in Fluids. 251 



in consequence of the passage of the Heat through the 

 medium by which the thermometer is surrounded, the 

 conducting power of that medium is shewn by the quick- 

 ness of the ascent or descent of the thermometer, when, 

 having been previously brought to a certain temperature, 

 the instrument is suddenly removed and plunged into 

 another medium at any other constant given temperature. 



Having still fresh in my memory the accidents I had 

 so often met with in eating hot apple-pies, I was very 

 impatient, when I had completed this instrument, to see 

 if apples, which, as I well knew, are composed almost 

 entirely of water, really possess a greater power of retain- 

 ing Heat than that liquid when it is pure or unmixed 

 with other bodies. But before I made the experiment, 

 in order that its result might be the more satisfactory, I 

 determined in the following manner how much water 

 there really is in apples, and what proportion their fi- 

 brous parts bear to their whole volume. 



960 grains of stewed apples (the apples having been 

 carefully pared and freed from their stems and seeds be- 

 fore they were stewed) were well washed in a large quan- 

 tity of cold spring water, and the fibrous parts of the 

 apples being suffered to subside to the bottom of the 

 vessel, the clear part of the liquor was poured off", and 

 the fibrous remainder being thoroughly dried was carefully 

 weighed, and was found to weigh just 25 grains. 



This fibrous remainder of the 960 grains of stewed 

 apples being again washed in a fresh quantity of cold 

 spring water, and afterwards very thoroughly dried by 

 being exposed several days on a china plate placed on the 

 top of a German stove, which was kept constantly hot, 

 was again weighed, and was found to weigh no more than 

 i8j\ grains. 



