1798.) 
or confining himfelf to the tropic of Ca- 
pricorn, and by illuftrating the threads 
with an achromatic magnifying glafs of 
two inches aperture. 
I mention all thefe conditions becaufe 
they limit prodigioufly the number of 
{tars which we can obferve ; perhaps there 
would be 300,000 in the whole furface 
of the heavens, vifible with the fame 
glafs; and the telefcope of M. Her‘fchell, 
which has 45 times more aperture, that 
is to fay, 324 times more light, would 
fhew 90 millions ; which is doubtlefs but 
a fmall number in comparifon ot what 
exilts. 
The minifter at war, citizen SCHERER, 
has. written to the commandant of the 
Ecole militaire, that the obfervatory and 
the aftronomers be no longer oppoied or 
checked by the ignorance of the troops. 
Citizen La Puack, who had already 
made three of the fineft difcoveries which 
were wanting to improve our knowledge 
of the higher aftronomy, announced to 
me, March 2sth, that he had found a fe- 
cular equation for the apogee and for the 
nodes of the moon; the firft is 4 3 of 
p fe) 
that of the moon; the fecond is the 1 
both oppofite tothat of the moon. T hus 
anew point is gainea in the theory of 
the moon, of which he expects here- 
after to make ufe, aflifted by Citizen 
De LamBRE, who is worthy from his 
ability in aftronomical calculations to be 
an affociate in this important labour. 
We fhall then have fome years hence new 
tables of the moon, which will greatly 
furpafs thofe publifhed in England, and 
which will render new affiftance to the 
marine, for the obfervation of the longi- 
tudes. 
Citizen Bouvarp has calculated fome 
lunar obfervations of Bradley and Mafke- 
lyne between 1750 and 17953 in order to 
fix this equation of the apogee which ci- 
tizen La Piace had found by theory, 
which will diminifh the errors of the lu- 
nar tables ; we fhall caufe the lunar ta~ 
bles to be printed together with thefe cor- 
rections. 
The completion of this labour will 
take perhaps feven or eight years ; when 
accomplifhed, it will be the fineft union 
of theory with obfervations, which has 
been ever made for the progrefs of aftro- 
nomy and the fervice of navigation, 
We had defiened to employ the ob- 
fervations made in England and France 
for about a century, paft ; but we are now 
. 6 
arrived at the péint where the obferva- 
sions of pat ages are of no fervice 5 for 
Hiftory of Aftronomy for 1797. 2.65 
‘between the obfervations of Bradley made 
in 4750, or thofe of the citizens LE Mon- 
NIER, and thofe which are now making, 
we need not fear more than ten feconds ot 
error for an interval of 50 years; this 
would make 20 feconds tor a century, 
and certainly there are 30 leconds of pro- 
bable error in the beft obfervations of the 
laft age, both on account of the nature 
of the inftruments, and of the proper 
motion of the ftars which renders their 
pofition uncertain at that epoch. In the 
memoirs of 1781, wherein I compared. 
213 pofitions of Flamitead’s ftars, there 
were 41 where the difference exceeded a 
minute, and 86 where it paffed 30 fe- 
conds. This is fufhcient to fhew that 
we fhall reap fome advantage from em- 
ploying the obfervations made the laft so 
years with new inftruments ; with great 
reafon may we abandon thole of the Ba- 
bylonians made 2500 years ago; they are 
so times more diftant, but are from 60 
to 80 times lefs accurate, as I myfelf 
have remarked ; having palled much time 
in inveftigating the obfervations of Mer- 
cury, which are in Ptolemy, and from 
which I have derived very little advan- 
tage. | 
We have had this year a Comet, which, 
although fmall, was neverthelefs vifible 
to the naked eye. Citizen Bouvarp, 
who labours in the obf{ervatory with zea] 
and afliduity, and particularly applies 
hinfelf to the refearch of comets, was 
concerned to find that the one which he 
difcovered November 14th, 1795, had 
been obferved in Germany two days. be- 
fore. 
This year, after having been many 
months on the fearch; he tound one Au- 
gut 14th, at ten o’clock in the evening ; 
but when he had found it by the glafs, 
he perceived that it was diltinguifhebl: 
by the naked eye, and he therefore con- 
cluded it would be feen by other aftrone- 
mers. In this difcovery however he was 
the firft. The next day it was feen at 
Leipiig by Monfieur RupiGeR, at Pa- 
dua by M, Toatpo, at Palermo by M. 
Pyazzi1, and even at Sinope on the Black 
Sea, by Citizen RECEVEUR, who accom- 
panied Citizen BEAUCHAMP in his Ara- 
bian voyage. Onithe16th the comet had 
become larger, it was feen at Mirepoix 
by citizen VIDAL, who has fent us many 
obferyations upon it, and remarks that it 
was feen by many of the country people ; 
it was perceived in Auftria by M. Tra- 
TINICK, at Berlin by M. Bong, at Bre- 
men by M. OLBERS, at Viviers by M. 
FLAUGERGUES, at Marfeilles by M. 
BLANc: 
