334 



BENJ. PIKK S, JR., DESCRIPTIVE CATALOGUE. 



arrangement by wires with the zinc cylinder of the next 

 series, and so in succession, through the arrangement, the 

 unconnected zinc forming the negative pole, and the uncon- 

 nected copper the positive pole. Price, $12.00. 



Fig. 397 



DanielVs Ten-celled Sustaining Battery. (Fig. 397.) 

 The above cut represents a set of ten large batteries united ; 

 the construction the same as the preceding. The cells of 

 this sustaining battery must be plentifully supplied with 

 sulphuric acid, without which the power is but feeble. 

 Mr. Daniell recommends a mixture of eight parts of water 

 and one of sulphuric acid which has been saturated with 

 sulphate of copper for the copper cell, the internal tube 

 being filled with the same acid solution without the copper. 

 The porous cells should be well soaked in dilute sulphuric 

 acid for an hour or two before being used ; and after being 

 removed from the battery, they should be repeatedly rinsed, 

 or allowed to soak for some time in warm water, to dissolve 

 out all the metallic salt from their pores. If this be not at- 

 tended to, they will be soon destroyed. Price, $25. 



Sustaining Battery for Plating, &c. (Fig. 398, next 

 page.) This represents a convenient battery for sustaining 

 magnetic instruments in action for a long time ; also for 

 plating with gold, silver, &c. Any number may be used 



