[ J 9* ] 
// 
At 8 16 
C Penumbra almoft black, and the touch 
£ a little broader. 
Slight black in the point of contact, 
81648 
8 16 49 
8 16 50 More fo. 
8 16 51 More foX 
8 16 52 More fo 
and the edges a little broader. 
True black in the point of contact, 
and the edges a little broader. 
f Here I concluded with my- 
felf, that obfervers would 
differ in their judgments 
about the moment of con- 
tad, fomefecondsoftime, 
or that fome would efti- 
mate the contad fooner 
than others. 
From thefe obfervations, I concluded, that the 
thread of light in the point of contad was fo obfcured, 
as to be undifcernible at 8 h it' 46", and that true 
black did not fucceed in the fame point, till 3" after, 
namely, 8 h 16' 49"; and from * both of thefe pro- 
perties. 
* As the fix feet Newtonian telefcope magnified four times as 
much as that of the two feet Gregorian telefcope, and the va- 
niihing of the thread of light, from its leaft degree of dufkifhnefs 
to a true black, was about 3 feconds of time by the fix feet te- 
lefcope, the time in which the thread of light was vanifhing 
from the leaf!: degree of dufkifhnefs to a true black, by a two 
feet Gregorian refledor, may be fuppofed to have been 4 times 3 
~ 12 feconds of time ; and hence an error, or rather difference, 
of pronunciation, but not of judgment, rray have arifen among 
good obfervers, if fome eftimated the contad by the invifibility 
of the thread of light, and others by an apparent blacknefs in the 
point of contad, or, which is the fame thing, the time when 
the planet had made the leaft apparent dent in the fun’s limb, 
®f 
5 
