The _First_ regardeth the excellency of the long _Telescopes_, made by the said _Campani_, who pretends to have found a way to work great _Optick Glasses_ with a Turne-tool, without any Mould: And whereas hitherto it hath been found by Experience, that _small_ Glasses are in proportion better to see with, upon the Earth, than the _great_ ones; that Author affirms, that his are equally good for the Earth, and for making Observations in the Heavens. Besides, he useth three Eye-Glasses for his great _Telescopes_, without finding any _Iris_, or such Rain-bow colours, as do usually appear in ordinary Glasses, and prove an impediment to Observations. The _Second_, concerns the _Circle of Saturn_, in which he hath observed nothing, but what confirms Monsieur _Christian Huygens de Zulichem_ his Systeme of that Planet, published by that worthy Gentleman in the year, 1659. {3} The _Third_, respects _Jupiter_, wherein _Campani_ affirms he hath observed by the goodness of his Glasses, certain _protuberancies_ and _inequalities_, much greater than those that have been seen therein hitherto. He addeth, that he is now observing, whether those sallies in the said _Planet_ do not change their scituation, which if they should be found to do, he judgeth, that _Jupiter_ might then be said to turn upon his _Axe_; which, in his opinion, would serve much to confirm the opinion of _Copernicus_. Besides this, he affirms, he hath remarked in the _Belts_ of _Jupiter_, the shaddows of his _satellites_, and followed them, and at length seen them emerge out of his Disk. * * * * * _A Spot in one of the Belts of Jupiter._ The Ingenious Mr. _Hook_ did, some moneths since, intimate to a friend of his, that he had, with an excellent twelve foot Telescope, observed, some days before, he than spoke of it, (_videl._ on the ninth of _May_, 1664, about 9 of the clock at night) a small Spot in the biggest of the 3 obscurer _Belts_ of _Jupiter_, and that, observing it from time to time, he found, that within 2 hours after, the said Spot had moved from East to West, about half the length of the Diameter of _Jupiter_. * * * * * _The Motion of the late Comet praedicted._