396 Miscellanies. 
sion has yet been distinctly improved, for the purpose above indicated ; 
nor—however probably that circumstance may be the result of a too 
limited information on my part—have I seen reason to expect that the 
one just at hand is likely to be so improved, otherwise than incidentally 
and very imperfectly. It will be impossible for the astronomers, intent 
as they must be upon telescopic observations, to do full justice to the 
phenomenon in question, and almost equally impossible for any other 
man who shall not have anticipated in his reflections the specific aspects 
to which the attention ought to be essentially devoted. 
Before quitting this topic, may I be indulged in making an inquiry 
that naturally grows out of it? Is not the light which, in a total eclipse 
of the moon, makes her dark face visible to us, derived, in a greater 
measure, from this equatorial nebula of the sun, than from the refrac- 
tive effect of the earth’s atmosphere? If the intensity and extent 
of the zodiacal effulgence shall be detected at the occurrence of the 
coming eclipse, or by any other means, it may be possible to reply 
very. satisfactorily to this inquiry. I would not unhesitatingly assume 
that a reply substantially satisfactory might not be derived from facts 
already well known. I must own that, hitherto, I have not even under- 
taken to speculate concerning the amount of illumination, at the moon’s 
surface, due to the terrestrial atmosphere,—a question which would 
seem, at first view, to be of moderate difficulty, if only the dispersive 
and refractive powers of common air are exactly ascertained. . 
But I pass on to some suggestions respecting a phenomenon of a 
different class. ‘T'o observers just within the path of total obscuration, 
—and perhaps, very transiently, to those situated deeply within it,— 
the telescope will probably reveal a fine thread of light, edging some 
part of that dark limb of the moon which is in near proximity to the 
sun’s corresponding limb. I infer this probability from a similar as- 
pect,—which may indeed have been observed at other times, and re- 
corded, although I have no knowledge that it has been,—that was wit- 
nessed by myself, through an excellent instrument, from the station of 
New York, on the occasion of the annular eclipse of 1838,—or rather 
the | eclipse which just failed to be annular, at that station, on account, 
ly, of an irregularity in the moon’s outline. In any event, it 
must be rare that the phenomenon under consideration can be exhibited 
so strikingly as it was on the occasion alluded to, from the very cit- 
cumstance of my station being at or near the limiting boundary, upon 
the earth’s surface, of the annular aspects. On that occasion I noticed, 
several minutes before the time of nearest completion of the ring, the 
fine cusps of the sun’s unobscured crescent prolonged by a hair-breadth 
line of brightness, totally diy verse, in color and intensity, from the sun’s 
. As the cusps approached, the line or thread of light in advance 
