498 



Messrs. Gladstone and Tribe on a 



[June 15, 



III. " On a Law in Chemical Dynamics." By John Hall Glad- 

 stone, Ph.D., E.R.S., and Alfred Tribe, F.C.S. Received 

 May 25, 1871. 



(Abstract.) 



It is well known that one metal has the power of decomposing the salts 

 of certain other metals, and that the chemical change will proceed until 

 the more powerful metal has entirely taken the place of the other. The 

 authors have investigated what takes place during the process. 



The experiments were generally performed as follows : — 72 cubic centi- 

 metres of an aqueous solution of the salt of known strength, and at 12° 

 Centigrade, were placed in a tall glass ; a perfectly clean plate of metal of 

 3230 square millimetres was weighed and placed vertically in this solution 

 without reaching either to the top or bottom ; the action was allowed to 

 proceed quietly for ten minutes, when the plate was removed, and the de- 

 posited metal was washed off. The loss of weight gave the amount of 

 metal dissolved, and represented the chemical action. 



The most complete series of results was with copper and nitrate of* 

 silver. 



Mtrate-of-silver 

 solution. 



Copper dissolved. 

















Theo- 

 retical. 



Differ- 

 ence. 



•Propor- 

 tional 

 number. 



Percentage 

 of salt. 



Actual weights. 



Average. 



1. 



2. 

 3. 

 4. 

 5. 

 6. 



7. ' 



8. 



9. 

 10. 

 11. 

 12. 

 14. 

 16. 

 20. 

 24. 

 30. 

 32. 

 40. 

 48. 

 60. 

 70. 



03541 



0- 7083 



1- 0623 

 1-4166 



1- 7705 



2- 1246 

 2-4788 



2- 8332 



3- 1873 

 3-5415 



3- 8956 



4- 2497 



4- 9580 



5- 6664 



7- 0830 



8- 4994 



10- 624 



11- 333 

 14-166 

 16-999 

 21-246 

 24-788 



0-0045, 0-0050 



0135, 0-0140 



0-0240, 0250 



0-0420 



0-0600 



00785 



0-0975 



01230, 0-1230 

 0-1510, 0-1480 

 0-1680, 0-1670 

 01955 



0-2170, 0-2285, 0-2310, 0-2200 



0-2740 



0-3270 



0-4540, 0-4100 

 0-5400 

 0-6850 

 0-7100 



0- 8440, 0-9090 



1- 0690 

 1-359 

 1-580 



00475 



0-01375 



0-0245 



0420 



0-0600 



0-0785 



0-0975 



0-1230 



04495 



0-1675 



0-1955 



0-2241 



2740 



0-3270 



0-4320 



0-5400 



0-6850 



0-7100 



0- 8765 



1- 0690 

 1-359 

 1-580 



0-00455 



001365 



0-0259 



0-0409 



0-0583 



0790 



0-0994 



0-1228 



0-1481 



0-1749 



0-2035 



0-2336 



0-2982 



+0-0002 

 +00001 

 -0-0014 

 +0-0011 

 +0-0017 

 -0 0005 

 -00019 

 +0-0002 

 +0-0014, 

 -0-0074 

 -0-0080 

 -00095 

 -00242 



In the earlier terms of this series, twice the percentage of silver-salt gives 

 three times the chemical action. The close agreement of the observed 

 numbers with those calculated on this supposition as far as the 9th term 



