112 On the Powers of Steam, &c. 



tinued to heat their kettles with as much facility as 

 if they had studied all their lives under that ingenious 

 professor. 



To throw cold water upon a hot stove, in order to 

 make it heat any thing more quickly, seemed, at first 

 view, not a little extraordinary ; but, upon consider- 

 ing the matter a little more attentively, I immediately 

 perceived, that this was perfectly consonant to the 

 doctrines of heat, delivered by Professor Black, and 

 that it was even one of the strongest illustrations of 

 them. Although the operation is, in itself, perfectly 

 simple, yet, in order to make the following observa- 

 tions more clearly understood, it may not be amiss 

 to give a circumstantial description of it, particularly 

 for the benefit of those who have not seen it per- 

 formed. 



It succeeds best with a stove which is not perfectly 

 smooth and even, because the water has an opportu- 

 nity of lodging between the inequalities, and is not 

 so soon dissipated by the heat of the stove. Two 

 or three spoonfuls of water, either hot or cold, being 

 thrown on the top of the stove, the kettle of water is 

 instantly placed upon it, whilst it is hissing or bub- 

 bling up. 



As soon as the steam of this water strikes against 

 the bottom of the kettle, it is immediately condensed, 

 and, at the same instant, a large quantity of heat 

 emerges from it, and passes into the kettle of water, 

 where its effects are quickly perceived. The steam, 



