Injurious Arrangements of the Voltaic Battery. 4<13 



in which the interposed plates are immersed, with the inten- 

 sity of the current, the strength of the pile, the time of action, 

 and especially with accidental discharges of the plates by in- 

 advertent contacts or reversions of the plates during experi- 

 ments, and must be carefully watched in every endeavour to 

 trace the source, strength and variations of the voltaic current. 

 Its effect was avoided in the experiments already described 

 (1036. &c.), by making contact between the plates P' and P^ 

 before the effect dependent upon the state of the solution in 

 contact with the zinc plate was observed, and by other pre- 

 cautions. 



1041. When an apparatus like fig. 26. (1017.) with several 

 platina plates was used, being connected with a battery able 

 to force a current through them, the power which they ac- 

 quired, of producing a reverse current, was very considerable. 



1042. Weak and exhausted charges should never be used at 

 the same time with strong and fresh ones in the different cells of 

 a trough, or the different troughs of a battery: the fluid in all 

 the cells should be alike, else the plates in the weaker cells, 

 in place of assisting, retard the passage of the electricity gene- 

 rated in, and transmitted across, the stronger cells. Each 

 zinc plate so circumstanced has to be assisted in decomposing 

 power before the whole current can pass between it and the 

 liquid. So that, if in a battery of fifty pairs of plates, ten of 

 the cells contain a weaker charge than the others, it is as if 

 ten decomposing plates were opposed to the transit of the 

 current of forty pairs of generating plates (1031.)' Hence a 

 serious loss of force, and hence the reason why, if the ten 

 pairs of plates were removed, the remaining forty pairs would 

 be much more powerful than the whole fifty. 



1043. Five similar troughs, of ten pairs of plates each, w^ere 

 prepared, four of them with a good uniform charge of acid, 

 and the fifth with the partially neutralized acid of a used bat- 

 tery. Being arranged in right order, and connected with a 

 volta-electrometer (Til.)? the whole fifty pairs of plates yield- 

 ed 1-1 cubic inch of oxygen and hydrogen in one minute; but 

 on moving one of the connecting wires so that only the four 

 well-charged troughs should be included in the circuit, they 

 produced with the same volta-electrometer 8*4 cubical inches 

 of gas in the same time. Nearly seven eighths of the power 

 of the four troughs had been lost, therefore, by their associa- 

 tion with the fifth trough. 



1044. The same battery of fifty pairs of plates, after being 

 thus used, was connected with a volta-electrometer (711.), so 

 that by quickly shifting the wires of communication, the cur- 

 rent of the whole of the battery, or of any portion of it, could 



