new Mode of producing Fire. 7 



The phenomena of light, which appear by a sudden com- 

 pression of the air, but never on a slow compression of it, 

 however powerful, will be deducible from an electric rever- 

 sion, when considered under the same point of view, which is 

 often indicated when bodies in the same electrical state are 

 quickly moved towards each other, that the weaker electricity 

 is opposed by the stronger, as is the case with magnets. It 

 is an opinion which contradicts itself, to suppose that those 

 appearances of light are owing to a mechanical expulsion of 

 caloric which has been chemically fixed in the air. In order 

 to cover a little this contradiction, it is said that the capacity 

 of the air for caloric is diminished by compression : but this 

 means nothing else, we would say, but that light and caloric 

 become free, because they become free. Besides this, such a 

 peculiar explanation cannot assign any reason why those ap- 

 pearances of light are never elicited by a rapid compression of 

 hydrogen or azote, but always in a high degree in that of oxygen 

 or halogen [chlorine]. Neither can the favourite theory of fixed 

 caloric assign any ground of distinction in this respect with 

 regard to the last-mentioned gases, since they, like the former, 

 consist of a ponderable base and of fixed caloric. Why, 

 therefore, does this fixed caloric appear with such strong light 

 only in those gases which are attracted to the positive pole of 

 the Voltaic battery, viz. in oxygen and in chlorine ? Accord- 

 ing to my crystallo-electrical theory, I can with good reason 

 assume, that the crystalline differentials of the last-mentioned 

 gases repel each other with a predominant negative electricity, 

 on account of their being attracted by the positive pole of the 

 Voltaic battery at the moment of their becoming free. If 

 therefore such gases are forcibly compressed, it is the positive 

 electricity which is excited by the electric reversion of the poles 

 of many rapidly approaching crystals. But it is known, that 

 positive electricity possesses a strong radiating power, which 

 negative electricity, constantly appearing in a faint light, is de- 

 ficient in. It is therefore the latter, which according to our 

 crystallo-electrical theory will appear in a strong compres- 

 sion of hydrogen, and generally of all those gases which are 

 attracted to the negative pole. For this reason will the com- 

 pression of such gases elicit caloric only, and not light. It 

 should not be objected that a decided manifestation ot electri- 

 city has never been perceived in these appearances of light ; 

 for as the products of both electricities, viz. light and heat, 

 are present, the appearance of the electricities separately can- 

 not be expected. Moreover, the crystallo-electricity is here 

 meant, which, as is well known, imparts itself but with diffi- 

 culty, Where il appears tin: more powerful, as is the case in 



the 



