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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 un common Burning Glass, not long since made in France, in the City of Lyons, by one called Monsieur de Villete, 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 Vilette his Burning Glass, all what the P. Bertit 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 After-noon, always 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 piece of Pot-Iron was melted, and ready to drop down, in | seconds 40. |
| A Silver Piece of 15 Pence was pierced, in | 24. |
| A gross Nail (called le Clou de paisan) was melted, in | 30. |
| The end of a Sword-blade of Olinde, was burn'd, in | 43. |
| A Brass Counter was pierced, in | 05. |
| A piece of red Copper was melted, ready to drop down, in | 42. |
