Of Monsieur de Sons Progress in Working Parabolar Glasses

PHILOSOPHICAL TRANSACTIONS. Monday, Decemb. 4. 1665. The Contents. Monsieur de Sons progress in working Parabolar Glasses. Some speculations of Monsieur Auzout concerning the changes, likely to be discovered in the Moon. The instance of the same Person to Mr. Hook, for communicating his contrivance of making with Glasses of a few feet Diameter, Telescopes drawing several hundred feet; together with his offer of recompensing that secret with another, which teaches, How to measure with a Telescope the Distances of Objects upon the Earth. The Experiment of Kircher, of preparing a Liquor, that shall sink into, and colour the whole Body of Marble, delivered at length. An Intimation of a Way found in Europe, to make good China-Dishes. An Account of an odd Spring in Westphalia, together with an Information touching Salt-Springs; and a way of straining Salt-water. Of the Rise and Attempts of a way to convey Liquors immediately into the Mass of Blood. Of Monsieur de Sons Progress in working Parabolar Glasses. Since what was mentioned in the immediately precedent Tract, touching Monsieur de Son's noble attempt of grinding Glasses of a Parabolical Figure, the Publisher of these Papers hath himself seen two Eye-glasses of that shape, about one inch & a half deep, and one inch and a quarter broad, wrought by this Eminent Artist with a rare Steel-instrument of his own contrivance and workmanship, and by himself also polished to admiration. And certainly it will be wondered at by those, who who shall see these Glasses, how they could be truly wrought to such a Figure, with such a Cavity; & yet more, when they shall hear the Author undertake to excavate other such Eye-Glasses to above two inches, and Object-glasses of five inches Diameter. He hath likewise already begun his Object-glasses for the mentioned two Ocular ones, of the same Figure of about two inches Diameter, which are to be left all open, yet without causing any colours. Of all which 'tis hoped, that shortly a fuller and more particular account will be given. Monsieur Auzout's Speculations of the Changes, likely to be discovered in the Earth and Moon, by their respective Inhabitants. This Inquisitive Philosopher in a letter of his, lately written to his correspondent in London, takes occasion to discourse of his considerations concerning those Changes, mentioned in the Title, as followes: I have (faith he) sometimes thought upon the Changes, which 'tis likely, the supposed Inhabitants of the Moon might discover in our Earth, to see, whither reciprocally I could observe any such in the Moon. For example, methinks, that the Earth would to the people of the Moon appear to have a different face in the several seasons of the year; and to have another appearance in Winter, when there is almost nothing green in a very great part of the Earth; when there are Countries all covered with snow, others, all covered with water, others, all obscured with Clouds, and that for many weeks together: Another in Spring, when the Forrests and Fields are green. Another in Summer, when whole Fields are yellow &c. Methinks, I say, that these changes are considerable enough in the force of the reflexions of Light to be observed, since we see so many differences of Lights in the Moon. We have Rivers considerable enough to be seen, and they enter far enough into