GALVANIC INSTRUMENTS. 



337 



about the zinc pole, or articles attached to it, less of the 

 surface of the silver plate is to be immersed in the solution, 

 or the article to be plated will be discolored. A solution 

 of gold may be made in the same manner by using a plate 

 of gold, etc. 



Smee's Battery. (Fig. 399.) A piece Fig. 399. 

 of platinized silver has a bar of wood fixed 

 on the top to prevent contact with the 

 zinc, and is furnished with a binding 

 screw. A stout plate of well amalga- 

 mated zinc, of the width of the silver, is 

 placed on each side of the wood, and both 

 are held in their place by a binding screw 

 sufficiently wide to embrace the zincs and 

 the wood. This arrangement is immersed 

 in a jar or glass, containing dilute sul- 

 phuric acid, in the proportion of one of 

 acid to seven of water, and not the slight- 

 est effect is produced till a communication 

 is made between the metals, when it in- 

 stantly hisses and bubbles, and an active galvanic battery is 

 obtained. This battery is simple in its construction, ma- 

 nageable in its application, and neat in its appearance ; and 

 although it has not the constancy of Daniell, or the wonder- 

 ful activity of Grove, it may be kept in active operation for 

 several days. Price, small size, 82.25. 



" larger " $5.00. 



Grove's Battery, as arranged ly Benj. Pike, Jr. The most 

 powerful galvanic battery that has yet been brought before 

 the public, is that of Professor Grove, who was led to the 

 discovery of a galvanic combination much more powerful 

 than any previously known.* The elements used, are a 



* The manufacturer had occasion to use one of these batteries at a 

 public lecture, by Dr. Lardner, at the Tabernacle in New York, 

 before a large audience, The battery consisted of eighteen series, 

 contained in a small case that could be conveniently lifted about by 

 one person. The effect of the battery when the charcoal points 

 were used was most brilliant, illuminating the whole building ; and 

 when steel watch springs and iron turnings were burned, the most 

 brilliant scintillations were produced. Also exhibited one in Niblo's 

 Garden, at the Fair of the American Institute, in Oct., 1845, before 

 a number of distinguished scientific gentlemen; the battery pro- 

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