On tivo new Classes of Galvanic Condiiclors. 303 



ivor\' : but other masses of these same substances presenting 

 these phsnnmena in a very equivocal manner only, I abs- 

 tain from deciding i:pon them, and confine myself to 

 pointing out soap and the flame of the phosphorus as com- 

 posing the fifth class of substances, which, when applkd to 

 each individual pole, act as excellent conductors, hut which, 

 u hen interposed between one pole and the other, isolate t/ie 

 positive effect, ivilhout ceasing to conduct in a perfect manner 

 the negative ekctriciiy. 



In order to describe precisely the whole of these phceno- 

 mena by concise expressions which may fix them in the 

 memory, I propose the following nomenclature, for avoid- 

 ing circumlocutions, and to banish equivocal expressions. 



The bodies which we may apply to the poles of a pile are : 

 Isolating (A), 1st class. 

 Conductors perfect (B), 2d class. 



rEipolar (C), 3d class. 



1 TT • 1 fPositive (D), 4lh class. 

 V. unipolar < ,. -, 



' i Negative 



Ditto imperfect < Cv> •.■ ,j\\ 



I'e (E), 5lh class. 



A. Isolating ly their contact. — These do not change any 

 of the two poles separately,' and do not take aw^ay the charge 

 from any of them in the conflict of the two poles ; they 

 consequently isolate every effect at the two poles at once. 

 Such are, glass, roots, water, water in a slate of vapour, 

 sulphur and its flame, amber but not its flame, ^c. 



B. Perfect conductors. — They charge and discharge each 

 individual pole^ but in the conflict of the two poles every 

 vestige of polarity disappears at the positive as at the nega- 

 tive, and the circle is perfectly closed. To this class belong 

 the metals, and all of them in the same degree. 



C. Imperfect conductors. — The characteristic eflects of the 

 two poles may also be discerned during the application of 

 these substances to the two poles simultaneously. They are 

 divided into three classes. 



Bipolar. — They close the Galvanic circle, but they pre- 

 sent in their length two stripes opposed to each other by 

 their electrical eflects. IFater in a fluid state, and such 

 hodies as are impregnated with it, 



D. Puiilive 



