* * * * * 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 conveigh 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 wondred at by those, {120} 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 accompt 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;