112 Hare's JVew Galvanic jSjjparaius, Theory, ^c. 



sion through the tube, replacing the oxide in its situatiou, 

 should it be dispersed. If the charges are sufficiently pow- 

 erful, a part of the tube will soon be stained with metallic tin 

 which has been revived by the action of transmitted elec- 

 tricity." It cannot be alleged that in such decompositions 

 the divellent polar attractions are exercised like those 

 which characterize the action of wire proceeding from the. 

 poles of a voltaic apparatus. The particles were dispersed 

 from, instead of being attracted to the wires, by which the 

 influence was conveyed among them. This being undenia- 

 ble, it can hardly be advanced that we are to have one mode 

 of explaining the separation of the elements of brass by an 

 electrical discharge, another of explaining the separation of 

 the elements of water by the same agent. One rationale 

 when oxygen is liberated from tin, and another when libe- 

 rated by like means from hydrogen. In the experiment in 

 which copper was precipitated by the same philosopher at 

 the negative pole, we are not informed vi^hether the oxygen 

 and acid in union with it were attracted to the other ; and 

 the changes produced in litmus are mentioned not as simul- 

 taneous, but successive. The violet and red rays of the 

 spectrum have an opposite chemical influence in some de- 

 gree like that of voltaic poles, but this has not led to the 

 conclusion that the cause of galvanism and light is the same. 

 Besides, admitting that the feeble results obtained by Wol- 

 laston and Van Marura are perfectly analogous to those ob- 

 tained by the galvanic fluid, ere it can become an objection 

 to my hypothesis, it ought first to be shown that the union 

 between caloric and electricity, which I suppose productive 

 of galvanic phenomena, cannot be produced by that very 

 process. If they combine to form the galvanic fluid when 

 extricated by ordinary galvanic action, they must have an 

 affinity for each other. As I have suggested in my me- 

 moir, when electricity enters the potes of a metal it may 

 unite with its caloric. In Wollaston's experiments, being 

 constrained to enter the metal, it may combine with enough 

 of its caloric to produce, when emitted, results slightly ap- 

 proaching to those of a fluid in which caloric exists in great- 

 er proportion. 



But once more I demand why, if mechanical electricity 

 be too intense to produce galvanic phenomena, sbould it be 

 rendered more capable of producing them by being still 

 more concentrated. 



