BULK OF BODIES IN VAPOROUS CONDITION. 69 



particles, and yet you see that there is a good 

 deal of attractive force remaining behind. I 

 want now to take you another step beyond. We 

 saw that if we continued applying heat to the 

 water (as indeed happened with our piece of ice 

 here), that we did at last break up that attraction 

 which holds the liquid together, and I am about 

 to take some ether (any other liquid would do, 

 but ether makes a better experiment for my 

 purpose,) in order to illustrate what will happen 

 when this cohesion is broken up. Now this 

 liquid ether, if exposed to a very low tempera- 

 ture, will become a solid, but if we apply heat 

 to it, it becomes vapour, and I want to show 

 you the enormous bulk of the substance in this 

 new form : when we make ice into water, 

 we lessen its bulk, but when we convert water 

 into steam, we increase it to an enormous ex- 

 tent. You see it is very clear that as I apply 

 heat to the liquid I diminish its attraction of 

 cohesion it is now boiling, and I will set fire 

 to the vapour, so that you may be enabled to 

 judge of the space occupied by the ether in this 

 form by the size of its flame, and you now see 

 what an enormously bulky flame I get from 

 that small volume of ether below. The heat 



F 3 



