PARTS OF ANIMALS, II. ii. 



A is said to be " hotter " than B (1) if that which 

 comes into contact with it is heated more by it than 

 by B. (2) If it produces a more violent sensation 

 M'hen touched, and especially if the sensation is 

 accompanied by pain. (The latter is not always a 

 true indication, since sometimes the pain is due to the 

 condition of the percipient.) (3) If it is a better 

 melting or burning agent. (4) If it is of the same 

 composition as B, but greater in bulk,'^ it is said to be 

 "hotter" than B, and in addition (5) if it cools 

 more slowly than B, or warms up more quickly : in 

 both these cases we call the thing " hotter " in its 

 nature — as we call one thing " contrary " to another 

 when it is far removed from it, and " like " it when 

 it is near it. But although the senses in which 

 one thing is said to be " hotter " than another 

 are certainly as many as this, if not more, yet 

 no one thing can be " hotter " in all of these 

 ways at once. For instance, boiling water can im- 

 part heat more effectively than flame ; but flame 

 is able to cause burning and melting, whereas 

 water is not. Again, boiling water is hotter than 

 a small fire, but the hot water will cool off more 

 quickly and more thoroughly than the small fire, 

 since fire does not become cold, but all water 

 does. Again, boiling water is hotter to the touch 

 than oil, yet it cools and solidifies more quickly. And 

 again, blood is warmer to the touch than either water 

 or oil, yet it congeals more quickly. Again, stone 

 and iron and such substances get hot more slowly 

 than water, but once they are hot they burn other 

 things more than water can. In addition to all this 

 there is another distinction to be made among the 

 things that are called " hot " : in some of them the 



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