20 ART OP MAKING GUW-FLT 1 



trie3 are entirely deprived of them ; and the author thinks 

 that it may probably be affirmed, that France altnoft alone 

 poiieflfes that variety of filex which can be eafily broken into 

 gun-flints, iince he cannot fuppofe that the art of making 

 them could remain a myftery to other nations who do not 

 practice it, though they make great ufe of the flints : the. art 

 itfelf being fo fimple, that they muft; have fpecdily acquired 

 it, if they have pollefled the material. 



©•nomination. In his defcription of the variety of filex here alluded to, he 

 gives it the name of filex pyromachus to exprefs its ufe, 

 which he prefers to the term filex fclopetarius, as being more 

 mulical. 



The external characters are : 



External charac- The lilex pyromachus, when dug up, is always covered 

 with a white, external cruft, one or two lines or more in 

 thicknefs, of an earthy, chalky appearance, and loofc texture, 

 much fofter and lefs heavy than the filex it envelopes. The 

 external form, of the malles of good ftones of this defcription 

 has a fomewhat convex furface, approaching to the globular 

 figure. Thofe of irregular forms are full of imperfections. 

 The beft ft ones are not very large. They feldom exceed the 

 weight of twenty pounds, and they ought not to be of lefs 

 weight than one or two pounds. Their afpect, when broken, 

 is greafy, mining a little, and the grain is fo fine, that it is 

 imperceptible. The colour of thefe good ftones may vary 

 from the yellow colour of honey to a blackifh brown. In this 

 refpect it is to be noted that the value of a ftone does not de- 

 pend on its colour, but on the uniformity of the tint, which 

 becomes lefs intenfe when the ftone is reduced into thin 

 fplinters. The flints of the two departments firft mentioned 

 are yellowifh. Thofe of the chalk hills on the banks of the 

 Seine are blackifh brown. Both the one and the other, when 

 pulverifed, are perfectly white. The filex pyromachus ought 

 to poflefs an uniform femi-tranfparence, of a greafy afpecl, 

 to fuch a degree, as to admit letters to be diftinguifhed 

 through a piece of the ftone of one-fiftieth of an inch thick, 

 laid clofe upon the paper. Its fracture muft be fmooth and 

 equal throughout, and very flightly conchoidal ; that is to 

 fay, convex or concave. This kind of fraclure is one of the 

 rooft efifential properties upon which the faculty of being divided 

 into gun-flints depends. 



The 



