HISTORY OF PHYSICAL ASTRONOMY.

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of the lunar disk from behind which the first ray of light was about toissue, a narrow streak of rose-coloured red light, which extended, perhaps,oxer an arc of 70° or 80° along the moon’s limb, and which disappearedwith the luminous ring and the rose-coloured mountains as soon as thefirst ray of the sun darted forth *.

M. Otto Struve was under the impression that, immediately before thedisappearance of the sun, he perceived a red streak of light along themoon’s limb, about 45° from the point where the total immersion tookplace f.

The radial appearance noticed during the total eclipse of 1842, imme-diately before and after the complete obscuration, is also a phenomenonwhich obviously indicates the existence of a solar atmosphere. Thus, inthe description of the eclipse ascribed to Mrs. Airy, it is affirmed, that withrespect to the place where the sun had gone in, and that where he wasabout to emerge, the light came out successively like little beams from themoon's edge\. Moreover, it is stated that the light of the ring did notpresent any remarkable change until the little flame-coloured beams shotout for a few' seconds before the reappearance. This emanation of red raysin a direction perpendicular to the moon’s limb, can only be accounted forby supposing the rays of the sun to be obstructed in their progress out-wards, by a dense atmosphere enveloping the solar surface and exercisingan influence on the primitive rays of the spectrum similar to that pro-duced by the terrestrial atmosphere.

The accounts respecting annular eclipses are not wanting in allusionsto phenomena indicative of a solar atmosphere, analogous to those whichhave been already noticed. A brief review of those which more especiallybear on the subject, cannot fail to prove interesting to the reader.

Maclaurin , in his account of the annular eclipse of 1737, states that alittle before the formation of the ring, a remarkable point or speck ofpale light appeared near the middle of the part of the moon’s limb thatwas not yet come upon the disk of the sun, and that a gleam o f light morefaint than this light seemed to be extended from it to each horn. Thisphenomenon was seen about fifteen seconds previous to the projection ofthe whole body of the moon upon the solar disk §.

Maclaurin also states that Lord Aberdour, who observed the sameeclipse, remarked that a narrow streak of a dusky red light coloured thedark edge of the moon, immediately before the ring was completed, andafter it was dissolved j|.

Van Swinden, in his account of the annular eclipse of September 7,1820, as observed by him at Amsterdam , states that just before theannulus was formed, he perceived above the yet immersed limb of thesun, a very small arch of light, which was no part of the solar disk. Healso adds that the space between it and the moon’s dark limb was notilluminated. It might have been compared, as to colour and appearance,with the end of the flame of an argand lamp projecting beyond thechimney or glass tube V.

* Annuaire, 1846, p. 437. t Ibid., p. 437.

j: Mem. Ast. Soc., vol. xv., p. 16.

§ Phil. Trans., 1737, p. 181. || Ibid., p. 182.

^ Mem. Ast. Soc. vol. i., p. 145. Van Swinden mentions, in the account of hisobservations, that during the annular eclipse of 1764, a similar arc of faint light was seenaround the moon’s limb at Toulouse , by M, Darijuier.