|A piece of Chamber Quarry-stone was vitrified, and put into a Glass-drop, in||45.|
|Steel, where of Watch-makers make their springs, was found melted, in||09.|
|A Mineral-stone, such as is used in Harquebusses à Rouët, was calcin'd and vitrified, in||1. just.|
|A Piece of Morter was vitrified, in||52.|
In those, there is hardly any Body, which is not destroyed by this Fire. If one would melt by it any great quantity of Metal, 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 Monsieur d'Alibert buys it, paying for it Fifteen hundred Livres.
Since this Information, there were, upon occasion given from hence, upon the same subject, further communicated from Paris the following Particulars:
I see by two of the Letters, that you incline to believe, the Glasses of Maginus and Septalius do approach to that of Lyons: But I can assure you, they come very far short of it. You may consult Maginus his Book, where he describes his; and there are some Persons here that have seen one of his best, which had but about twenty Inches diameter; so that this of Lyons must perform at least twice as much. As to Septalius, we expect the Relations of it from Intelligent and Impartial Men. It cannot well be compared to that of Lyons, but in bigness; and in this case, if it have five Palms (as you say) that would be about 31 feet French, and so it were a Foot bigger, which would make it half as much greater in surface: But as to the Effects, seeing it burns so far off; they cannot be very violent. And I have heard one say, that had seen it, that it did not set Wood on Fire but after the time of saying a Miserere. You may judge of the difference of the Effects, since that of Lyons gathers its Beams together within the space of seven or eight Lines;