in Chemical Combinations. 



497 



Table VIII.— Experiments on the Heat evolved by the Mercury 

 Spiral in the can of water used in the experiments of Table VI. 

 Pile of 4 cells. 2 lbs. 11 oz. of water in the can. 



Besides the correction on account of the difference between 

 the mean temperature of the liquid and that of the room in which 

 the experiments were made, it was necessary to supply the second 

 correction given in the above tables, on account of the capacity 

 for heat of the jars being necessarily somewhat different from 

 what it was in the experiments of Tables V. and VI. In Table VI. 

 the can contained 2 lbs. 12 oz. of water, and the coil of silver 

 wire; whereas it contained 2 lbs. 11 oz. and the coil of mercury 

 in Table VIII. Again, in the experiments of Table V. there 

 were 3 lbs. of solution of copper along with the platinum and 

 copper electrodes ; whereas in those of Table VII. the mercury coil 

 was substituted for the electrodes, whilst the weight of the solu- 

 tion was two grammes less than before. It would be tedious 

 and unnecessary to give in detail the various reductions de- 

 manded by these circumstances ; suffice it to say, that the cal- 

 culations were founded upon the best tables of specific heat, and 

 were made with the most scrupulous care. 



The tin can containing (as in the experiments of Table VI.) 

 the coil of silver wire and 2 lbs. 12 oz. of water, was found by 

 careful calculations to be equivalent in its capacity for heat to 

 1283*7 grms. of water; consequently from Tables VII. and 

 VIII. we obtain for the capacity of the jar of solution used in 

 the experiments of Table V, 



2-6412 36-99 



2-6183 10-622 



x 1283-7 = 11 79-2. 



Referring now to Tables V. and VI., and remembering that 

 'Phil. May. S. 4. No. 21. Suppl. Vol. 3. 2 K 



