on SOME CHEMICAL AGENCIES 0? ELi;CTIlICU'T. 33S 



titles of nitrous gas have beon long kept ; it did not aifpc* Changes pro- .-^ 

 «olutio^ of muriate of barytes ; and a drop of it placed uppn ^^i'dL hf ^atei-.^ 

 a polished plate of silver left after evaporation a black stain^ 

 precisely similar to that produced by extremely diluted ni- 

 trous acid. 



After these resnitsj I could no longer doubt that some . 

 saline matter existing in the agate tubes had been the source < 

 of the acid matter capable of precipitating nitrate of silyeFj^^ 

 and of much of the alkali. Four additional repetition.'^ of 

 the process, however, convinced me^that there was likewisa^ 

 some other cause for the presence of this last substance; 

 for it continued to appear to t]}.e. last, in quantities suffi- 

 ciently-distinguishable, and apparently equal in every casQ,. 

 I had nsed every precaution ; I had included the tubes iu 

 glass vessels out of the reach of the circulating air;^ all the 

 acting materials had been repeatedly washed with distillec^r 

 Tfater ; and no part of them in contact with- the ^uid had ' 



been touched by the fingers. .,.....■ 



The only substance which I could now conceive capabl9, 

 of furnishing the fixed alkali was the water itself, This^ 

 water appeared pure by the tests of nitrate of silver and, 

 muriate of barytes; brut potash and soda, as is well known^, 

 rise in small quantities in rapid distillations ; and the New- 

 River water, which I made use of, contains animal i\nd ve- 

 getable impurities, which it was easy to conceive might fnr- 

 nish neutral salts capable of being carried over in vivid 

 ebullition. 



To make the experiment in as refuied a form as poseibk^^ I 

 procured two hollow concs_of pure gold containing about 25 

 grains of water each, thoy were filled with distilled water,' 

 connected together by a moistened piece of amianthus which: 

 had been used in the former experiments, and exposed to the 

 action of a Voltaic battery of 100 pairs of plates of copper 

 and zinc of six inches square, in which the fluid Avas a solu- 

 tion of alum and diluted sulphuric acid. In ten minutes the 

 watet in the negative tube had gained the power of givi^^ 

 a slight blue tint to litmus paper: and the water in the posi- 

 tive tube rendered it red. The process was continued for 

 14 hours; the acid increased in quantity during the whole 

 time, and tlie water became at last very spur to the taste* 



Th(? 



