[ I 9 0 ] 
became darker, and threatened to obfcure the point of 
contact at the inftant it would happen ; the circum- 
ftances of which, for each of the moments of time, 
are imperfectly delineated, on account of the nearnefs 
of the lines, but more truly defcribed as follows ; (a 
right line reprefenting that part of the fun’s limb near 
where the contaCt happened, and an arch the ap- 
proaching limb of Venus, for each three feconds of 
time, from the lofs of the thread of light.) 
A diagram, reprefenting the approach of Venus to 
the fun’s limb, for each three feconds of time. [Vide 
Tab. VII.] 
In this diagram, the black fegments reprefent 
Venus, and the right lines drawn nearly at contaCl to 
them, reprefent a fmall part of the fun’s limb, as feen 
through a dark glafs ; the intermediate fpaces white, 
reprefent the Iky. In words, (for each fecond of time 
by the clock) thus : 
At 8 
8 
8 
8 
8 
8 
16 
16 
16 
1 6 
16 
16 
No diminution of light between the 
limb of Venus and that of the fun. 
Slight penumbra, or diminution of 
light, near where the contaCl was 
to be. 
Penumbra of a grey colour, near the 
fame place. 
Penumbra almoft brown, and the 
thread of light very narrow, and 
almoft loft. 
Penumbra brown, and the thread of 
light in the contact point indiftinCt, 
or loft. 
Penumbra more brown, and the touch 
the fmalleft poflible. 
At 
