of the progress of the Studies, Labours, and attempts of the Curious and learned in things of this kind, as of their compleat Discoveries and performances: To the end, that such Productions being clearly and truly communicated, desires after solid and usefull knowledge may be further entertained, ingenious Endeavours and Undertakings cherished, and those, addicted to and conversant in such matters, may be invited and encouraged to search, try, and find out new things, impart their knowledge to one another, and contribute what they can to the Grand design of improving Natural knowledge, and perfecting all Philosophical Arts, and Sciences. All for the Glory of God, the Honour and Advantage of these Kingdoms, and the Universal Good of Mankind.
An Accompt of the improvement of Optick Glasses.
There came lately from Paris a Relation, concerning the Improvement of Optick Glasses, not long since attempted at Rome by Signor Giuseppe Campani, and by him discoursed of, in a Book Entituled, Ragguaglio di nuoue Oss}ervationi, lately printed in the said City, but not yet transmitted into these parts; wherein these following particulars, according to the Intelligence, which was sent hither, are contained.
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.