III. 



CURIOSITIES OF HEAT CONDUCTION, 

 i. A Vessel too Hot to boil Water. 



IF a saucepan in which water is boiling on 

 the fire be emptied, and a few fresh drops of 

 cold water put into it, the heat of the pan 

 quickly dries up the water that is, converts 

 it into steam or vapour. If, then, the pan be 

 kept on the fire till it is much hotter than when 

 it had the boiling water in it till it is, in fact, 

 red hot and when it is in that condition a few 

 drops of cold water are put into it, we might 

 expect that they would flash into steam in- 

 stantaneously. 



At this point, however, it is well to remem- 

 ber that an objection will be lodged by the 

 kitchen authorities to a proceeding which in- 

 volves making a saucepan red-hot, an objection 

 which is likely to be sustained, on appeal, by 

 the higher court. We had better begin, then, 

 from the beginning, with a professedly scientific 

 piece of apparatus. 



The vessel for the experiment may be a 

 small dished plate, of section such as is shown 

 in Fig. 36 at A. It should be of good conduct- 

 ing metal, silver or copper (it is less liable to get 

 lost when left lying about if of copper), and 



152 



