116 
meafured by M. Cavendiih; he has feen 
Jarge balls of lead, well fufpended, ap- 
proximate from their attraétion ; and hence 
he concludes, that the attra€tion of the 
Earth, taken in totality, is fix times larger 
than that of the water. . 
The number of the comets obferved 
has been enlarged to ninety-three; and 
there were only forty-three when I began, 
at Bourg, to caft a curious and eager eye 
on that which aftonifhed the world in 
4744, and which feemed to inform me that 
I was devoted by Nature to the’contem- 
plation of the heavens. But although 
there have been fifty .difcovered, many 
more would probably have been found if 
they had been fought for more frequently : 
a remark which has induced me to found 
a prize in the Inftitute, that a gold medal 
may be decreed every year to the perfon 
who fhall have made the moft curious aftro- 
nomical obfervation. It is fo eafy to find 
comets, that Citizen Pons, Curator of the 
Oblervatory of Marfeilles, an illiterate ar- 
tift, found one laft year, as foon as he 
learned that I had depofited 600 francs 
with my notary for the perfon who fhould 
find a comet. 
But when we thought that nothing more 
remained to difcover in the heavens befide 
comets, I was equally furprifed and pleaf- 
ed to learn that one of my pupils, M. Pi- 
azzi, had difcovered a new planet, on she 
firft day of the eighteenth century, at Pa- 
Jermo, in Sicily. Itis fituated between 
Mars and Jupiter, atthe diftance of ninety- 
five millions of leagues, and performs its 
revolution in four years and feven months. 
Jt is much {maller than any of the other 
planets, and eventhan the Moon, which 
is only a fecendary planet. j 
We were employed in obferving the 
planet of Piazzi; and M. Olbers, a phy6- 
cian of Bremen, who had ebéferved it in 
the month of January, near the twentieth 
ftar of Virgo, was proceeding to revile the 
fame ftars. He remarked, on the 28th of 
March, that the twentieth, which he had 
always feen alone, was accompanied with 
a very {mall far, which he had not feen in 
his firft obfervations. He quickly derer- 
mined its pofition, and Having been em- 
ployed about it for two hours, he faw that 
it had already changed its pofition. This 
Jucky chance caufed him thus to recog- 
nize a tenth planet. It was difputed tor 
fome time whether or no it werea comet ; 
but Citizen Burckhardt, one of our mof 
fkilful afronomers, having been long in- 
veftigating it, found that it did not depart 
from the interval included between the 
Confiderations on the Progrefs of Aftronomy. 
[ Sept. I 3 
orbits of Mars and of Jupiter. But -hi- 
therto we have been accuftomed to call 
comets thofe ftars which are for a little 
fpace within the limits of our fight, and_ 
afterwards a long time invifible by their 
diftance. 
The planet of Olbers revolves about the 
Sun in four years and eight months. Jts 
mean diftance is ninety-fix millions of 
leagues ; but that which diftinguifhes it 
from all the other planets is its great ec- 
centricity and its great inclination. It 
goes a great way out of the Zodiac, in 
which all the others are included. Its in- 
clination is 35°, whilft Venus never devi- 
ates more than 8°; and the difference of 
its diftances isneara quarter, which gives 
it 28° of inequality, whilft Mercury has 
only 24°. This planet deftroys the hy- 
pothefis of -the phyficlogifts who have 
thought that all the planets of the foiar 
fyfi'em approximate to the fame plan, be- 
caufe they had all been firft impelled by a 
common caufe. This laft planet differs 
too much to be accommodable to this fyf- 
tem. rai 
The volcanoes of the Moon, the geo- 
graphical difcoveries in all parts of the - 
globe, two thouland nebulous fpots in the - 
heavens, (till remain curious refults of the 
new aftronomy. 
It is thus that fcience has made an un~ 
expected and extraordinary progrefs for 
fome years paft, and this will doubtlefs 
continue, fromthe emulative competition _ 
of {uch great geemeters and fuch fkilful 
obfervers. “The geometers are all at Pa- 
ris; but the obfervators are difleminated 
through all parts of Europe. I orghtto 
notice particularly, at Paris, Citizens Me- 
chain, Delambre, Burckhardt, and- La- 
lande, my nephew; in England, M. Her- 
{chel and M. Mafkelyne ; at Gotha, M. 
the Baron de Zach ; at Milan, Citizens 
Oriani-de Cefaris and Reggio ; at Paler- 
mo, M. Piazzi; at Marfeilles, M. Thulis, 
at Montaubon, Citizen Due la Chapelle 5 
at Berlin, M. Bode; and at Mirepoix, 
Citizen Vidal, who has alone made more 
obfervations of Mercury than all the afiro- 
nomers taken together for the latt two 
thoufand five hundred years. This afto- 
nifhing obferver is only, however, a fim- 
ple inhabitant of a city fmaller than ours, 
who is not even known at Mirepoix, but 
whole zeal appertains to the univerie and 
to pofterity. For my part, I have, in- 
deed, caufed an obfervatory to be built at 
Bourg, bui have not yet been able to col- 
lect a fingle obfervation in it. 
@ for 
