Page:Philosophical Transactions

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the planet presently became distinct, and her limb well defined. Upon this, I applyed myself to observe the passage of the Sun's and Venus's preceding limbs, by the vertical, and of their lower limbs by the horizontal, wires in the reflector, and made the following observations; one of my assistants counting the clock, and the other writing down the observations as I made them; which, having made the proper correction of the time for the change of the Sun's declination, stand as follows.

	True time.				diff. long. ⊙ & ♀		♀ Lat. South.
	^h	,	,,		,	,,	,	,,
At	4	21	20	Sun at the vertical			10	47
			31	Venus at the same	9	2
		23	6	Venus at the horizontal	9	4	10	50
		24	23	Sun at the same
		27	29	Venus at the horizontal	9	25	10	52
		28	47	Sun at the same
		35	15	Sun at the vertical			10	55
			21	Venus at the same	9	56
		37	49	Venus at the horizontal	10	8	11	00
		39	9	Sun at the same

As Venus began now to draw near the Sun's limb, I prepared to observe her egress. The interior contact did not appear so perfectly instantaneous, as Dr. Halley's papers led me to expect. I was not certain of it till 4^h 47′ 21″, though I doubted of it at 17″. The exterior contact I judged to be at 5^h 5′ 49″, doubtful also 3 or 4″; and so the passage of Venus's diameter, 18′ 28″.

The above observations gave me several altitudes and azimuths of Venus, from whence I deduced her

Vol. LIV.

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right

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