Fire-places and Kitchen Utensils. 329 



temperature, which, under the existing circumstances, 

 was impossible ; for, as the door of the oven was left 

 open, the upper surface of the water was continually 

 cooled by giving off heat to the cold atmosphere, which, 

 rushing into the oven, came into contact with it ; and, 

 as soon as the water was made boiling hot, an internal 

 motion of another kind was produced in it, in conse- 

 quence of the formation and escape of the steam, which 

 last motion was likewise rapid and violent in propor- 

 tion to the rapidity of the communication of heat. 

 Hence we see that the water in the copper stewpan 

 must have been in a state of continual agitation from 

 the time it went into the oven till it came out of it ; 

 and the state in which this liquid was found at the end 

 of the experiment was precisely that which might have 

 been expected, on a supposition that these motions 

 would take place. Let us now see what, agreeably 

 to our assumed principles, ought to have taken place 

 in the other stewpan. 



In this case, its contents having been nearly boiling 

 hot when the stewpan was put into the oven, and the 

 door of the oven having been kept closed, and the stew- 

 pan covered with its earthen cover, and the stewpan 

 being moreover earthen-ware, which substance is a very 

 bad conductor of heat, and being placed not immedi- 

 ately on the bottom of the oven, but on a thick tile, 

 every circumstance was highly favourable not only for 

 keeping up the equal heat of the water, but also for 

 preventing it from receiving additional heat so rapidly 

 as to agitate it by boiling. There is therefore every 

 reason to think that the water remained at rest, or 

 nearly so, during the whole time it was in the oven ; 

 and the transparency of this fluid at the end of the 



