298 



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



It will be seen that this alloy has two temperatures of maximum density 

 or minimum volume, the one 133° C, the other about —84° C, if we as- 

 sume that the coefficient of expansion is the same between — 100° C. 

 and 0° C. as it is between 0° C. and 100° C. 



4. ChLORO-BEOM-IODIDE of SILYEE HAVIlfG THE COMPOSITION AG3 I3 Ag 



Ee Ag Cl, oe Ag. I3 Be Cl. 

 The alloy contains : — 



Specific gravity 5*9717. Calculated specific gravity on the assump- 

 tion that no condensation takes place = 5*741, showing a condensation 

 equal to '0385 on the calculated volume. Pusing-point 330° C. Specific 

 gravity of the liquid at the fusing-point = 5*643 ; at 750° C. = 5*333. 

 Fused to a dark bromine-red liquid, and passed through the same 

 changes of colour as alloy No. 3, finally cooled to a dull orange solid. 

 Lustrous. Turned green on exposure to hght. More brittle and less 

 compact than the preceding. Expanded in cooling and broke the glass 

 tube in which it was cast during the cooHng, but not vigorously. A 

 few longitudinal rifts appeared in the rod. At 250° C. sufficiently 

 flexible to be bent through more than a right angle, but was brittle 

 when cold. In the expansion-apparatus the bar expanded up to 124° 

 C. to a less extent than the preceding ; between 124° C. and 133° C. 

 it contracted to a greater extent than the preceding ; at 133° C. it 

 commenced to expand again, and between 130° C. and 330° C. it ex- 

 panded less than the preceding. At the melting-point and at 750° C. 

 the volume was less than that of any of the preceding. 

 The following results were obtained : — 



Agl.... 68*0171 

 AgBr .. 18*1379 

 AgCl .. 13*8450 



Ag . . . . 52*0984 



1 36*7583 



Br .... 7*7183 



Cl .... 3*4250 



100-0000 



100-0000 



Coefficient of cubical expansion for 1° C. 



Between and 124 



„ 124 and 133 (contraction) 

 133 and 330 



° C. ° C. 



Expansion on passing from the solid to the liquid state 



Between 330° C. and 750° C, 



•00006000 



*00259998 



•00011571 



•048033 



•00012359 



If we take the volume at 0° C. as unity we have — 



°0. 



Volume at = 1*000000 

 124 = 1*007440 

 133 = -984041 



