1138 
MR. G. F. RODWELL ON THE EFFECTS OF HEAT ON CERTAIN 
of cooling lond 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. 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. Rods of 6 inches 
long by ‘3 inch in diameter had their ends levelled by means of a fine steel saw, and 
were placed in the expansion-apparatus, and tested as described in the case of the 
iodide of silver bars. The coefficient of cubical expansion for 1° C. was found to be 
*000095454. 
Fizeatj by his optical method found the coefficient to be *000098814. The co¬ 
efficient increases with the temperature, at least to the extent of *000003 for each 
100° C. increase of range. The expansion is considerable in passing from the solid to 
the liquid condition. 
The volumes corresponding to the different temperatures and certain physical pro¬ 
perties are tabulated below with those of the bromide of silver. 
The chloride fuses to a dull light-red liquid, and becomes faintly yellow when 
solidified; in thin layers, colourless and quite transparent. When cold, it forms a pale 
greenish-yellow solid, also transparent in thin layers. No sounds were emitted during 
cooling. In thin layers the chloride is very flexible when cold; and thick rods of it 
are flexible while hot. It has a decided metallic ring if struck when cold. 
Chloride of silver. 
Bromide of silver. 
Fusing point. 
451° 0. 
427° C. 
Specific gravity at 0° 0. 
5-505 
6-245 
„ „ fusing point. . . . 
4-919 
5-595 
Volume at —60° C. 
1-000000 
1-000000 
„ -io° C. 
„ 0° 0. 
1-005547 
1-006060 
„ 70° 0. 
„ 100 ° c. 
1-015092 
1-016560 
„ 142° 0. 
„ 200° 0. 
1-024937 
1-027460 
„ 300° 0. 
1-035082 
1-038760 
„ 400° C. 
1-045227 
1*050460 
,, fusing point (solid) . . . 
1-050319 
1-053470 
„ „ „ (liquid) . . . 
1-116427 
1-122840 
Physical structure, &c., of fused mass . 
Crystalline fracture; thin layers 
transparent and flexible; thick 
rods very flexible when hot. 
Crystalline and brittle. 
