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An Extract
To give you some account of my present Studies, I shall acquaint you, that having been a good while very assiduous and' careful in making Observations of Venus, to see, whether that Planet did not turn about its Axis, by a motion like to that of Jupiter and Mars; I met at first with many difficulties, but at last considering, that I should succeed better in my Observations at a time when Venus is at a good distance from the Earth, than when she is near thereto, I attentively observ'd, when she was risen somewhat high above the Horizon, and shin'd brighter, whether I could not discern in her some part remarkable either by its brightness or obscurity, among the rest, especially about the middle of her Disk. And this I did not in vain; for I discover'd at last towards the middle of her Body a part clearer than the rest, by which one might judge of the Motion of the Rest of this Planet.
The first time I saw it, was October 14. 1666. h. 5. 45. p.m. and then this bright part was very near the Center, on the North side. And at the same time I observed Westward two obscure spots, somewhat oblong; but I could not then see that resplendent part
long enough to conclude any thing from thence, not was I able to see any thing well of those parts till April 28. 1667. on which day, a quarter of an hour before Sun-rising, I saw again a bright part, scituated near the Section, and distant from the Southern Horn a little more than ¼ of its Diameter. And near the Eastern Ring I saw a dark and somewhat oblong spot, which was nearer to the Northern than the Southern Horn. At the rising of the Sun I perceived, that this bright part was then no more so near the Southern Horn, but distant from it ⅓ of its Diameter. This gave me great satisfaction. But
