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Mr. G. F. Rodwell on the Effect of Heat on 



Table showing approccimately the Action of Heat on the Chloride, Bromide, 

 and Iodide of Silver, between —60° C. and 750° C. 



Temperatures. 



The bromide fuses to a reddish brown liquid, not unlike bromine, and 

 it solidifies to a bright yellow transparent solid when seen in thin layers. 

 In thick layers it appears to be brownish yellow. It is brittle even before 

 it is quite cold. During the process of cooling loud cracking noises, like 

 the cracking of a piece of porcelain or thick glass, are produced. The 

 solidified solid produces a metallic ring when struck ; but this is less 

 marked than in the case of the chloride of silver. 



5. Effects of Heat on the Chloride of Silver. 



Precipitated chloride of silver was fused and cast in warm glass tubes. 

 It had been very carefully prepared in the dark, and the fused mass in 

 thin layers was colourless and quite transparent. When warm, a rod of 

 the chloride was very flexible, and to some extent malleable ; when cold 

 the bar did not bend without fracture, and repeated fusings seemed to 

 render it more liable to fracture. The rod contracted a good deal on 

 cooling, and easily came out of the tube in which it was cast. Bods of 

 6 inches long by 5 inch in diameter had their ends levelled by means of 

 a fine steel saw, and were placed in the expansion-apparatus and tested as 



