56 Self-sustaining Voliaic Battery. 
are Le aati se therefore that they cannot entirely prevent 
contact of the plate and liquid. 
That ites seneaieees of the zinc, also, should be referred to 
the attraction of the plate, is that which the universal principle 
of attraction demands. Why not admit that that attractive force 
which we know exists in all things, concurs with the electrical 
tension to produce this, when we are constantly seeing the great- 
~ anomalies produced by concurring forces? Thus we know 
at the affinity of copper for oxygen, at low temperatures, is 
aoa to that of hydrogen; yet, when a piece of coal is satu- 
rated with hydrogen and immersed in a solution of sulphate of 
copper, the hydrogen is oxydized and copper reduced, simply be- 
cause the attraction of the coal for the copper, added to the affin- 
ity of the hydrogen for oxygen, make a united force superior to 
the affinity of copper for oxygen. st _ have a voltaic circle 
composed of coal, sulphate of copper and hydrogen, which 
comes active by the help of attraction, ee is enabled to decom- 
pose an electrolyte whose affinities are even stronger than those 
of the produced electrolyte. 
It has been considered as the standing miracle of electricity, 
and the unanswerable argument against the chemical theory of 
electrical excitation, that a battery will work in a neutral solu- 
plate; for, say the advocates of the electro-motive force, the 
force is greater than the affinity of, zinc for the negative element, 
for after overcoming the conduction resistance, it is still enabled 
to separate zinc from the negative element. But there is a little 
experiment which shows conclusively that it is the state of the 
surface of the conducting plate which determines the electroly- 
sis, and not a supposed electrical condition involved in the nature 
of the substance of the plate. Let a battery of several pairs be 
connected with a pair of large platinum electrodes, in a solution 
of sulphate of zinc, containing a little free acid—or a single bat- 
tery may be used if an electrode of zinc is used to receive the 
oxygen,—then, if the platinum electrode be well polished, zine 
will be rapidly deposited on it, and there will be no hydrogen 
given off; then let the deposited zine be dissolved off, and the 
platinum ‘electrode roughened with emery and well platinized, 
and then restored to its former connection with the battery ; now, 
the same battery, with the same solutions and electrodes, will 
chiefly electrolyze the sulphate of oma ty ; there will be very 
little zine deposited, but the hydrogen will fly off in copious 
streams. 
As the reservoir battery is designed chiefly for telegraphs, I 
with propriety, before closing, say a few words relative to 
the quantity of electricity required to work a telegraph. I have 
measured the quantity of the current on some lines by interpos- 
ing voltametres in the circuit. 
ee | 
. 
