.ft ART OF MAKING GUN-FLINTS. 



and is the principal reafon of their much fpeedier augmentation 

 of temperature in this way. The extrication and afcent of 

 elaftic fluid appears, in moil and probably in all cafes, to pre* 

 cede, and at laft to produce circulation in denfe fluids. And on 

 this objeci there is flill an extenfive field for refearch, con- 

 cerning the manner in which heat is communicated through 

 fluids. But it would be by no means fair to anticipate,- by- 

 crude conjecture, thofe explanations which we may expect to 

 obtain from the experimental refearch of others. W. N. 



II. 



A Memoir on the Art of making Gun-Flints. By Citizen 

 Dolomieu. * 



No information X HE art of making gun-flints, which has been long prac- 

 books on "thwart *^ e< * * n a ^ ma ^ terr i torv fituated between the two neighbour- 

 of making gun- ing departments of Loir-Cher, and I/Indre, is directed to an 

 s * object, of which the whole value, commercially confidered, 



is of little magnitude ; but which is of the firft neceflity in the 

 ufe of fire-arms of every defcription. The author of the pre-* 

 fent Memoir was defirous of acquiring fome information re- 

 fpe&ing it, but found that it was to no purpofe that he 

 extended his refearches to a variety of works on mineralogy 

 and different fubjefts of the arts and trade. The Encyclo- 

 pedic is filent on this procefs ; excepting in the repetition o( 

 a ridiculous prejudice concerning the re-prod u<5tion of flints 

 in places whence they were excavated. From the precision 

 with which the figure is given to thefe flones, it has even 

 been fufpe&ed that they could hardly be afforded at the low 

 price they bear, if in its firft flate the material were not even 

 foft. But the art is extremely fimple in its procefs; it re- 

 quires a very fmall number of inflruments, a fliort apprentice- 

 fhip, and a very moderate degree of fkill to form, by mere 

 frafture, figures fo accurate, faces fo fmooth, outlines fo 

 direct, and angles fo neat, that the flone feems as if cut on 

 the wheel of the lapidary. Five or fix fmall blows of the 

 hammer, during one minute of time, are fufflcient to produce 



* From Mcmoires de rinftitute National IIJ, 348, in part 

 abridged, 



the 



