262 Some Account of Electrical Experiments. 



site chemical effects when its influence is transmitted from a 

 metal to water, to those which are invariably attendant on its 

 transmission from water to metals. 



In pursuing these experiments, M. De Nelis fastened two gold 

 wires on a plate of glass by means of sealing-wax ; the wires 

 were disposed in a line, with their proximate ends in close con- 

 tact with the surface of the glass, and at the distance ot half a 

 line from each other. A drop of oil being placed over the inter- 

 val, '^and a current of sparks passed from one v.ire to the other, 

 it was found that after fifty turns of the machine, a small hole 

 similar to the impression of the angle of a diamond, was made 

 in the glass beneath the negative wire, but no effect of a similar 

 kind was to be observed about tlie positive wire. 



I have repeated this experiment with a slight variation ; the 

 gold wires were attached to a plate of glass, cut in the form of 

 the letter V. The wires were fastened to the glass near its edges 

 with a separation between them of an eighth of an inch, which 

 was placed very near the lower a])ex of the plate ; the glass 

 plate being immersed in a wine glass fdled witii olive oil, the 

 effect is a little assisted by the pressure of that fluid ; the sparks 

 were received from the conductor by a large insulated ball, 

 placed at an inch distance from it, and connected with one of 

 the gold wires; the other being in communication with the 

 ground. With one of my cylinder machines 57 { inches in cir- 

 cumference, the effect was very conspicuously ol)tained in a few 

 turns ; and by continuing the sparks a few minutes, a deep ex- 

 cavation was made beneatli the negative wire. 



An experiment very similar to this was made some years ago 

 by my friend Mr. Crosse, who has repeatedly shown it to me 

 and others; he employed water instead of oil ; and having in 

 view only the decomposition of the water, and the perforation 

 of the glass, made the separation of the wires so small, that the 

 constant occurrence of the perforation under the negative wire 

 escaped his observation. 



It will be obvious to electricians, that the effect produced in 

 this experiment is very analogous to the perforated card in that 

 contrived by Mr. Lullin of Geneva, and which I have employed 

 with slight alteration as an illustration in the Elements of 

 Electricity, page 165, Experiment ()(). And it will probably 

 be generally admitted by unprejudiced observers, that the ex- 

 periment of M. De Nelis, and that of Mr. Lullin, evince very 

 distinctly the action of a material agent, moving from the posi- 

 tive to the negative wire: at least it is not at present easy to 

 account for their results in any other wav. 

 Leudon, Oct. 4, Itjlo. ' G. J. SiNGER. 



P. s. 



