74 Partial Fusion of Metal Inj the Electric Discharge. 



your Magazine of March 1805, under the title of *' A new 

 Electrical Phsenomenon, communicated by a Correspon- 

 dent." In these experiments^ which were chiefly made 

 with a shilling, I could not reconcile the idea of a fusion 

 taking place, the force em])loyed heins; so very small : there 

 is, however, no doubt but this is a fusion both on the part 

 ,of the piece and the coating of the phial. 



Beinji induced to make these experiments with a greater 

 degree of accuracy and observation, I began with a piece of 

 monev, as stated in my former paper : it is there said, " I 

 sometimes observed a small hole in the coating where the 

 piece was taken from :" I find that this is made at every dis- 

 charge of the jar, whether the shilling is interposed or not. 

 On examining this hole (which is just perceptible to the 

 naked eye) with a microscope, I observed the coating cu- 

 riously melted, very minute glf»bules of the melted metal 

 being scattered around it in every direction. Sometimes, 

 when the jar is charged very highly, and the piece inter- 

 posed, several of these holes are made, in each of which 

 there is the same appearance. A small white spot, encom- 

 passed with a brown ring, is likewise observed on the shil- 

 ling, which bears evident marks of fusion, though in a less 

 degree than the tinfoil of the jar. 



On passino: twelve successive discharges through a shil- 

 lino-, the surface became quite brown for about half an inch 

 in length and two lines in breadth. This colour was not 

 permanent, but easily rubbed off with the finger. The white 

 spots, however, made at every discharge remained, and seemed 

 to be indented on the surface. It is somewhat remarkable, 

 that in all these experiments the effect on that side of the 

 piece which was next the coating of the jar was scarcely vi- 

 sible, though the tinfoil was melted as before. This favours 

 rather, I think, the idea of a single electric fluid. In cop- 

 per, this effect seems to partake more of a calcination or ox- 

 idation ; as the part w here the discharge was made through 

 was always white, though still encompassed with the brown 

 ring. 



From a number of trials it appears that this effect is 



scarcely, if at all, visible on thin plates of iron. Though 1 



4 ■ have 



