the expected Return of a Comet • 429 
If It fhould come to its perihelium on the ift of January 
1789, it might probably be vifible, with a good achromatic 
telefcope, in its defcent to the fun, the middle of September 
1788, and fooner or later, according as its perihelium fhould 
be fooner or later. It will approach us from the fouthern parts 
of its orbit, and therefore will firft appear with confiderable 
fouth latitude and fouth declination ; fo that perfons refiding 
nearer the equator than we do, or in fouth latitude, will have 
an opportunity of difcovering it before us. It is to be wifhed 
that it may be firft feen by fome aftronomer in fuch a fituation, 
and furnifhed with proper inftruments for fettling its place in the 
heavens, the earlieft good obfervations being moft valuable for 
determining its elliptic orbit, and proving its identity with the 
comets of 1532 and 1661. The Cape of Good Hope would 
be an excellent fituation for this purpofe. 
In order to affift aftronomers in looking out for this comet, 
I have here given its heliocentric and geocentric longitudes and 
latitudes and correfpondent diftances from the fun and earth, 
on fuppofition that it (hall come to its perihelium on January f, 
1789. But if that fhould happen fooner or later, the he- 
liocentric longitudes and latitudes and diftances from the fun 
will ftand good if applied to days as much earlier or later, as 
the time of the perihelium may happen fooner or later ; and 
the geocentric longitudes and latitudes and diftances from the 
earth mu ft be re-computed accordingly. The calculations are 
made for a parabolic orbit from the elements determined by 
Dr. Halley from Hevelius’s obfervations in 1661, only 
allowing for the preceffion of the equinoxes. The elements 
made ufe of were as follows : 
Time of perihelium January 1, 1789, at noon. 
Perihelium diftance 0,44851. 
Kkk2 
Place 
