[ *j« ] 
which was done at Nuremberg in Germany , by Mr. 
Wurtzelbaur , and at Tans by Monjieur CaJJini: At 
Greenwich Clouds prevented it. At Nuremberg Mr. 
Wurtzelbaur obfervcd Mercury to go off of the Disk 
ol the Sun * at s h 45 - mane about 73 \ Degrees from 
the Vertex of th£ Sun to the Right Hand 5 and Mon- 
jieur CaJJini obferved the fame accurately at 8 h 10' 
24 y/ mane > therefore from the known Difference of 
Meridians of thefe Places, the Egrefs mud have hap- 
pened at Greenwich at 8h 1 f mane. 
The Obfervation of Mr. Wurtzelbaur will greatly 
avail at coming at the Duration of the Tranfit . It is 
mentioned, that Mercury left the Limb of the Sun 
73° 30' from his Vertex to the Right. Now at that 
time at Nuremberg , the Angle of the Ecliptic with 
the Vertical palling through the Suns Centre, was 
420 3 ' 5 // ; therefore the lad Point of Contact on the 
Suns Limb was obferved 31 0 26' 55" from the 
Ecliptic to the South, and confequently his Latitude 
was 8 / 28" South at that time. 
To find the Point on the Suns Limb of the Ingrefs, 
in order to come at the Duration of the Tranjit , we 
mud be beholden to Computation, and the Theory of 
Mercury's Motion: I have therefore, from the Tables 
from which the above Times of the Tranjit of 1743 
are drawn, carefully computed his Motion along his 
Path eroding the Disk of the Sun> and find that he 
moved along it after the Rate of 5 7 si" i in an Hour, 
and the Difference of Latitude in 5 Hours 4' 2 1 ", and 
his Elongation 29' 7 " : Therefore the Angle of his 
* Vertex to the Right, it fays, a Nadir Solis ad dextras • but it 
is a manifeft Miftake, as any one upon Trial may find. 
vifiblc 
