264 The Temperature of Water 



seconds when the mercury in the thermometer began to 

 rise, and in 3 minutes it had risen three degrees and 

 a half, namely, from 32 to 35^; when 5 minutes had 

 elapsed it had risen to 36. 



Another small thermometer placed just below the 

 surface of the ice-cold water, and only T 2 Q- of an inch from 

 the upper part of the conical point and on one side of 

 it, did not appear to be sensibly affected by the vicinity 

 of that warm body. 



A third thermometer, the bulb of which was placed 

 in the brass cup just on the outside of the cork cup and 

 on a level with its brim, showed that the water which 

 immediately surrounded the cork cup remained con- 

 stantly at the temperature of freezing during the whole 

 time that the experiment lasted. 



As I well knew from the results of the experiments 

 on the propagation of heat in a solid bar of metal,* that 

 no one of the particles of cold water in contact with the 

 surface of the conical projection, in the experiment which 

 I have just described, could acquire by this momentary 

 contact a temperature as high as that of the warm metal, 

 I was by no means surprised to find that the thermom- 

 eter belonging to the cork cup rose no higher than 36. 



In order to see if it could not be made to rise not 

 only higher, but also more rapidly, by employing the 

 metallic ball heated to such a temperature as it might be 

 supposed would be sufficient to heat those particles of 

 ice-cold water which should come into contact with its 

 conical point, to the temperature at which the density 

 of water is supposed to be a maximum, I made the 

 following experiment. 



* An account of these experiments has been given in a memoir presented to the 

 Mathematical and Physical Class of the National Institute of France, on the yth of 

 May, 1804. See also p. 144. 



