[ 229 1 
tlbn, or agitation of the upper edge of the Sun, as in 
Tab. X. and XL fig. i . when I called out to my good 
friend, governour Vanfittart, Who was fo kind to give 
himfelf the trouble of taking the time for me, and 
defired him to take care. I had not taken this pre- 
caution above five or fix feconds, when I plainly faw 
a black notch breaking in upon the Sun’s limb, and, 
which feemed a portion of a much lefs fphere 
than that of Venus, as in fig. 2. Infiantly I 
defired Mr. Vanfittart, by the word Now, to mark the 
time, which was 11^ 57' fidereal time, by Dr, 
Halley’s little clock, belonging to the royal obfer-. 
vatory. The lafi-mentioned time, allowing for the 
neceflary corredions, and reduced to apparent time, . 
is 7*^ 1 1' 1 
As I imagined, from the infirudions of Dr. Halley, 
that the precife and accurate time of obferving the- 
internal contad is, when the thread of light flaould. 
break in between the concave, edge of the Sun and. 
the convex edge of Venus, as in fig. 6. L waited 
till that particular period, which was when Dr. Hal- 
ley’s clock marked 12^ 15' 45^^ fidereal time, or 
7'' 29' apparent time, the difference, being; 
18^ 7^"' of apparent time. 
The fame phaenomenon of a protuberance, which I: 
obferved at Madras, in I76i,*at both internal contads, 
I obferved again at this lafi tranfit : at both times, the,- 
protuberance of the upper edge of Venus diminifiied. 
nearly to a point before the thread of light between, 
the concave edge of the Sun, and the convex edge, 
was. perfeded, "when the protuberance infiantaneoufly, 
^ Pfi.llof. Trank. Ycl. Lil, parti. 1761,. p. 396. 
