180 



THE SOLAH ECLIPSE OF 1854. 



[1855. 



lowest tempcriiture oocuiTed not at the period of greatest ob- 

 scuration, but, as might have been anticipated, somewhat later 

 — at Prescott, 16 minutes after the middle of annularity ; at 

 Kingston, about 12 minutes ; and at Toronto, 20 minutes after 

 the greatest obscuration. 



The normal fall of the temperature at Toronto on that day 

 from the beginning of the eclipse to the greatest obscuration is 

 l°-0, and that from the greatest obscuration to the end is 2°-2 ; 

 so that the diminution and increase of temperature due to the 

 obscuration and re-appearance of eleven digits of the sun's disc 

 would be respectively 3°-6 and 5°-2, the mean of which is 

 4°-4 — a result which is approximative only in so far as the 

 actual march of the temperature of that day may have coincided 

 with the normal : and the elimination of this possible discre- 

 pancy is precisely one of those points which can only be effected 

 by comparison of similar results at many stations. 



The eifect on a thermometer with blackened bulb freely 

 exposed to the sun's rays is of course much greater. At To- 

 ronto the fall was 23°-0, at Prescott 13°-0, at Kingston 16°— 

 the minimum occurring in all at the greatest obscuration ; the 

 subsequent rise to the end of the eclipse was at these stations 

 12°-2, 7°'8, and 9°, the excess of the fall above the rise being 

 due to the sun's descent in the heavens. 



It may be mentioned that at the Observatory, Toronto, in 

 addition to the usual photographic traces of the self-recording 

 magnetic instruments, eye-observations of all the instruments 

 were made consecutively during the eclipse, but no unusual 

 disturbance of any of the magnetic elements occurred. 



Among the most striking natural phenomena attending a 

 solar eclipse are the changes in the colour of the sky and the 

 aspect of terrestrial objects. Such changes are attested by ob- 

 servers on all occasions, but the precise nature of them varies 

 considerably with the particular circumstances of the locality, 

 the nature of the day, and, in no slight degree, depends also 

 on the idiosyncrasy of the observer himself. Thus we find, in 

 the historical records of different eclipses, from the year 840 

 A.D. downwards, that " the blue tint of the sky became a livid 

 colour,mixedwithashadeofpurple;"i that "the solar light passed 

 during the progress of a solar eclipse, from its ordinary white 

 to yellow, then to orange, and finally, before complete immer- 

 sion, the last rays were reddish ;"^ that the character of the 

 complete obscurity was a " tint wan and livid, a shading of 

 olive-grey, which threw over nature, as it were, a veil of 

 woe;"3 that " on the horizon over the sea line was a large band 

 of red orange ;"^ and again, " on the horizon opposite the sun 

 rose a belt of from 15 to 20 degrees in altitude, whose colour 

 resembled that of red copper, while higher up, the sky was of 

 a sombre violet-tinted azure. "^ In another account, we read 

 that as the obscurity increased, the remaining daylight had a 

 yellowish tinge, and the azure blue of the sky deepened to a 

 purplish violet hue, and during the complete immersion, the 

 heavens, in the neighborhood of the sun, were of a uniform purple 

 grey colour, in the zenith of a purplish ^ violet, and oppo- 

 site the sun, broad bands of yellowish-crimson, intensely 

 bright, pervaded large portions of the sky, while the sea turned 

 lurid red.** Other observers note the increasing darkness to 

 be accompanied by a peculiar greenish hue f in the zenith the 

 clear blue turning purple black f and oppcsite the sun, up- 

 wards from the horizon, the sky being largely and brilliantly 

 illuminated with rosy red f or as others describe it, " with 

 magnificent yellow-orange or amber colour, contrasting strongly 



with the dark purplish-grey of the sky overhead, while in the 

 neighbourhood of the sun a sombre leaden hue prevailed."!" 



Equally striking are the various notices of the changes in 

 the aspect of terrestrial objects. So far back as 1706, it was 

 observed by Plantade and Clapies, that " when eight digits 

 were eclipsed, objects appeared of an orange-yellow, and at 

 eleven and a half they assumed a red tinge." The attention 

 of observers having been especially directed to this point by 

 Arago, the eclipse of 1842 furnished numerous data from dif- 

 ferent quarters extremely curious and interesting. All agree 

 that a little before the commencement of the total obscuration 

 the colour of surrounding objects became livid, and, in parti- 

 cular, the faces of persons assumed a wan and cadaverous ap- 

 pearance, the precise tint, however, being variously represented ; 

 thus, in some we read that objects appeared slightly yellowish 

 or reddish ; in others, that the paleness partook of an olive or 

 olive-green hue : again, that from a greenish tint they passed 

 gradually to saffron according to some obsen'ers; to violet, ac- 

 cording to others ; described by another, as if they had been 

 seen by a Bengal light. So the landscape of an extended plain 

 had a greenish cast, and the waters of lake and river assumed 

 a frightful leaden appearance, while the sea is described other- 

 where as glowing with lurid red. 



Before entering on the various explanations that may be 

 offered for these phenomena, we may examine what was re- 

 marked in the present eclipse, bearing in mind that we can only 

 expect in a partial eclipse indications, probably faint, of those 

 great changes attendant on a total one. 



From Kingston, we learn that " at the period of greatest 

 obscuration, the appearance of the landscape under the sun was 

 lurid, and seemed as if viewed through glasses of a neutral 

 tint. The obscuration was very palpable, aud quite different 

 from the ordinary shades of evening. Nothing remarkable 

 was observed in the portion of the heavens opposite the sun in 

 the eastern horizon." 



At St. Martin, " at 47i. 50m., till some time after the 

 greatest obscuration, the heavens appeared of a pale yellow 

 hue. . . A large mass of clouds (cum. strat.) lay on the 

 eastern horizon, which increased in blackness as the light of 

 the sun decreased." 



At Toronto, "at the greatest obscuration (57*. 04to.) a dull 

 red or brown tinge round the horizon, to E. and S.E., reflected 

 so strongly as to alfect the appearance of terrestrial objects, of 

 individuals, and their dress." 



At Prescott, a curious instance occurred of the variations 

 that may happen in the description of the same phenomena of 

 shade and colour by different individuals. 



Some time before the annularity commenced, one of the ob- 

 servei-s detected a red tinge in the increasing darkness on the 

 horizon towards the S.E., and called the attention of the rest 

 to it, but all of them denied any perception of it. Thinking it 

 might be an optical illusion arising from the continued use of 

 a coloured glass, this person rested his eye for some time, 

 and on again looking in that direction, was convinced of the 

 existence of the tint still more strongly. It was again denied 

 by the rest, who could see only a gray like that of early dawn. 

 The observation was of course set down as doubtful, but is de- 



1. Halley,1715. 



3. Pinaud and Boigiraud, 18J;2. 



5. Piola, 1842. 



7. Robertson, ]S51. 



9. Airy, 1851. 



2. Brau,1842. 

 4. DePassn. 1842. 

 6. Hind, 1851. 

 8. Airy, 1851. 

 10. Swan. 1851. 



