THE BOILING POT 219 



and thrusts in all directions to remove the obstacles 

 that oppose its expansion. However solid it may 

 be, the pot ends by bursting under the indomitable 

 pushing of the imprisoned steam. That is what I 

 am going to show you with a little bottle, and not 

 with a pot, which would not shut tight enough and 

 the cover of which could be easily pushed off by the 

 steam. And besides, even if I had a suitable pot, I 

 should take care not to use it, for it might blow the 

 house up and kill us all." 



Uncle Paul took a glass vial, put a finger's breadth 

 of water into it, corked it tightly with a cork stop- 

 per, and then tied the cork with a piece of wire. The 

 vial thus prepared was put on the ashes before the 

 lire. Tln-n he took Emile, Jules, and Claire, and 

 <hvw them (jniekly into the garden, to see from a 

 distance what would happen, without fear of being 

 injured by the explosion. They waited a few min- 

 utes, then boom! They ran up and found the vial 

 broken into a thousand pieces scattered here and 

 the iv with extreme violence. 



"The cause of the explosion and the bursting of 

 the bottle was the steam, which, having no way of 

 escape, accumulated and exerted against its prison 

 walls a stronger and stronger pressure as the tem- 

 '11 re rose. A time then came when the vial 

 could no longer resist the pressure of the steam, and 

 it burst to pieces. They call elastic force the pres- 

 sure exerted by steam on the inside of pots that hold 

 it prisoner. The greater the he,-it, the stronger the 

 pressure. With heat enough it may acquire an irre- 

 sistiblc power, capable of luii-ting, not only a glass 



