4,32 Dr. Wollaston’s Experiments on 
placed in absolute contact with them. Hence it appears, that 
decomposition of water may take place by common electricity, 
as well as by the electric pile, although no discernible sparks are 
produced. 
The appearance of two currents of air may also be imitated, 
by occasioning the electricity to pass by fine points of com- 
munication on both sides of the water ; but, in fact, the resem- 
blance is not complete ; for, in every way in which I have tried 
it, I observed that each wire gave both oxygen and hydrogen 
gas, instead of their being formed separately, as by the electric 
pile. 
I am inclined to attribute the difference in this respect, to the 
greater intensity with which it is necessary to employ common 
electricity ; for, that positive and negative electricity, so excited, 
have each the same chemical power as they are observed to have 
in the electric pile, may be ascertained by other means. 
In the precipitation of copper by silver, an instance of de- 
oxidation (or phlogistication) by negative electricity has been 
mentioned : the oxidating power of positive electricity may be 
also proved, by its effect on vegetable blue colours. 
Exper. 8. Having coloured a card with a strong infusion of 
litmus, I passed a current of electric sparks along it, by means 
of two fine gold points, touching it at the distance of an inch from 
each other. The effect, as in other cases, depending on the small- 
ness of the quantity of water, was most discernible when the card 
was nearly dry. In this state, a very few turns of the machine 
were sufficient to occasion a redness at the positive wire, very 
manifest to the naked eye. The negative wire, being afterwards 
placed on the same spot, soon restored it to its original blue 
colour. 
