An opportunity being presented to revive the publishing of these Papers, which for some Moneths hath been {96} discontinued by reason of the great Mortality in _London_, where they were begun to be Printed; it hath been thought fit to embrace the same, and to make use thereof for the gratifying of the Curious, that have been pleased to think well of such Communications: To re-enter whereupon, there offers it self, first of all a Relation of an uncommon _Burning-glass_, not long since made in _France_, in the City of _Lyons_, by one called Monsieur _de Vilette_, as it was sent to the Publisher of these Tracts, in two Letters, whereof the one was in _Latine_, the other in French, to this effect. Concerning the Efficacy of Monsieur _de Villete_ his Burning Glass, all what the _P. Bertet_ hath written of it, is true. We have seen the effects of it repeated over and over again, in the Morning, at Noon, and in the Afternoon, alwaies performing very powerfully; burning or melting any Matter, very few excepted. The _Figure_ of it is round, being thirty Inches, and somewhat better in _Diameter_. On one side it hath a Frame of a Circle of Steel, to the end that it may keep its just Measure: 'Tis easie to remove it from place to place, though it be above an hundred weight, and 'tis easily put in all sorts of postures. The _burning Point_ is distant from the Centre of the Glass, about three Feet. The _Focus_ is about half a _Louys d'or_ large. One may pass ones hand through it, if it be done nimbly; for if it stay there the time of a second Minute, there is danger of receiving much hurt. _Green wood_ takes fire in it, in an instant, as do also many other Bodies. A small peice of _Pot-Iron_ was melted, and _Seconds_ ready to drop down, in 40. A _Silver Peice_ of 15 _Pence_ was pierced, in 24. A _gross Nail_ (called _le Claude paisan_) was melted, in 30. The end of a _Sword-blade_ of _Olinde_, was burn'd, in 43. A _Brass Counter_ was pierced, in 06. A piece of _red Copper_ was melted ready to drop down, in 42. {97} A peice of a _Chamber Quarry-stone_ was vitrified, and put into a Glass-drop, in 45. _Steel_, whereof Watch-makers make their springs, was found melted, in 09. A _Mineral-Stone_, such as is used in Harquebusses _a rovet_, was calcin'd and vitrified, in 1. _just._ A peice of _Morter_ was vitrified, in 52. In short, there is hardly any Body, which is not destroyed by this Fire. If one would melt it by it any great quantity of Mettal, that would require much time, the Action of Burning not being perform'd but within the bigness of the _Focus_, so that ordinarily none but small pieces are exposed to it. One Mounsieur _de Alibert_ buys it, paying for it Fifteen hundred Livers.