$i. si Mr. HeRsenEr’s Objervations 
taking ee By =1s.'1° 29’, which ‘is'the.complement to yw B_ 
(ors A, ecyaiig thewn to be'1s. 28° 31’) there will remain 
eM= 70s. 204, the place. of Mars in its own orbit®; that is, 
on the time abovementioned, the fun’s‘longitude on Nee il 
be 6s. 21° 4’, andthe obliquity of the martial ecliptic 28°. 42! 
being alfo given, we tht by the ufual method, ne fun's 
declination 9° 56’ fouth.” i 
The analogy between Mars and'the Bird arial by fut 
the greateft in the whole‘ folar fyftem. « Their diurnal motion is 
nearly the fame; the obliquity of their re{pective’ecliptics, on 
which the feafons depend, not very different; of all the :fupe- 
rior planets the diftance of Mars from the fun is by far the 
neareft alike to that of the earth: nor will the length of the 
martial year appear very different from that which we enjoy, 
when compared to the furprifing duration of the years of Jus 
piter, Saturn, and the Georgium Sidus. If, then; we find 
that the globe we inhabit has its polar regions frozen and co- 
vered with mountains of ice and fnow, that only partly melt 
when alternately expofed to the fur, I may well be permitted: 
to furmife that the fame caufes may probably have the fame 
effect on the globe of Mars; that the bright polar {pots are 
owing to the vivid réfle@tion of: light from frozen regions) 
and that the reduction of thefe {pots is: to be afcribed to:their 
being expofed’td the fun. In the year 1781, the fouth‘polar 
{pot was extremely large, which we ‘might well expect, fince: 
that ‘pole had ‘but: lately been involved in a whole twelve-: 
month’s darknefs and abfence of the fun; but in 1783 I found! 
it confi bape {maller than before, and it decreafed coneaaella : 
r 
* If no MELE great yee Bae gat we may add 3s, 10° 34’ to any giver i 
place of our ecliptic, which will at once reduée it to what it fhould be called on , 
the orbit pF ‘Mars, and will always be true to within a minute. 
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