t8« Experiments with a new EleSrical or Galvanic Apparatus, 



clear underftanding of the terms we ufc. This pile gave us the (hock as before defcribed, 

 and a very acute fenfation wherever the fkin was broken. Our firft lefearch was direfted 

 to afcertain that the (hock we felt was really an eleftrical phenomenon. For this purpofc 

 the pile was placed upon Bennett's gold leaf cleftrometer, and a wire was then made to 

 communicate from the top of the pile to the metallic (land or foot of the inftruraent. So 

 that the circuit of the (hock would have been through the leaves, if they had diverged. 

 But no figns of eleftricity appeared. Recourfe was then had to the revolving doubler, 

 defcribed at page 95 of our prefent volume. The plate A was connected with the top of 

 the eleftrometer and the filver end of the pile i and the plate B and ball were made to 

 touch the top of the fyftem by an uninfulated brafs wire. The doubler had been previoufly 

 cleared of eleftricity by twenty turns in connexion with the earth. The negative diverg- 

 ence was produced in the eleftrometer. Repeated experiments of this kind (hewed that 

 the filver end was in the minus, and the zinc end in the plus ftate. 



In all thefe experiments it was obferved, that the aftion of the inftrument was freely _ 

 tranfmitted through the ufual condu£lors of eledVricity, but (topped by glafs and other 

 non-condu£tors. Very early in this courfe, the contafts being made fure by placing a 

 drop of water upon the upper plate, Mr. Carlifle obferved a difengagement of gas round the 

 touching wire. This gas, though very minute in quantity, evidently feemed to me to Irave 

 the fmcll afforded by hydrogen when the wire of communication was fteel. This, with 

 fomc other fadts, led me to propofe to break the circuit by the fubflitution of a tube of 

 water between two wires. On the 2d of May we, therefore, inferted a brafs wire through 

 each of two corks inferted in a glafs tube of half an inch internal diameter. The tube 

 was filled with New river water, and the diftance between the points of the wires in the 

 water was one inch and three quarters. This compound difcharger was applied fo that the 

 external ends of its wire were in contaft with the two extreme plates of a pile of thirty-Gx 

 half crowns with the correfpondent pieces of zinc and pafteboard. A fine ftream of minute 

 bubbles immediately began to flow from the point of the lower wire in the tube, which 

 communicated with the filver, and the oppofite point of the upper wire became tarniOied, 

 firft deep orange, and then black. On reverfing the tube, the gas came from the other 

 point, which was now loweft, while the upper in its turn became tarniflied and black. 

 Reverfing the tube again, the phenomena again changed their order. In this ftate the 

 whole was left for two hours and a half. The upper wire gradually emitted whitilh filmy 

 clouds, which, towards the end of the procefs, became of a pea green colour, and hung in 

 perpendicular threads from the extreme half inch of the wire, the water being rendered fe- 

 mi-opaque by what fell off, and in a great part lay, of a pale green, on the lower furface of 

 the tube, which, in this difpofition of the apparatus, was inclined about forty degrees to 

 the horizon. The lower wire of three quarters of an inch long, conftantly emitted gas, 

 except when another circuit, or complete wire, was applied to the apparatus ; during which 

 time the cmifTion of gas was fufpended. When this laft mentioned wire was removed, the 

 gas re-appeared as before, not inftantly, but after the lapfe of four beats of a half fecond 



clock 



