on the Planet Mars. © 239 
ft, 2d, and 3d of Oétober 1783, fhews plainly, that the 
appearance of the fouthern {pot @ was a little affected by the 
diurnal motion of the planet; and the obfervations of the 3d 
and 4th of July 1781, fhew alfo that the {pot d could not be 
exaQily at the north pole; and that, perhaps, the vifible 
branch of the latter extended pretty far towards the: equator. 
However, the fouth polar fpot of the year 1783, being very 
{mall and nearly round, afforded a good opportunity for deter- 
mining its polar diftance, by noting the different angles of 
pofition it affumed while Mars revolved on its axis; to this end 
many obfervations were taken at different hours of the fame 
night, which will be found among the meafures of the angles 
of pofition in the next divifion of my fubject. And fince the 
different degrees of brilliancy, as well as the proportional ap- 
parent magnitude of the {pot, would alfo contribute to the in- 
veftigation of this point, I continued my remarks on thofe par- 
ticulars, as follows. 
1783, O&. 2. 7h. 59’. The bright fpot near the fouth pole is 
about half vifible. 
O&. 4. 8h. 0%. The polar fpot feems to project above: 
the difk as formerly, and is very fmall.. 
~~ OG. 5. 11h. 13’.. Fhe fpot is very. fmall, and feems 
aGtually to bein the circumference. 
“11h. 30’. The fpot is fmall, and feems to be with its 
fartheft fide in the circumference of the. difk ; or it- 
may, perhaps, be partly beyond it, and therefore: 
not all in fight. 
Fea 7 Ge the {pot much clearer ati I did ‘before. 
13h. 15’. The white fpot is more in fight, and of its 
_-ufual fize, but does not. feem much to change i its po-. 
e fition 3. 
