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fo fmall a proportion, that I remained doubtFul for 
leveral feconds, whether it was any thing elfe ; thus 
it continued, making a deeper impreffion, with that 
tremulous motion, for about ten feconds, when the 
tremor where Venus was in contact ceafed, and the 
indenture was truly circular, with an even termi- 
nation* 
My abfence from the telefcope, juft before the 
contadt occurred, deprived me of an opportunity of 
judging whether there was any appearance of an at- 
mofphere preceding the weftern limb of Venus in 
contadt; but when Venus had entered nearly one 
half of its diameter into the Sun’s difc, my compa- 
nion and myfelf faw a luminous crefcent, which 
enlightened that part of Venus’s circumference \Vhich 
was off the Sun, fo that the whole of her circum-* 
ference was vifible, but did not continue fb until the 
internal contadt ; and at the time of the firft internal 
contadt, the eaftern or external limb of Venus Teemed 
to be united to the Sun’s limb by a black protu- 
berance or ligament, which was not broke by the 
entrance of the thread of light, till four feconds after 
that the regular circumference of Venus feemed to 
coincide with the Sun’s. 
The telefcope I made ufe of for viewing the tran- 
ftt, was a refledting one, belonging to the Philadel- 
phia Library Company, the fpeculums of which 
are 2| feet apart, and the lenfes in the eye tube 
four inches apart ; it was the leaft magnifying power 
that I ufed, as I found the tremulous motion too much 
magnified by the other power. The fmall one was 
in good order, and defined the Sun s limb, and {pots 
on its difc, very clearly. I had applied a polar axis 
VoL. LIX. H h h to 
