Nito El<ilric<tl or Galvanic -Apparalus. 189 



mer earperiment, a quantity of gas arofe from both wires> but in the grcateft quantity frona 

 that conneded with the filver. In a few minutes a fine red line, extending fome way 

 upwards, was perceived at the extremity of the zinc wire ; this increafed, and in a (hort 

 time the whole fluid below the point of this wire became red; the fluid, however, above 

 the filver wire, looked of a deeper blue than before, the flight tinge of purple being 

 deftroyed. 



Experiment 3. I next filled the tube with diftilled water, tinged with the tinflure of 

 Brazil wood; it was no fooner placed in the circle of communication, than the fluid fur- 

 rounding the filver wire, particularly towards its extremity, became purple, and this tinge 

 increafed fo fall, that the whole fluid furrounding this wire, and occupying the upper 

 part of the tube, foon afiumedas deep a colour, as could" be produced by ammonia. 



The portion of the fluid in conta£l: with the zinc wire became very pale, and almoft 

 colourlefs, nor could the purple tinge extend below its upper extremity. From thefe ex- 

 periments it would appear, that an acid, probably the nitrous, is produced at the wire 

 proceeding from the zinc, and an alkali, probably ammonia, at that in contaft with the 

 filver. Thefe fa£ts fufficiently explain the aftion upon the filver wire, and the nature of 

 the whiiifli cloud proceeding from it, and afterwards becoming purple. When lime- 

 water was employed inftead of common, or diftilled water, the wire was likewife a£ted 

 upon, but in a lefs degree, and the cloud had at firft an olive colour, exadlly refembling 

 the precipitate of filver by lime-water. 



The quantity of filver diflblved or corroded, if I may ufe the expreflion, in thefe experi- 

 ments, was very confiderable, and where common, or diftilled water had been employed, 

 a fmall portion of it remained in folution, which was difcovered by the addition of the 

 muriatic acid. Indeed a much larger quantity would probably have been fufpended, had 

 it not been for the alkali generated at the fame time, and which manifeftly produced a 

 precipitate at, or near, the upper extremity of the zinc wire, where after a certain time, a 

 dark zone or ftratum was always formed. 



Experiment 4. It is a well known fa£l:, that hydrogene gas when heated, or in its nafcent 

 flate, reduces the calces of the metals ; I expected, therefore, that by filling the glafs tube 

 with a metallic folution, I might be enabled to feparate the hydrogene from the oxigen 

 gas, and thus procure the latter in its fimple or pure ftatc. With this view the tube was 

 filled with a folution of the acetite of lead, to which an excefs of acid was added, to coun-- 

 teraft the effefts of the alkali. When the communication was made in the ufual way, no 

 gas could be perceived, but after a minute or two, fome fine metallic needles were per- 

 ceived at the extremity of the wire connefted with the filver. Thefe foon increafed, and 

 aflumed the form of a feather, or rather, that of the cryftals of the muriate of ammonia. 

 The lead thus precipitated was perfedlly in its metallic ftate, and very brilliant ; a little gas 

 efcaped from the wire connefted with the zinc, and it was confiderably corroded as ufual. 



A.folution of the fulphate of copper was next employed, and with the fame refult, the 

 4. copper 



