XXX INTRODUCTION. 



the general mass of data namely, that as the spectator's place is changed relatively to different 

 portions of the nebulous ring, such portions change, for him, their reflected light ; just as is done 

 every day, to our eye, by clouds or other terrestrial objects. Remembering this, he will, I 

 think, fully understand why, when I was on the northern .side of the ecliptic i. e. towards the 

 northern edge of the ring its reflection was chiefly on that side ; why its southern portions gave 

 me the chief reflection when I was towards its southern side ; and so, why all the various aspects 

 detailed in Nos. 1, 2, 3, 4, and 5, of I, were, at different hours or seasons, presented to my 

 eye. 



If it should be objected to my deductions from Bouguer's law of reflection, that the intensity 

 of light, which his results would give this ring when brought between our eye and the sun, 

 ought to make the ring a very striking object to us during a total eclipse of the sun; I reply, 

 that the increased intensity of the Zodiacal Light, from the apex to base, is a fact independent 

 of any theories; that, on any supposition of causes, it can scarcely be doubted that this reflec- 

 tion, so increasing from apex to base at the horizon, goes on still increasing in force below the 

 horizon, towards the direct line between our eye and the sun; and that, consequently, if the 

 Zodiacal Light is not a striking object in a total eclipse, stretching off from each side of the sun, 

 this fact is not more against the hypothesis of a ring around our earth, than against a ring 

 around the sun or in any other place. As respects such eclipses, however, if the observer of 

 them is in a high latitude, north or south, he will, except at only one portion of the year, have 

 the ecliptic at a very low angle with his horizon (even, under the best circumstances, not at a 

 high angle), and therefore cannot expect to have a good exhibition of the Zodiacal Light at 

 the time of eclipse. There was, however, an observation made in Peru, during a total eclipse, 

 on the 30th of November, 1853, from which we might expect something of a more decisive 

 character. The observer was Professor Carlos Moesta, of the Observatory of Santiago, who, at 

 the suggestion of Lieutenant Gillis, U. S. N., was sent to Peru, by the government of Chili, 

 for that purpose, and who afterwards made a highly interesting and valuable report to the 

 Minister of Public Instruction, with a sketch of the heavens as they appeared at the time of 

 the total obscuration of the sun. His place of observation was in lat. 14 21' 21" S., and con- 

 sequently he had the ecliptic at a high angle with his horizon: the sun at that time having a 

 declination of 24 42' S. i. e. 7 21' south of the observer. Every thing was favorable, as re- 

 gards an observation for the Zodiacal Light, on that occasion ; and we have, in his engraved 

 plate, in addition to the corona usual in total eclipses, a long ray projecting from the sun S. 

 70 E., and another, also a prominent and striking object, but not quite so long, stretching 

 off N. 80 W. He says : "Nearly all the northern part of the ring [corona] was uniform ; the 

 opposite side was evidently composed of numerous rays, which appeared to come from the ring, 

 and all which had the same length, with the. exception of two very large ones. Of these last, 

 one was in an upward direction, and inclined about 20 S. of E., and according to estimation, 

 its upward extent is as large as a diameter of the moon ; the other extended from the ring 

 downward, not diametrically opposite to the former, but inclined about 10 N. of W., and was 

 a little shorter than the other. The appearance of these two rays was much like that of a 

 cornet, narrower at the end than near the nucleus, and clearly radiating in its structure; since 

 it could be seen, perfectly well, that these rays were not of a homogeneous light, but composed 

 of a vast number of very small rays. Soon after the eclipse I made the annexed sketch, in 

 which I have endeavored to represent this ring [corona] as nearly like the original as possible." 



It should be added to this, that Mr. Moesta's drawing was from a view through the telescope; 



