250 
Mr. Herscusy’s Objfervations 
1783, O&. 10. ah. 50’. Pofition of the polar fpot 7°: Rang 
with 460, very accurate. Itried a few parts lefs of 
the micrometer, but found the meafure too little. I 
fee pretty diftinétly, but the air is tremulous. 
gh. 55’. Pofition 42° 42’ ;. very difting. 
izh. 11’. Pofition 46° 30’ 5. I fee not quite fo well now 
as I could with. 
14h. 1’. Pofition 44° 12’; but hable to great uncer- 
tainty, on account of tremulous air; it becomes. 
more difficult to diftinguifh the center when the pla- 
net is not perfectly defined. ; 
O&. 16. 7h. 7’. Pofition 63° gf. By way of trial I fet 
59° 36’, which was too. {mall; alfo 60° 24’ was too- 
{mall; again, 61° 24’ wasnot largeenough. Then, 
taking a frefh meafure, I found it 62° AB which E 
thought right. 
gh. 55’. I took apes meafures, and shou the third,. 
which was 65° 0’, the beft of all, forI faw the planet 
and the {pot remarkably well. 
O&. 27. 8h. 45’. Pofition of the polar fpot 59° 3Q’.. 
I took three other meafures, of which 60? 39’ ap- 
peared. to me the beft; it was taken with long atten- 
dance and many changes and trials of the wires in. 
different pofitions; but the gibbofity of Marsis fuch, 
that meafures of the fituation of the fpot,are now no. 
longer to be depended on. 
Thefe pofitions, I believe, will be fufficient for the purpofe 
of fettling the latitude of the polar fpots, and thereby obtain- 
mg a correct meafure of the fituation of the real pole. Ihave 
referred thofe of the fouth polar {pot of the year 1783 tothe 
fame. circle which contains. the obfervations that were made-on. 
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