DURING METALLIC SUBSTITUTIONS. 
97 
First Series. — Sulphate of Copper and Iron. 
I. Air 14°’7. Increment found 1°'68, corrected 1°’68. 
Water 246*4 grms. Solution and vessels (equivalent to) 59* 1 grms. 
II. Air 14°*9. Increment found 1°*68, corrected 1°*68. 
Water 244*3 grms. Solution and vessels 59*1 grms. 
III. Air 14°*4. Increment found 1°*65, corrected 1°*68. 
Water 243*5 grms. Solution and vessels 59*1 grms. 
Hence we have for the heat of combination referred to 1 grm. copper as unit, 
I. II. III. Mean. 
584° 580° 579° 581°. 
Chloride of Copper and Iron. 
I. Air 15°*5. Increment found 1°*775 corrected 1°*77- 
Water 243*1 grms. Solution and vessels 59*5 grms. 
II. Air 14°*2. Increment found l°’77j corrected 1°*77- 
Water 242*5 grms. Solution and vessels 59*5 grms. 
I. II. Mean. 
609° 610° 609°*5. 
The greater amount of heat in the latter experiments arose from the protochloride 
of iron absorbing oxygen more rapidly than the protosulphate. In the next series 
this source of error was avoided, and the results agree better with each other. 
Second Series.— \n these experiments the salts were dissolved in recently boiled 
water, and a small bubble of air only was left in the containing vessel. Each solu- 
tion weighed 126*7 grms. and contained 0*456 grm. oxide of copper. 
Sulphate of Copper and Iron. 
I. Air 15°*5. Increment found 1°*64, corrected 1°*62. 
Heat of combination 593°. 
Chloride of Copper and Iron. 
I. Air 15°*5. Increment found 1°*64, corrected 1°*61. 
Heat of combination 590°. 
Taking the mean of the last experiments, we obtain for the heat extricated during 
the precipitation of 
C. F. 
1 grm. copper by iron .... 592° or 1066° 
1 equiv. copper by iron .... 2342° or 4216°. 
Salts of Copper with Lead. 
Acetate of Copper and Lead. — As before, 100 grms. of a solution of aeetate of copper 
MDCCCXLVIII. 
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