PERFORATIONS OF PAP^R BY ELECTRICITY. 



177 



Kendal in his progress northward to Edinburgh and Glas- 

 gow This gentleman observed, that he had reason to sus- 

 pect the accuracy of the foregoing statement ; for, when he 

 undertook to perforate a slip of card paper by an electrical 

 discharge, he invariably found but one bur, arid this appeared 

 on the side of the card, which was connected with the nega- 

 . tive surface of the -battery. In consequence of this renv-irk, 

 the gentleman was asked, if the appearance was the same 

 when the discharge was made from the negative to thi* . 6si- 

 tive side of the battery, as well as wh& it passed, in the oppo- 

 site direction, namely from the positive to the negative side. 



To this question Mr. Webster replied ingenuously, that 

 he had always made the experiments in the latter manner; 

 and my predilection for the idea of a double current induced 

 me to obviate, or at least to weaken the objection, by re- 

 marking, that, the positive current being pm in motion be- 

 fore the negative fluid, it acquired a preponderance, which 

 enabled it to drive the paper in the direction of its own 

 course, and consequently to raise a single bur, on the side 

 of the card that was connected with the negative surface of 

 the battery. I moreover observed in addition to the last re- 

 mark; that, if the preceding reply to Mr. Webster's objec- 

 tion had truth for its foundation, the place of the bur might 

 be removed to the contrary side of the curd by inverting the 

 experiment, so as to give a preponderance to the negative 

 current; which would then drive the paper before it, and 

 form an elevated rim on that face of the slip, which was con- 

 nected with the positive surface of the battery. 



The want of facts, which is apparent in this discussion, The method 



determined me co repeat the experiment with the variations P ro i' os '** foi 



. , , ... , , , repeating the 



and under toe conditions, that had been pnesenbed by my- experiment. 



self. For this purpose 1 procuredsevejai slips of card pa^er; 

 that were cut accurately into the shape ot right angled pa- 

 rallelograms ; and all of them had both their face- divided 

 diagonally, each by two diameters intersecting in the centre 

 of the plane. Pieces of tinfoil were then reduced to the 

 figure and size of the triangles, which had the shorter sides 

 of the parallelograms for their bases. One triangle m each 

 side of a slip, was covered in the next place by one of these 

 metallic coatings; the pieces of tinfoil being so disponed as 



to 



