in variozts Substances. 



449 



seen In the following table; and in order that it may be 

 compared with those made with the same quantity of 

 silk differently disposed of, I have placed those experi- 

 ments by the side of it : — 



It is not a little remarkable, that, though the cover- 

 ing formed of sewing-silk wound round the bulb of the 

 thermometer in the 19th experiment appeared to have 

 so little power of confining the Heat when the instru- 

 ment was very hot, or when it was first plunged into the 

 ice and water, yet afterwards, when the Heat of the 

 thermometer approached much nearer to that of the sur- 

 rounding medium, its power of confining the Heat 

 which remained in the bulb of the thermometer appeared 

 to be even greater than that of the silk in the experiment 

 No. 15, the time of cooling from 20° to 10° being in the 

 one 399'^ and in the other 342'". The same appearance 

 was observed in the following experiments, in which the 

 bulb of the thermometer was surrounded by threads of 

 wooly of cotton^ and of linen^ or flax, wound round it, in 



