1156 
MR. G. F. RODWELL OH THE EFFECTS OF HEAT OH CERTAIH 
The alloy fused at 496° C. 
Specific gravity =5*7225 to 5*7377. 
It did not expand on solidifying. The fracture was resinous, and it was more 
brittle than the preceding. Annealing in paraffine did not diminish the brittleness. 
In the mass it was brown; in thin layers yellow and transparent; in powder a 
brilliant yellow. Unaffected by light. 
The alloy expanded on heating from 0° C. to 221° C. with a cubical coefficient for 
1° C. of 
*00003750. 
Between 221° C. and 233° C. it simply absorbed heat without either expanding or 
contracting. 
At 233° C. it commenced to contract, with a negative coefficient of 
*00010587. 
This continued until a temperature of 298° C. had been attained, viz.: through 
65° C., when expansion commenced with a coefficient of 
*00009474 for 1° C. 
and continued until the melting point had been attained. 
The following volumes correspond to the temperatures given :—- 
Volume at 0° C.=1-000000 
„ 221 .=1-008287 
„ 233 =1-008287 
„ 298 =1-001406 
„ 300 =1-001595 
„ 400 =1-011069 
,, melting point (496° C.) (solid).=1-020164 
„ „ „ (496° C.) (liquid) .... =1-062958 
3. Copper-silver iodide alloy , Cu 2 I 2 .3AgI. 
The percentage of iodide of silver was further increased to 65 by the addition of 
another molecule. 
Cu 2 I 2 .3AgI contains :— 
Iodide of copper ... = 35*0116 Copper. = 11-6558 
Iodide of silver ... = 64-9884 Silver.= 29-8335 
Iodine. = 58-5107 
100-0000 100-0000 
The alloy was more brittle than the preceding. Fracture, as before, resinous. 
Colour: in the mass, brown; in thin laminae, yellow and transparent; in powder, a 
brilliant yellow. Unaffected by light. 
