and Electrolysis of Chemical Compounds. 44 1 



but glide along the inner surface of the tube. But these 

 bodies are decomposed through elective affinity (by caustic 

 potash for instance) only after a long time and with the aid 

 of heat ; and acids act on them only when a metal is present. 

 This behaviour is in accordance with Hittorf 's theory ; and 

 with respect to the part which hydrogen might play in elec- 

 trolysis, it is to be remarked that these nearly insulating 

 compounds are precisely those which contain no hydrogen*. 



8. Electrolysis of some Hydrocarbons and Haloid Compounds 

 of the Alcohol-Radicals. 



Only two of these compounds which I have investigated 

 (diethyl and dimethyl) required to be condensed. This was 

 easily effected, as they were prepared by Frankland's method 

 from iodide of ethyl and iodide of methyl by decomposition 

 with zinc, heating them in closed tubes. The results are 

 collected in Table VII. (pp. 442, 443). As some of these 

 bodies are indifferent to acids and do not exchange their 

 hydrogen for metals, while others exhibit reciprocal decom- 

 position, they afford an opportunity for again testing the 

 before-mentioned hypotheses. The hydrocarbons examined 

 behave to the galvanic current as very bad conductors. Their 

 chemical behaviour to the strongest acids, such as nitric and 

 sulphuric, varies. Diethyl is quite indifferent, and undergoes 

 no decomposition ; and so is dimethyl to sulphuric acid ; 

 amylene is split up by sulphuric acid ; and these substances 

 form derivatives only by combining directly with the halogens. 

 Benzol, toluol, and naphthaline are extremely bad conductors, 

 and therefore would probably be also chemically neutral. 

 But in these the hydrogen is readily replaced by the halogensf : 

 they are directly decomposed by sulphuric or by nitric acid, 

 water being separated and sulphacids or nitro-compounds 

 produced ; otherwise the alkalies do not attack them, or only 

 at high temperatures. As, then, here neither is hydrogen 

 exchanged for metals, nor does decomposition by proper 

 elective affinity take place, these compounds support my hy- 

 pothesis, as well as that of Hittorf; and this holds good for 

 their substitutes also, as bromide of benzol (a bad conductor 

 which is not decomposed by caustic potash or acetate of silver), 

 and also for nitro-compounds. 



* The same remark holds good for the anhydrides consisting of oxygen 

 and a metalloid (Table II.) and for N0 2 . 



t Phenate of potass (C 6 H 5 OK) is decomposed even by the current of 

 5 Bunsen elements, with brisk liberation of gas. 



