334 Of th e Propagation of Heat 



DESCRIPTION OF THE PLATES. 



PLATE I. 



THIS Plate represents the cylindrical Passage Ther- 

 mometer used in the experiments on the conduct- 

 ing power of liquids with regard to Heat. 



Fig. i. a, by is a section of the brass tube in which 

 the Thermometer c, with an oblong copper bulb, is 

 placed. 



e, f y is the glass tube of the thermometer, which, for 

 want of room in the Plate, is represented as broken off 

 at/. 



g y is a stopple of cork by which the end of the brass 

 tube, <z, b t is closed ; and 



h, is a circular disk of the same substance. 



The space in the brass tube below this disk h, sur- 

 rounding the bulb of the thermometer, was occupied 

 by the liquid whose conducting power was determined. 

 The space between the disk and the cork-stopper g, was 

 rilled with eider-down. 



Between the inside of the brass tube and the lower 

 part of the bulb of the thermometer are seen the 

 wooden pins which served to confine the thermometer 

 in its place. 



Fig. 2. This is an horizontal section of the brass 

 tube, and a bird's-eye view of the thermometer in its 

 place. 



PLATE II. 



Fig. 3. This Figure shows the manner in which the 

 experiments were made, in which a cake of ice at the 



