56 MANAGEMENT OF BATTERIES, 



metallic contact being insured by the cleanliness of those portions* 

 of the apparatus which require to be in direct connection with 

 each other cannot be too strictly enforced. 



Amalgamation of the Zincs. In the course of this chapter we 

 have had frequent occasion to speak of the amalgamation of zinc, 

 that is to say, the covering zinc with a coating of mercury, to 

 prevent the rapid action which would otherwise take place be- 

 tween the liquid and the metal. For the proper and profitable 

 use of these batteries, it is necessary that this amalgamation 

 should be so perfect, that no action should be apparent until the 

 circuit is completed. The zincs sold at the philosophical instru- 

 ment makers are generally properly amalgamated ; but after some 

 little use, it will be found that the metal requires a fresh amal- 

 gamation, otherwise, by the local action, as it is usually termed 

 by electricians, taking place betwen the acid and the metal, the 

 zinc will be rapidly consumed. In an economical point of view, 

 therefore, as well as for obtaining the full power of the battery 

 (for, however energetic this local action may be, it does not 

 increase in any way the power of the battery, but has a directly 

 contrary effect) it is advisable invariably to re-amalgamate the 

 zinc the moment any action of this kind is apparent. This is 

 easily effected ; it is only necessary to remove the zinc from the 

 battery, rinse it in a little cold water, and to pour on it a few 

 drops of mercury, which will immediately attach themselves to 

 the zinc, and may be rubbed uniformly over its surface by means 

 of a little pad of tow. It requires but little trouble to do this, 

 and the result will in all cases be found amply to repay it. 



While on this matter, it may be well to press upon the reader 

 the necessity of invariably cleansing the battery before it is 

 finally set aside. The acid solution shoul.d not be thrown away, 

 as it will serve for many operations. It is not until any consi- 

 derable quantity of sulphate of zinc is formed that the voltaic 

 action is rendered less energetic. The plates should always be 

 thoroughly rinsed in cold water, and set aside to drain. The 

 platinas of Grove's battery should be thoroughly well washed, 

 dried with blotting paper, and kept perfectly smooth until again 



