Emission and Transmission of Heat 



1 66 a horizontal projection, and figure 167 a section on a largei 

 scale of the lower part of the interior vessel, A B C D is a vessel 

 of tin closed at its lower end by the disc of metal E, of which the 

 manner of attachment is shown by figure 167. This vessel 



has within it a copper tube 

 bearing paddles at different 

 heights and having at its 

 lower end a horse hair brush. 

 This tube is guided by two 

 rings secured to it by the 

 rods //and /'/' and it bears 

 at its upper end a pinion 

 driven by means of the gear 

 and crank M' . 



The vessel is closed by a 

 tight cover through which 

 the central copper tube pro- 

 jects. This cover supports 

 a ring O, one centimeter 

 above the top of the tube, in 

 K which is placed a pierced 

 stopper through which pass- 

 es the stem of the thermom- 

 eter, whose reservoir is 

 nearly at the center of the vessel, and which remains fixed regardless 

 of the motion of the agitators. A' B' C D' is a second vessel 

 surrounding the first to 

 which it is fastened by 

 three glass rods F F F, 

 it is filled with cotton 

 wool and its three feet 

 are provided with screws 

 engaging in the supports 

 NN soldered to the low- 

 er vessel G G. The ves- 

 sel A' B' C D' supports 

 the crank and gear that 

 drives the pinion of the 

 central tube. Finally the 



V Fig. 166 



Fig. 165 



M 



