [Sidenote: Sabine’s luminous cloud at Loch Scavaig, Skye. Other observations of luminous clouds.] Sabine mentions a cloud frequently enveloping Loch Scavaig, in Skye, as being at night perfectly self-luminous, and that he saw rays, similar to those of the Aurora, but produced in the cloud itself. Sabine also refers to luminous clouds mentioned in Gilbert’s Annals, and to observations by Beccaria, Deluc, the Abbé Rozier, Nicholson, and Colla; and to luminous mists as observed by Dr. Verdeil at Lausanne in 1753, and by Dr. Robinson in Ireland. [Sidenote: Aurora at Melville Island.]