ELECTRO-CHEMICAL POLARITY OF GASES. 357 



hydrogen or atmospheric air intensely heated showed no sign 

 of conduction for voltaic electricity, even when a battery of 

 very high intensity was employed. 



In the Eleventh, Twelfth, and Thirteenth Series of Fara- 

 day's Experimental Researches the line of demarcation be- 

 tween induction across a dielectric and electrolytic discharge 

 is repeatedly adverted to ; induction is regarded as an action 

 of contiguous particles, and as a state of polarisation anterior 

 to discharge, whether disruptive, as in the case of dielectrics, 

 or electrolytic, as in electrolytes. See 1164, 1298, 1345? 

 1368, &c. 



Mr. Gassiot, in a paper published in the year 1844,* has 

 shown that the static effects, or effects of tension, produced by 

 a voltaic battery, are in some direct ratio with the chemical 

 energies of the substances of which the battery is composed ; 

 in other words, that in a voltaic series, whatever increases the 

 decomposing power of the battery when the terminals are 

 united by an electrolyte, also increases the effects of tension 

 produced by it, when its terminals are separated by a di- 

 electric. 



In none of the above papers, and in no researches on elec- 

 tricity of which I am aware, is there any experimental evidence 

 that the polarisation of the dielectric is or may be chemical 

 in its nature ; that, assuming a dielectric to consist of two sub- 

 stances having antagonistic chemical relations, as for instance 

 oxygen and hydrogen, the particles of the oxygen would be 

 determined in one direction, and those of the hydrogen in the 

 other ; the only experimental result bearing on this point 

 with which I am acquainted is the curious fact which was 

 observed by Mr. Gassiot and some other electricians who ex- 

 perimented with him in the year 1838, viz. that when two 

 wires forming the terminals of a powerful battery were placed 

 across each other, and the voltaic arc taken between them, the 

 extremity of the wire proceeding from the positive end of the 

 battery was rendered incandescent, while the negative wire 

 remained comparatively cool ; it was at that time believed 

 that there was some effect exhibited here extra the voltaic 



* Phil. Trans., 1844, p. 39, 



