( 2\1 ) 
Difference of Longitude 15' 50", by how much he, at 
that Time, follow’d the Sun 9 s Center. 
If therefore, to the Arch of 1 5° 4', we add the Dou- 
ble of 8° 19', or of the Angle which the vifible Way 
made with the Ecliptick, we (hall have 29° 42' for the 
Point on the Sun 9 s weftern Limb, at which the Planet 
made his Exit, likewiie to the North of the Ecliptick. 
Hence the Chord, defcrib’d in the whole Tranfit, was 
of 137 0 14', and the Chord itfelf 3 o' 16" 5 and the 
neareft Diftance to the Sun 1 s Center 5' *6". Now the 
Horary Motion in this Chord, being 5' 5 6 // , the whole 
Duration of this Mercurial Eclipfe becomes 5 h 6'' 
' i n r efped of the Center of the Planet \ and therefore 
the neareft Approach of their Centers was at 5 11 14' 3 o ff 
at Greenwich , and the Exit at 7 h 47'i both vifible 
in our American Plantations , had there been any 
curious Perfon there cjualified to obfer\ethem. 
It follows likewife, by the obferv’d Diameter of 
Mercury , 10^ 45"' r ^ at ^ ie was vei T ^ t ^ ian 
two Minutes of Time in palling the Limb ; and, by 
the given neareft Diftance to the Sun s Center, it is con- 
cluded that he was in Conjun&ion, in Point of Longitude, 
at x g/ 15" having then precifely 6' oo ,J North La- 
titude. Nor can it be doubted, but that all this would 
have "been found exceeding near to Truth, had not^ 
the too early Letting of the Sun deprived all Europe of 
the delirable Sight. , 
There being a very remarkable Period of the Mo- 
tion of Mercury in 46 Years, in which Time, he makes 
191 Revolutions about the Sun } this Tranfit of ours 
is found to have been preceded by two others at that 
Interval : The firft, in the Year 1631, when Gajfendus 
at Paris , on the 28th Day of October, Jlyl- vet. was 
the firft that ever obferv’d this Appearance of Metcury 
within the Sun 1 s Disk, and found him to pafs off 
at 
