336 PHILOSOPHICAL TRANSACTIONS. [anNO IJSQ. 



where in the room the least sign of water, tliough he looked carefully for it, 

 and had put a pint into the digester, save only that the fire was quite extin- 

 guished, and every coal belonging to it was black in an instant. 



But to confirm the elasticity of water, or to show, at least, that there is a 

 much stronger elastic force in water and air, when jointly included in a vessel 

 than when air alone is inclosed, he made the following experiment: he took 

 two §vj phials, into the one he put about §v of water, or better, and so corked 

 it as well as possible; the other he corked in the same manner, without putting 

 any thing into it. He inclosed them both in his new digester, four-fifths being 

 filled with water; when the heat was raised to about five seconds, he heard a 

 considerable explosion, and a jingling of glass within the vessel, and shortly 

 after another explosion, but not so loud as the former; whence he concluded, 

 that both the phials were broken. He then let the digester cool leisurely, and 

 the next day he opened it; both the corks were swimming on the top of the 

 water, but only one of the phials was broken, viz. that one into which he had 

 not put the water. 



Again, having had some very strong phials made, to make some peculiar 

 experiments, he took one of them, and having filled it about a quarter full 

 with water, and corked it very well, he set it in a square iron frame, with a screw 

 to keep down the cork, and keep it from flying out. He then put it into a 

 digester, four-fifths filled with water; which being heated to a due height; 

 when opened, he found the cork forced into the phial, though the cork was so 

 very large, that it amazed several who saw it, to conceive how it was possible 

 for so large a cork to be forced into the bottle. Hence it manifestly appears, 

 that the pressure in the digester, in which was proportionally more water, and 

 less air, was stronger than the pressure within the phial, in which was propor- 

 tionally more air and less water. 



Then Mr.C. reasoned thusalsoof the two former phials : thattheair in the phial, 

 in which was included no water, making not a proportionate resistance to the 

 ambient pressure in the digester, in which was a considerable quantity of water, 

 the cork was forced inward with such violence, that it, together with the water, 

 dashed the phial in pieces; but that in the other phial, in which there were five- 

 sixths of water, the inward pressure in the phial being greater than the ambient 

 pressure in the digester, in which were only four-fifths of water, the cork was 

 forced outward ; and that the small difference between the proportionate quan- 

 tity of water and air in the phial and in the digester, being only as four-fifths 

 to five-sixths, was the reason, not only why the bottle was not broken, but 

 also of the faintness of the explosion. 



