The Propagation of Heat 



195 



EXPERIMENT 73. Procure two small tinned iron 

 vessels, such, as the cans in which condensed milk, 

 treacle, and such commodities are frequently packed 

 for sale. Remove all paper from the outside of each. 

 By holding one of the cans in the upper part of a candle 

 or luminous gas flame, cover the bottom with a layer 

 of soot, or as it is sometimes termed, lampblack. 



/ \ 



Fig. 60. 



Support the two vessels on the top of a large iron plate 

 provided with iron supports, by putting pipeclay 

 triangles under the cans as indicated in the figure. 

 Arrange the triangles so that the distances from the 

 cans to the plate are equal. Under the plate place 

 a good Bunsen burner, making the distances of the 

 bottoms of the cans from the burner as nearly equal 

 as may be. To prevent uneven heating through 

 draughts, the conical top shown in the diagram may 



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