386 ANNUAL OF SCIENTIFIC DISCOVERY. 



the most careful of these observers had distinctly remarked that the 

 red flames disappeared on the one side, and reappeared unchanged on 

 the other side, thus confirming his (Professor Airy's) observations. 



He would now come to the eclipse of 18GO. That eclipse began 

 on the western coast of America at sunrise ; it passed through South 

 America to the south of Britain, thence to Spain, and through Alge- 

 ria to the Red sea, where it terminated at sunset. Preparations were 

 made to observe this great eclipse by different persons and bodies. 

 The British government, at his (Airy's) suggestion, granted a large 

 steamer the Himalaya for the purpose of conveying a large 

 party of English astronomers to Spain, and it was principally from 

 the observations of this party that he should make up the statement 

 he was about to lay before the Association. The astronomer royal 

 then proceeded to describe, by the aid of diagrams, the appearance 

 of the corona, with respect to which he remarked that the accounts 

 he received were a mass of discordance. He particularly alluded to 

 the appearance of the planets Venus and Jupiter, which shone out 

 near the sun as if there had been no sun in the hemisphere. Mr. 

 Plantamour, of Geneva, who went to a place on the eastern coast of 

 Spain, took three drawings at the beginning, the end, and the mid- 

 dle of totality. What he depicted seemed to show that the appear- 

 ances were produced by something like a cloud', or a cloudy atmos- 

 phere, between the earth and the moon. It could not be from any- 

 thing in our atmosphere. Was there an atmosphere extending from 

 the earth to the moon ? He (Professor Airy) declared that he knew 

 not ; but he knew nothing else that would 'account for what Mr. 

 Plantamour depicted. The whole train of observations on the corona 

 led him (Professor Airy) to believe that there was some reflecting 

 medium extending almost, if not quite, from the earth to the moon. 

 He did not know whether that was incompatible with what was 

 known of the interplanetary atmosphere ; but there was nothing else 

 that supported these appearances, and this theory did so in some 

 measure. It was also supported by the observation of polarization. 

 When light was not reflected, it was only the common vulgar light ; 

 but when reflected from the surface of a transparent medium, it re- 

 ceived the modification of polarization. So, when that modification 

 was discovered, it was inferred, with great probability, that the light 

 had been reflected. If we did that, we should be going a long way 

 towards showing that the light in this case was produced by something 

 like an atmosphere intermediate between the earth and moon. The 

 learned professor showed, by an experiment, that two images of light, 

 in the ordinary state, could be made to revolve round each other 

 without alteration in intensity ; but that, when reflected from unsil- 

 vered glass, the lights disappeared alternately while revolving ; and 

 that the same effect resulted when the rays were colored. Some of 

 ; the Himalaya party were prepared specially to observe whether the 

 light from the corona or other parts was polarized. The result was 

 this : Some of the English observers were abundantly satisfied that the 

 light of the corona was polarized ; but they could not decide whether 

 or not the polarization was of a character that implied reflection 

 in the plane passing lengthwise of the rays ; but one of the for- 

 eign observers who went to the east of Spain saw that it was so 



