HALOID COMPOUNDS OF SILVER, MERCURY, LEAD, AND COPPER. 1157 
Melting point =494° C. 
Specific gravity 5*716. 
The alloy expanded on heating from 0° C. to 194° C., then it simply absorbed heat 
without either expanding or contracting till it attained a temperature of 214° C. 
Rapid contraction now took place, and continued through 66° C., viz.: to 280° C. At 
this temperature the mass began to expand with the same coefficient as that possessed 
by the previous alloy (No. 2) above 298° C. 
The coefficient of cubical expansion for 1° C. from 0° C. to 177° C. was 
*00002307. 
Between 177° C. and 194° C. the coefficient diminished to 
*000012855. 
Then the alloy simply absorbed heat without change of volume. 
At 214° C. it commenced to contract under a negative coefficient of 
*00017424. 
This continued until a temperature of 280° C. had been reached, when expansion 
commenced under the coefficient of 
*00009474 for 1° C. 
This continued to the melting point. 
The following volumes correspond to the temperatures given :— 
Volume at 0° C 
„ 177 
„ 194 
„ 214 
„ 280 
„ 300 
„ 400 
melting point (494° C.) (solid). . . 
„ ,, (494° C.) (liquid) . . 
= 1-000000 
=1-004083 
=1-004301 
= 1-004301 
= -992902 
= -994796 
=1-004270 
=1-013225 
=1-081637 
4. Copper-silver iodide alloy, Cu 2 I 2 .4AgI. 
The percentage of silver iodide was further increased to 71 by the addition of a 
fourth molecule. 
Cu 2 I 2 .4AgI contains: — 
Cu 2 I 3 .= 28-7775 Copper.= 9-5820 
Ag-I.= 71-2225 Silver.= 32'6994 
Iodine. = 57-7186 
100-0000 100-0000 
