S18 
| g,04096 years——-Diurnal heliocentric mo- 
tion, rz! °43,87— Annual motion, 
71° 24! 57,'6-—With thefe elements it 
would have been difficult to caloulate be-_ 
fore-hand the courle of the planet, fo as to 
be able to find it again on its re-appearing 
in the morning in Augult, if it be not at 
frit fight diftinguifhable from a ftar ef the 
Sth magnitude; ‘‘for, probably, (Clays 
Dr. Olbers) it has a confiderable eccentris 
city. In oppofition it may, perhaps, in- 
creafe. in ‘luminoulnefs, fo as to equala 
flar of the 6th magnitude. [ have little 
doubt that it will be found in La Lande’s 
Catalogue.” 
On the 16th of May Profeffor Bode 
writes to M. von Zach, ‘That it gave 
him great pleafure to find, that. M. von 
Zach agreed with him in opinion refpect- 
ing the Piazzian comet, and that Oriani 
and Piazzi himfelf incline towards the 
fame opinion.—-How often (continues he) 
have I wifhcd that I might live to witnels 
this difcovery—-I have been feveral times 
Jaughed at by others about my ideas of 
the harmonic progreflion in the diftances 
of . the... planets *****#4** | Adopting 
2,75 tor the diftance, I find? the helio- 
centric difference of longitude, betwixt the, 
aft and 23d of Jan.very well correfponding 
wituthe obfervations; the planet goes to 
‘ts node, which I placed in 24: its inclina- 
tion mufi exceed. 6° 3 andthis [ think was 
one of the caufes why it was not fooner 
difcovered.”’ 
Till towards the end of May M:, von 
Zach received no farther accounts relative 
to this tar. He had communicated to his 
friends the Parifian aftronomers the ob- 
fervations and elements calculated: and, 
not doubting that La Lande, to whom 
Piazzi had fent the fir account of the dif- 
. covery of the comet, had likewife been 
made acquainted with the fubfequent ob- 
fervations and corijeciures, herequefted him 
to fend to,bim an account of allthe particu- 
Jars that had come to his Knowledge rela- 
tive fo the new planet.: 
But to his no fmall furprife he received, 
- ia the beginning of june, feveral letters 
from Paris; one from the Senator La 
Place, dated the 29th of May ; from La 
Lande and Burckhard, of the 26th of May; 
from De Lambre, of the 24th of May; 
from Méchain, of the 26th of May; from 
Henry, of the 28th of May ; in which rone 
of thefe fx afironomers, who had commu- 
nicated feveral important ob/ervations and 
new difcoveries, writes even a fingle fyllable 
about the new planet! Méchain only makes 
mention of Piazzi’s comet ;—from which 
it appears, that fo late as the end of May 
they knew nothing of the conjecture of its 
Particulars relative to the New Planet. 
[ Noy. x, 
being a planet ; although the aftronomers — 
in Germany had been made acquainted 
therewith by Profeffor Bode already in the 
month of March.—-Méchain in his letter - 
to M. von Zach, of the 26th of May,. 
-merely fays, ‘¢Have you feen the comet, 
which the journals announce to have been 
difcovered at Palermo lait January? No 
one here has yet found it. Our aftrono- 
mers have not difcovered any fince that of © 
the month of December, 1799. I fome- 
times look out for them ; but without fuc~ 
cefs.2” : 
On the soth of June, M. von Zach 
received another letter from Profeffor 
Bode, in which he fays, ‘ Piazzi’s firft 
letter I received on the 20th of March, 
and on the next poft-day, the 23d, I an- 
fwered it. But he did not wait for my re- 
ply; and—conceive my joy and at the fame 
time my vexation!—I received a fecond 
letter from Piazzi, in which I found only 
the following few words relative to the 
newly-difcovered planet: ‘I wrote to you 
in January,- informing you that I had dif- 
covered a comet in Taurus, which comet 
I continued to obferve till the ath of 
February, when I was’ attacked by a dan- 
gerous difeafe, from which I have not en- 
tirely recovered. As foon as the ftate of 
my health will permit, I fhall calculate 
elements for it, and fend them to you, 
‘In the mean time I. have communicated 
my obfervations toM. La Lande .”—It is 
remarkable thathe ftill calls the fiar @ comet, 
as in his firf? letter.’” ! 
On the 18th of June,M.von Zachreceived - 
aletterfrom Dr. Burckhardt, in‘Paris, from 
which we learn the following particulars s 
La Lande had received Piazzi’s obferva- 
tion on the 31ft of May, when Dr. Burck- / | 
hardt immediately began to calculate its 
orbit. Two days later they received 
Von Zach’s and Oriani’s inveftigations, 
which gave them caufe to hope that the 
fuppofed comet would prove to bea pianet. — 
Dr. Burckhardt had already ‘found that 
the are defcribed by it was not confider- 
able. The fmall geocentric and heliocen- - 
tric motion of the cometfigave him a great 
deal of troublein calculating its orbit. He 
had firft chofen for this purpofe the obfers+ — 
vations of the 14th, 21ft, and 28th of Ja- 
nuary: but from this circumftance found — 
bimfelf under the neceffity of felecting the 
obfervations moft diftant in time from one- 
another, viz. thofe of the 1f and arf of 
January, and of the r1thof February. Dur- 
ing thefe 42 days the geocentric longi- 
tude of the comet varied only 3%, and the, ,. 
heliccentric/longitude only ro£°. On at- 
tempting to correét, by La Place’s me- 
theds, the parabola found by his ens y 
ie, . € 
; 
