Page:Philosophical Transactions - Volume 001.djvu/76

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he thought, that he saw also the Light continued from without, although very slender. But he acknowledges, that he could never yet precisely determine, by how much the largeness of the Ring was bigger than the Diameter of Saturn's Body. As for the proportion of the Length to the Breadth, he affirms, to have alwaies estimated it to be two and a half, or very neer so; and to have found in his Observations, that in January last, one time, the length of Saturn was 12 Lines, and the breadth 5. Another time, the length was 12. Lines, and the breadth 4. and this by a peculiar method of his own. But yet he acknowledges also, that sometimes he hath estimated it as 7, to 3. and at other times as 13. to 5. and that if there do not happen a change in the magnitude of the Ring (as it is not likely there does) that must needs proceed from the Constitution of the air, or of the Glass's having more or less Aperture, or from the difficulty of making an exact estimate of their proportions. However it is not much wide (saith he) of two and an half, although Campani make the length of the Ring but double to its breadth.

Monsieur Auzout believes, that he was one of the first that have well observed this shadow of Saturn’s Body upon its Rings which he affirms happened two years since; when, observing in July, for the first time, with a Telescope of 21. and then another of 27. foot, he perceived, that the Angle of the obscure space on the right side beneath, was bigger and wider, than the three other Angles, and that some interruption appear'd there, between the Ring, and the Body of Saturn; of which he saith to have given notice from that time to all his friends, and in particular, as soon as conveniently he could, to Monsieur Hugens.

He confesseth, that he hath not had the opportunity of observing Saturn in his Oriental Quadrat; yet he doubts not, but that the shadow appears on the Left-side, considering, that the Existence of the Ring can be no longer doubted of, after so many Observations of the shadow cast by Saturn’s Body upon it, according as it must happen, following that Hypothesis; there being no reason, why it should cast the said shadow on one side, and not on the other.

Concerning the Observation of Jupiter and its satellites, the famous Astronomer of Bononia, Cassinus, having pub-