Electrodes in the Galvanic Arc of Light. 9 



On this account I confined myself at first to the investigation of 

 iron, nickel, and copper. 



In the experiments with these metals the results showed not 

 the remotest approach to regularity in respect of the quantities 

 disintegrated. I content myself with bringing forward a few 

 experiments and remarking only that the electrodes formed cylin- 

 ders rounded at the fore end, of at most 4 or 5 grammes weight. 



Experiment 1. 



Hydrogen developed in the voltameter, 31 cub. centims. or 

 2-78 milligr. 



The positive electrode of iron, lost 7 milligr. iron, and took 

 up 3 milligr. copper. 



The negative electrode of copper, lost 4 milligr. copper, took 

 up 1 milligr. iron. 



Experiment 2. 



Hydrogen developed in the voltameter, 20 cub. centims. = 

 1*78 milligr. 



Positive electrode iron, lost 5 milligr. iron, took up 4 milligr. 

 copper. 



Negative electrode copper, lost 5 milligr. copper, took up 0*5 

 milligr. iron. 



Experiment 3. 



Hydrogen developed in the voltameter, 65 cub. centims. = 

 5-82 milligr. 



Positive electrode iron, lost 36 milligr. iron, took up no copper. 



Negative electrode copper, lost 10 milligr. copper, took up 3 

 milligr. iron. 



Experiment 4. 



Hydrogen developed in the voltameter, 48 cub. centims. = 

 4*3 milligr. 



Positive electrode iron, lost 6 milligr. iron, took up no copper. 



Negative electrode copper, lost 9 milligr. copper, took up 1 

 milligr. iron. 



Experiment 5. 



Hydrogen developed in the voltameter, 89 cub. centims. = 

 7*97 milligr. 



Positive electrode iron, lost 9 milligr. iron, took up a trace of 

 copper. 



Negative electrode copper, lost 18 milligr. copper, took up 7 



5 ' ' Experiment 6. 



Hydrogen developed in the voltameter, 60 cub. centims. = 

 5*38 milligr. 



Positive electrode copper, lost 8 milligr. copper, took up 4*5 

 milligr. iron. 



