170 



APPENDIX. 



[No. V. 



to use a vessel of a sixe sufficient to hold liquid to last for seven or ten days. 

 The form of battery now most universally employed 

 for these purposes consists of a piece of silver (s), 

 on the top of which is fixed a beam of wood (w), to 

 prevent contact with the silver. A binding screw 

 is soldered on to the silver to connect it to any re- 

 quired object. A strip of zinc (z), varying at the fancy 

 of the operator from one-half to the entire width 

 of the silver, is placed on each side of the wood, and 

 both are held in their place by a binding screw (b\ 

 sufficiently wide to embrace the zincs and wood. 

 These batteries vary from the size of a tumbler to 

 a 10- or 12 -gallon vessel. In the very extensive 

 application of this battery to the arts, the little 

 pieces of zinc which remain undissolved in the 



riG. y. smee s rsaiiery, - . .... , 



lor Electrotype. battery iorm an important consideration to the 



manufacturer. Some distil the mercury from them, others sell them 

 to the zinc works, whilst others have never turned them to any account 

 at all, waiting patiently in the hope that some more beneficial applica- 

 tion of them might be discovered. These latter have hundredweights 

 of odds and ends in hand which they are desirous to employ. After 

 considering the matter carefully, I have to propose the following use 

 for them ; in fact, I make them the positive pole of a battery, by placing 

 them at the bottom of a vessel and covering them with mercury. A 

 silver wire is then placed down a glass tube into the quicksilver, so 

 that the wire may nowhere touch the dilute sulphuric acid with which 

 the vessel is filled, but simply make a good metallic communication 

 with the mercury. At the other end of the wire a binding screw may 

 be attached, for the convenience of the operator. The platinized silver 

 plate (s) is then to be immersed in the fluid, and placed as near to the 

 mercury as possible, without actually being in contact, whilst no part 

 of it should be more than three inches from it, as a considerable reduction 

 of power would then ensue. This form of battery may be fairly called the 

 Odds-and-Ends Battery ; and though not so philosophical an instrument 

 in its construction as the form last described, yet no manufacturer should 

 be without one to use up the scraps from his other 

 batteries ; and I must say this instrument requires 

 less trouble in its manipulation than any other 

 form I have ever seen. An odds-and-ends com- 

 pound battery, which will only require a binding 

 screw at each end, may be made by placing the 

 mercury and zinc at the bottom of a many-celled 

 porcelain trough ; the platinized silver should be 

 cut into suitable squares, leaving a narrow slip to 

 connect it with the next cell. The strip must be 

 placed in a glass tube, or covered with any non- 

 conducting substance, leaving the end only to dip 

 in the mercury of the next cell. A series of little 

 glasses may be used instead of the many-celled trough for some purposes. 

 The only objection which I have found in this form of compound battery is 

 the possibility of the zinc in one cell being completely exhausted, when the 



FIG. 10. Smee's Odds-and- 

 Ends Battery. 



