286 
DR. RITCHIE’S EXPERIMENTAL RESEARCHES 
atoms of the vitreous and resinous elements possess polarity, or have the 
strongest tendency to unite at opposite points. These poles will obviously be 
arranged facing each other in a copper and zinc plate, forming an elementary 
battery. This arrangement will re-act on the chain of aqueous molecules, till 
the maximum of effect take place. The electric fluid thus arranged in the 
zinc and copper plates will be partially retained by the coercitive force of the 
metal. Hence it follows that the electric molecules might be so arranged as 
to have opposite poles turned to opposite sides of a thin plate of metal; or, to 
use the usual mode of expression, a thin plate of metal might have one side 
rendered positive and the other negative. The best mode of exhibiting this 
property, which seems first to have been observed by Ritter, is the following. 
Exp. IV. Cement three very thin copper plates, about two inches square, in a 
wooden trough, at the distance of half an inch from each other, having copper 
wires soldered to each. Connect the extreme plates with the ends of a power¬ 
ful battery, the spaces between them being previously filled with diluted acid, 
and allow decomposition to go on for a few minutes. Remove the battery, and 
connect one of the extreme plates and the middle one with a galvanometer, 
and very decided electro-magnetic effects will be observed. Connect the other 
extreme plate and the middle one with the galvanometer, and the needle will 
be powerfully deflected in the opposite direction. 
This appears to offer the true explanation of the secondary piles of Ritter, 
and the more recent experiments of M. De la Rive. 
10. When diluted sulphuric acid is employed in an elementary battery, the 
water is rapidly decomposed, and hydrogen is copiously evolved at the sur¬ 
face of the copper plate, even when a diaphragm of moistened bladder is inter¬ 
posed between the plates. With this acid the electro-magnetic effects are pro¬ 
portioned to the quantity of hydrogen liberated at the copper plate, without 
any regard to the immense quantities which may be liberated at the surface of 
the zinc plate. When nitric acid is employed, a much greater electro-mag¬ 
netic effect is produced, though a much less quantity of hydrogen be now 
liberated at the surface of the copper plate. This acid seems to favour the 
facility of the definite arrangement of the molecules of water, without render¬ 
ing it so easily decomposed. When the surfaces of the zinc and copper plates 
are covered with bubbles of hydrogen, the effect must be much diminished, as 
