Voltaic Battery of amalgamated Zinc, 339 



dilute sulphuric acid, is active only whilst the electrodes are 

 connected, and ceases to act or be acted upon by the acid the 

 instant the communication is broken. 



JOOl. I have had a small battery often pairs of plates thus, 

 constructed, and am convinced that arrangements of this kind 

 will be very important, especially in the development and il- 

 lustration of the philosophical principles of the instrument. 

 The metals I have used are amalgamated zinc and platina, 

 connected together by being soldered to platina wires, the 

 whole apparatus having the form of the couronne des tasses. 

 The liquid used was dilute sulphuric acid of sp. gr. 1*25. No 

 action took place upon the metals except when the electrodes 

 were in communication, and then the action upon the zinc was 

 only in proportion to the decomposition in the experimental 

 cell ; for when the current was retarded there, it was retarded 

 also in the battery, and no waste of the powers of the metal 

 was incurred. 



1002. In consequence of this circumstance, the acid in the 

 cells remained active for a very much longer time than usual* 

 In fact, time did not tend to lower it in any sensible degree ; 

 for whilst the metal was preserved to be acted upon at the 

 proper moment, the acid also was preserved almost at its first 

 strength. Hence a constancy of action far beyond what can 

 be obtained with the use of common zinc. 



1003. Another excellent consequence was the renewal, du- 

 ring the interval of rest between two experiments, of the first 

 and most efficient state. When an amalgamated zinc and a 

 platina plate, immersed in dilute sulphuric acid, are first con- 

 nected, the current is very powerful, but instantly sinks very 

 much in force, and in some cases actually falls to only an 

 eighth or a tenth of that first produced (1036.). This is due 

 to the acid which is in contact with the zinc becoming neutral- 

 ized by the oxide formed; the continued quick oxidation of 

 the metal being thus prevented. With ordinary zinc, the 

 evolution of gas at its surface tends to mingle all the liquid 

 together, and thus bring fresh acid against the metal, by which 

 the oxide formed there can be removed. With the amalga- 

 mated zinc battery, at every cessation of the current, the sa- 

 line solution against the zinc is gradually diffused amongst 

 the rest of the liquid ; and upon the renewal of the contact, 

 with the electrodes, the zinc plates are found most favourably 

 circumstanced for the production of a ready and powerful 

 current. 



1004. It might at first be imagined that amalgamated zinc 

 would be much inferior in force to common zinc, because of 

 the lowering of its energy, which the mercury might be sup- 



2X2 



