( *34 )) 
even beyond wy Hopes, making the Time of the mid, 
die, or neareft Approach of the Centers of the Sun and 
Mercury, Anno \jx\, 0 ciob. ^ U )'T. app. which 
we found by Obferyation at 5 t> i 4 '*, only 4” Minutes 
fooner ■, and, in Latitude, Mercury was but fix Seconds 
more foutherly than I then had computed it ; the Er. 
roi, in Longitude, being little more than two Diarne* 
tors of this exceeding fmail Planet ; and, in Latitude, 
but a Angle Semidituneter thereof. So, that for the Fu- 
ture, Aflronorners may trqfl: my Table ofthefe Tran- 
fits, tn Tran/a A. N° 193, to a few Minutes of Time, 
and not watt with the Uncertainty of Hours, nay 
Days, as has lately been done. 
But, in order to obtain a yet further Degree ofExad:- 
nefs by Help of this Obfervation, it may be molt ex- 
pedient to compare with it the Ingrefs I ob ferv\i at 
St. Helena ^ becaufe, in that, as well as in this, the 
Latitudes of the Planet being very fma- 11 , a little Error 
in them will not fo much affect the Longitudes. Sup- 
pofing therefore, that Anno 1677, Ottob. 27° 2i h 2$' 
15" at Sr .Helena, or 2ih y q 1 j^" 't,app. at Green- 
wich, the Center of Mercury entered on the Sun, and 
that, at that 7 ime, he was 8~ Degrees on the Sim’s 
Limb, to the. North of the Ecliptick (according to 
what is above concluded) it follows, that he had 
then 2' 2.0" North Latitude, and 16' 5" greater Longu 
tude than the Suns Center j as in this prefent Tranfit, 
Qttob. 29° a h 41' 30" T. app. at Greenwich, he had 3' 
40" North Latitude, and 15' yo" more Longitude. 
Now the apparent Geocentrick Differences of Longi- 
tude, are to the real Heliocentrick Differences, as the 
Planet’s trueDiflance from theSttn, to his Dif lance from 
the Earth j that is, in both Cafes, as 313 to 6 y 6 • 
wherefore, in 1677, Mercury wanted 34' of the 
Conjunction with the Shh^ and, in 172.3, but 34" 13', 
at 
