128 KISTOUV OF 



From hence, therefore, we may be very certain of the cold 

 dilating the water; and experience also shows, that the force 

 of this expansion has been found as great as any which heat has 

 been found to produce. The touch-hole of a strotig gun-barrel 

 being stopped, and a plug of iron forcibly driven into the muzzle, 

 after the barrel had been filled with water, it was placed in a 

 mixture of ice and salt ; the plug, though soldered to the barrel^ 

 iit first gave way, but being fixed in more firmly, within a quar- 

 ter of an hour the gun-barrel burst with a loud noise, and blew 

 up the cover of the box wherein it lay. Such is its force in an 

 ordinary experiment. But it has been known to burst cannons, 

 filled with water, and then left to freeze ; for the cold congealing 

 the water, and the ice swelling, it became irresistible. The 

 bursting of rocks by frost, which is frequent in the northern 

 climates, and is sometimes^ seen in our own, is an equal proof 

 of the expansion of congealed water. For having by some 

 means insinuated itself into the body of the rock, it has remain- 

 ed there till the cold was sufficient to eflfect it by congelation. 

 But when once frozen, no obstacle is able to confine it from 

 dilating ; and, if it cannot otherwise find room, the ruck must 

 burst asunder 



This alteration in the balk of water might have served as a 

 proof tliat it was capable of being compressed into a narrower 

 space than it occupied before ; but, till of late, water was held 

 to be incompressible. The general opinion was, that no art 

 whatsoever could squeeze it into a narrower compass ; that no 

 power on earth, for instance, could force a pint of water into a 

 vessel that held an hair's-breadth less than a pint. And this, 

 said they, appears from the famous Florentine experiment; 

 whei-e the M'ater, rather than suffer a compressure, was seen to 

 ooze through the pores of the solid metal ; and, at length, mak 

 ing a cleft in the side, spun out with great vehemence. But 

 later trials have proved that water is very compressible, and 

 partakes of that elasticity which every other body possesses in 

 some degree. Indeed, had not mankind been dazzled by the 

 brilliancy of one inconclusive experiment, there were numerous 

 reasons to convince them of its having the same properties with 

 other substances. Ice, which is water in another state, is very 

 elastic. A stone, flung slantingly along the surface of a pond, 

 bounds from the water several times ; which shows it to he 



