500 Prof. Marianini on the Currents produced by the 



distance, so to remove my doubt that some part of the dis- 

 charge might fall upon the neighbouring bodies instead of 

 the extremity of the metallic band upon which I intended the 

 spark to pass, I attached two long copper wires to the ex- 

 tremities of the said band, and I went to some meters distance 

 to discharge the jar ; but the effects upon the re-electrometer 

 were not different from those already observed. 



If these experiments do not serve to show that the current 

 of the Leyden jar passing through a metal causes in a neigh- 

 bouring metal an electric current by induction, they would 

 yet prove a very singular and unexpected property of the 

 discharge of the Leyden jar ; that I mean of dispersing itself 

 in part in the worst conductors, even after having begun to 

 traverse the best, since it must be said that the electric fluid 

 descending by the vertical band scarcely reaches the point 

 where this touches the wool or the sealing-wax, when a part 

 of it quickly passes through the wool itself, and finding the 

 band of lead underneath, a fraction of this part of the cur- 

 rent passes into the band itself which is under the wool, and 

 reaches the external coating of the jar by the shortest way ; 

 whilst the other fraction makes a much greater turn to traverse 

 the coil around the re-electrometric iron, and at length reach- 

 ing the wool from the opposite part, and there passing through 

 the confining stratum, rejoins the other part of the larger band 

 communicating with the external coating of the jar. That such 

 a dispersion and division of discharge does not take place, 

 seems proved by the experiments which I shall now describe. 



VI. I made the experiments of the preceding section, but 

 instead of laying the plate upon which the jar was discharged 

 upon the confining portion for the space of two decimeters, 

 I caused it to touch it only at a few points, bending it up- 

 wards at both sides ; and I observed that if that part of the 

 plate parallel to the under one was distant from the latter only 

 a few centimeters, the effects upon the re-electrometer were 

 still visible ; but when the distance was two decimeters, there 

 were no longer any deviations in the re-electrometer. 



Having again laid the said plate upon the confining stratum, 

 I cut in two the leaden band which communicated with the 

 ends of the re-electrometer, and I placed near, between them, 

 the sections, without their touching ; and this was done, be- 

 cause, if in discharging the Leyden jar a part of the current 

 were carried upon this plate, crossing the confining part, all 

 this portion must pass through the coil of the re-electrometer, 

 and thence produce much greater deviations than when the 

 band offered a continued conductor. But, on the contrary, 

 the effects in this case were nothing ; consequently, in these 



