1808.] 
associates, and calling the attention of 
chemists and naturalists vo this subject, 
that he was induced to read the memoir, 
of which M, Delambre has given the 
account. 
An eclipse of the sun is a phenomenon 
equally useful in order to verify astro- 
nomical tables, and to determine geo- 
graphical longitudes; it is one besides 
which of all others attracts most the 
attention of observers. M. Lalande, in 
conformity to a practice he had follow- 
ed, for more than fifty years, calculated 
all the observations he could collect, 
respecting that of 1806. The inter- 
vention of clouds concealed it from the 
view of the astronomers of Paris, but 
it was observed in several parts of France, 
Germany, Holland, and Italy. It was 
in America, however, where it must 
have been most interesting, since it was 
total at Boston and Albany. At Kin- 
derhook, near this last city, M. Ferrers 
observed it with very excellent instru- 
ments. According to him, the con- 
junction took place at 11h. 45’ 33”, M. 
Lalande found exactly. the same, and 
as it was known by other observations, 
that it happened at Paris; at 4h. 306”, 
the difference of longitude is therefore 
Th. 15! 97", Ge 
The same eclipse was 
at Albany, but at the instant of returning, 
light the observer happened.not to have’ 
his eye applied to the glass ; and-though 
this phenomenon appears to. be of a 
nature to be equally well -observéd- by 
the naked eyes, it yet shoul@ seem, that: 
» conclusion as the first, and the same 
feonsequence will be confirmed by all 
he had been some seconds too late. . _ 
* A curious remark of M- Fefrers ‘4s, 
that the disc. of the moon: appedred 
enlightened a few seconds before the 
end of the total eclipse, which ‘he con- 
siders as an effect of the moon’s atmo-_ 
sphere. 
The obscurity was not so great as 
might have been supposed; he saw only 
six principal stars or planets. A luminous 
ring from 45 to 50’, which surrounded 
the sun, in some degree lessened the 
darkness. 
From a comparison of this total eclipse 
with some annular eclipses formerly 
observed, M. Lalande is of opinion, 
that the irradiation of the sun is at 3” 
und that it is necessary to add 1” to the 
semi-diameter of the moon, which he 
had determined by direct observations 
made at the time of the full moon, 
Several astronomers are of opinion, 
that the sun is not immoveably fixed in 
a single pomt of space, M. Lalande, 
Proceedings of Learned Socteties 
also observéd. 
OL: 
from the common motion of rotation, 
which is generally admitted, supposed: 
that it might possess a motion of transla 
tion. This, which he threw out as a 
mere conjecture, Dr. Herschel-has un- 
dertaken to prove by observations; he 
“appears even to be confident that he 
could determine the point of the heavens, 
towards which the sun advances with 
all his planetary train. M. Prevot, a 
member of the academy of Petersburgh 
had drawn the same conclusion; but M. 
de Sejour, having treated the question 
analytrcally, was of opinion, that it cannot 
be resolved when considered in all its 
extent, which has led Dr. Herschel again 
to resume the subject in the Philosophical 
Transactions for 1805. 
If the motions that are remarked in 
several stars are only apparent, and 
produced hy the movement of the sun 
itself, which approaches some while it 
recedes from those on the opposite side 
of the heavens, all these apparent motions 
would be parallel between themselves, 
and to the motion of the sun. These 
motiong; are very slow, and so far as 
they have been-hitherto observed form 
only small arcs; but if we prolong them 
in idea, they must form large circles, 
which will intersect each other at the 
same ‘point, of the heavens, and this 
‘point must be that, towards which all 
the planetary system tends. The well 
kNOWA motions of two stars are suiticient. 
to determine this point, if the observa- 
tions be accurate, and the principles just. 
Two other stars would lead to the same 
the other stars that can be observed in 
pairs, Dr Herschel undertook to observe: 
m this way the most brilliant stars in the 
Catalogue of Maskelyne. ‘The results 
¢of these labours are not, however, suffi-. 
ciently decisive to establish the motion 
of the sun, and the immobility of the 
stars; it should rather seem, that they 
have each a distinct motion, and without 
admittingsthis sepposition, M. Sejour 
is of opinion, that the problem cannot 
be solved. Notwithstanding this deci- 
sion, M. Burckhardt has submitted it 
anew to the strictest analysis. His 
formule are more- commodious, and 
more susceptible of application than 
those of M. de Sejour, and much less 
complex than the trigonometrical cal. 
culation of Dr. Herschel. We has, with 
great propriety, rejected the distances 
of the stars which appear, and are really 
ong of the elenents of that-calculation, 
Aid 
