MODIFIED by COMPRESSION. 79 



ous particulars, to fleer between the oppofite faults of prolixity 

 and barrennefs. My object Shall be to defcribe, as fhortly as 

 pofllble, all the methods followed, fo as to enable any chemifl 

 to repeat the experiments ; and to dwell particularly on fuch 

 circuraftances only, as feem to lead to conclusions of import- 

 ance. 



The refult being already known, I confider the account I am 

 about to give of the execution of thefe experiments, as addref- 

 fed to thofe who take a particular interefl in the progrefs of 

 chemical operations : in the eyes of fuch gentlemen, I truft, 

 that none of the details into which I muft enter, will appear fu~ 

 perfluous. 



II. 



Principle of execution upon which the following Experiments were con- 

 dueled. — Experiments with Gun-Barrels filled with baked Clay, and 

 welded at the muzzle. — Method with the Fufible Metal. — Remarkable 

 effebls of its expanfion. — NeceJJity of introducing Air. — Refults ob- 

 tained. 



When I firft undertook to make experiments with heat 

 acting under compreflion, I employed myfelf in contriving 

 various devices of fcrews, of bolts, and of lids, fo adjust- 

 ed, I hoped, as to confine all elaltic fubftances ; and per- 

 haps fome of them might have anfwered. But I laid afide 

 all fuch devices, in favour of one which occurred to me in 

 January 1798 ; which, by its Simplicity, was of eafy appli- 

 cation in all cafes, and accomplished all that could be done 

 by any device, Since it fecured perfect Strength and tightnefs to 

 :he utmoSl that the veSTels employed could bear, whether form- 

 id of metallic or earthy fubStance. The device depends upon 



the 



