in Fluids. 379 



to be extremely probable, that if amber, in a very fine 

 powder, were mixed with any transparent oil, capable 

 of supporting a great degree of Heat without being 

 reduced to vapour, and exposed in it to the direct rays 

 of a very bright sun, the amber would melt and be dis- 

 solved, though perhaps very slowly. 



But if amber does not melt when exposed in water to 

 the action of the sun's beams, and consequently suffers 

 no visible change by which the existence of the Heat 

 supposed to be generated at its surface by the light can 

 be detected, ought not this Heat, were it, in fact, as in- 

 tense as it is supposed to be, to produce some visible 

 effects in the water, by which its existence would neces- 

 sarily be discovered ? 



To resolve this doubt, we must inquire what visible 

 effects it would be possible for the Heat in question to 

 produce in the water. Now if we suppose the water not 

 to be decomposed by this Heat, which, as no chemical 

 change is supposed to take place in the amber, cannot 

 happen, the only effect this Heat can possibly produce 

 on the water is an increase of its temperature, which in- 

 crease must, however, be much too small to be detected, 

 either by the feeling or by the thermometer. 



It might, perhaps, be expected that steam would be 

 found at the heated surface of the particle of amber, and 

 become visible ; but when we consider the matter for a 

 moment, we shall see that it is quite impossible that 

 such an event should happen, for even on the supposi- 

 tion (which, however, is far from being probable) that 

 the same individual particles of water which come into 

 contact with the hot surface of the amber should remain 

 in contact with it till their temperatures should gradually 

 be raised to that point at which water is changed to 



