si 6 Dr. Herschel’s Observations of the Transit of Mercury 
defined ; but here the sun appeared ruddy, and no very minute 
objects could be perceived. 
l i h 28'. The planet having advanced towards the preceding 
limb of the sun, it was now time to attend to the appearances 
of the interior and exterior contacts. 
1 i h 32'. 10-feet reflector. The whole disk of Mercury is as 
sharply defined as possible ; there is not the least appearance of 
any atmospheric ring, or different tinge of light, visible about 
the planet. 
1 i h 37'. Appearances remain exactly as before. 
1 i h 42'. The sharp termination of the whole mercurial disk, 
appears to be even more striking than before. This may be 
owing to its contrast with the bright limb .of the sun, which, 
having many luminous ridges in the northern zone, is remark- 
ably brilliant about the place of the planet. 
n h 44/. I was a few moments longer writing down the above 
than I should have been, to see the interior contact so com- 
pletely as I could have wished ; however, the thread of light on 
the sun’s limb was but just breaking, or broken ; but no kind 
of distortion, either of the limb or of the disk of Mercury, took 
place. 
The appearance of the planet, during the whole time of its 
emerging from the sun, remained well defined, to the very last. 
The following limb of Mercury remained sharp, till it reached 
the very edge of the sun’s disk; and vanished without occa- 
sioning the smallest distortion of the sun’s limb, in going off, 
or suffering the least alteration in its own figure. 
As soon as the planet had quitted the sun, the usual appear- 
ance of its limb was so instantly and perfectly restored, that not 
the least trace remained whereby the place of its disappearance 
