SOLID, LIQUID, AND GASEOUS STATE. 61 



because it will serve as a convenient source of 

 heat [placing the red-hot iron in the centre of 

 the block of ice]. You see I am now melting 

 the ice where the iron touches it. You see the 

 iron sinking into it, and while part of the solid 

 water is becoming liquid, the heat of the ball 

 is rapidly going off. A certain part of the 

 water is actually rising in steam the attraction 

 of some of the particles is so much diminished 

 that they cannot even hold together in the 

 liquid form, but escape as vapour. At the same 

 time you see I cannot melt all this ice by the 

 heat contained in this ball. In the course of a 

 very short time I shall find it will have become 

 quite cold. 



Here is the water which we have produced 

 by destroying some of the attraction which 

 existed between the particles of the ice, for 

 below a certain temperature the particles of 

 water increase in their mutual attraction and 

 become ice; and above a certain temperature 

 the attraction decreases and the water becomes 

 steam. And exactly the same thing happens 

 with platinum, and nearly every substance in 

 nature; if the temperature is increased to a 

 certain point it becomes liquid, and a further 



