178 Miscellaneous Intelligence. 



in the same direction, and so that the square portion may be 

 entirely immersed in the water of one glass, whilst the tail 

 barely touches that in the next. The circle remaining open, 

 communicate one of its extremities with the earth, and the 

 other with a good condenser ; and it will be found that the ap- 

 paratus has two poles, that corresponding to the squares of 

 metal, being vitreous (positive), and the other resinous (ne- 

 gative). 



An apparatus similar to the preceding, tlie metallic elements 

 of which arc long parallelograms, will not give any electric 

 signs, whilst the pieces of metal are plunged into the water 

 equally at both extremities ; but . as soon as they are unequally 

 immersed, the electricity becomes evident at the two poles, as 

 in the preceding apparatus ; the vitreous pole always corre- 

 sponding to the metallic surface the farthest in the water, so 

 that the same pole may be made either positive or negative, by 

 plunging the metallic extremities, which correspond to it, more 

 or less into the water. 



The same effects are produced by using zinc, and even 

 copper, in place of tin, but oxide of manganese produces no 

 effects. 



The binary pile does not charge the condenser immediately ; 

 the electricity does not become evident in less than half a 

 minute, or even a longer period, and it increases by degrees. 

 It may be supposed that this effect is produced by the oxidation 

 of the tin, as then the pile would have three elements ; but at 

 the end of many days, the electric tension was the same as at 

 its first arrangement, though not the slightest trace of oxida- 

 tion could be perceived. That the developement of electricity 

 by the binary pile is not produced by oxidation is proved also 

 by the circumstance, that in using zinc in place of tin, the 

 electricity diminishes as the oxidation increases, until it dis- 

 appears, after which it again re-appears, but in the contrai7 

 order. 



A pile constructed of ten discs of tinned paper, without the 

 addition of any other substance, gave to Bennet's electrometer, 

 combined with a coHd€nser, a divergence of the third of an 



