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400 pairs each of 42 inches of zinc surface; as a series of 200 pairs 

 each of 84 inches of zinc surface; or as a series of 100 pairs each of 

 168 inches of zinc surface. In the usual mode of constructing the 

 voltaic apparatus, the diversities of power that appertain to an appa- 

 ratus in which the ratio of the size of the pairs to their number va- 

 ries, as above described, can only be produced by changes in the ar- 

 rangement, which are too inconvenient to be employed; but, accord- 

 ing to the contrivance described, are attainable simply by shifting the 

 connecting arches, so as to alter duly the mode in which the recepta- 

 cles are connected with each other. 



By means of this apparatus, the deflagration of metals, the arched 

 flame between charcoal points, the fusion of platina by contact with 

 the aqueous solution of chloride of calcium, the welding of iron wire 

 to a rod of the same metal under water, were all accomplished with 

 the most striking success. 



In repeating Davy's experiment, in which the arched flame between 

 charcoal points was subjected to the influence of a permanent mag- 

 net, the reaction between the voltaic and magnetic fluids was so vio- 

 lent, as to be productive of a noise like that of small bubbles of hy- 

 drogen inflamed in escaping from the generating liquid. This last 

 mentioned experiment was performed by request of Prof. Henry, who 

 manipulated in the performance of it. 



Dr. Hare stated, that he had for many years endeavoured to draw 

 the attention of men of science to the fact, that if, when a fine and a 

 coarse wire of platina are made to form the electrodes or poles of a 

 powerful voltaic series of not less than 300 pairs, the coarse wire, 

 while forming the positive end or anode, be introduced into a concen- 

 trated solution of chloride of calcium, and the fine wire be made to 

 touch the surface of the solution, fusion of the extremity into a glo- 

 bule will follow every contact. But when the polarity of the wires is 

 reversed, the resulting ignition is comparatively feeble. 



This experiment, Dr. Hare stated, was repeated to the satisfaction 

 of Professors Silliman, Henry, and James Rogers, all of whom were 

 present at the trial of the apparatus. 



When the finer wire was plunged about an inch below the surface 

 of the solution, it became luminous throughout, emitting rays of a 

 brilliant purple hue. 



For the fusion of the platina wire, in the experiment above de- 

 scribed, it was found necessary to use the whole series consecutively 

 as 400 pairs; showing, Dr. Hare remarked, that there are effects 



