si6 Chemical Effect of Galvanic EUBricity. 



gas, it was diminlftied very greatly, and a folutlon of fulphuret of potafli, after having ab- 

 ftraftcd the excefs of oxygen gas, left only a fmall bubble of azotic gas, which may be 

 * traced to the oxygen gas employed to effedl the combuftion. 



8. A folution of cauftic vegetable alcali, being expofed in a fimihir manner, the ga» 

 produced was pure hydrogen gas. Durinj^the procefs, the furface of the rpercury became 

 covered with a bhckirti film, efpecially at its edges where it was in contadi with the glafs 

 tube. The black matter, however, was confined to the furface of the mercury, and was 

 not generated at the fame part of the tube at which gas was produced, viz. in conta£t witTi 

 the platina wire. It ftill occurred even on ufing mercury which had been carefully 

 diftilled fpr the purpofe. 



The two laft fa£ls are the mod curious that have occurred in the courfe of my ex- 

 periments. In experiment 7, the volatile alcali was certainly decompofed, for had the 

 hydrogen gas proceeded from the decompofulon of water only, oxygenous gas would alfo 

 have been obtained. Into what new combination does the azote, in this cafe, enter ? It i* 

 not improbable that at the fame inftant both water and ammoniac are decompofed; that 

 the hydrogen of both is converted into gas ; and that the oxygen of the water, uniting 

 with the azote of the alcali, compofes nitric acid, which, combining with the ammoniac, 

 produces nitrate of ammonia. The deftru£tion of the vegetable alcali is not lefs certain. 

 From the 8th experiment we derive a fufficient proof that it contains hydrogen. Azote 

 is probably another of its conftituents, but is prevented from appearing in the gafeous ftate 

 by its union with oxygen, evolved, at the fame inftant, by the decompofulon of a portion of 

 water. Thefe fuggeftions admit of being verified by a careful examination of the alcalis, 

 after expofure to the influence of galvanifm ; and a third component of the vegetable 

 alcali will perhaps be found in the black precipitate above defcrlbed. I have not been 

 inattentive, even hitherto, to thefe points ; but the minutenefs of the quantities fub- 

 xnitted to experiment prevents me from fpeaking decifively, and I choofe rather to referve 

 myfelf for the refults of experiments now going on, than to incur the rifle of being 

 f , forced to retraft a hafty aflcrtion. In the mean time, I fend you thefe particulars of un- 



finifhed experiments, becaufe thofe who are praftically engaged in inveftigating the pro- 

 perties of galvanifm may derive, from a communication with each other through the 

 medium of your Journal, fome of the advantages of perfonal Intercourfe and co- 

 operation. 



' I am refpeftfully, 

 SIR, 



Your obedient 



humble fervant, 



WILLIAM HENRY. 



Dtfcription 



