2 70 The Temperature of Water 



of the metal through the water, which remained at rest, 

 this communication would naturally have been the most 

 rapid when the metallic point was the warmest. What 

 did take place was exactly contrary to this, as we have 

 just seen. Moreover, the small thermometer, which 

 was placed close to the metallic body on one side, and 

 which in this experiment was in no degree affected by 

 the heat of this body, would not have failed to acquire 

 as much heat at least as that placed in the cork cup, which 

 was situated below the metallic body and at a greater 

 distance from it. 



The considerable amount of time which elapsed in the 

 experiments performed with the tin ball heated in boil- 

 ing water before the thermometer in the cork cup began 

 to be so sensibly affected, and the rapidity with which it 

 was then warmed through several degrees as soon as it 

 began to rise, indicate a fact which it is important to 

 notice. In order to throw light upon this fact, we 

 must consider carefully the operation of the heating of 

 cold water by the warm metallic surface with which it 

 was in contact, and examine it in its progress and in 

 all its details. 



Let us begin by supposing that the conical point of 

 the ball, at the temperature of boiling water, has just 

 been submerged vertically up to the level of its base in 

 a mass of undisturbed water at the temperature of melt- 

 ing ice. As the particles of water, which in this case 

 are in contact with the warm metallic surface, cannot 

 pass, all of a sudden, from the temperature of melting 

 ice to that of boiling water without passing through all 

 the intermediate degrees, and since these particles at the 

 temperature of melting ice cannot become warmer with- 

 out becoming more dense, it is evident that they must 



