]y3 PERFORATIONS OF PAPER BY ELECTRICITY. 



to make their bases coincide with the oposite ends of the card, 

 while their points fell upon the centre of the surface to which 

 they were pasted. This arrangement evidently formed an 

 intercepted conductor; which obliged the electric charge to 

 pass through the card paper in a right line perpendicular to 

 its oposite faces. Perhaps I may be blamed for giving a cir- 

 cumstantial description of a very simple contrivance; but 

 minuteness always appears to me absolutely necessary in re- 

 lating the manner of conducting an experiment. 

 Gener.il re;i;1t I made the discharge from the positive to the negative 

 not favourable s j^ e Q f tne battery in my first trial; in consequence of 

 to a dou&le J / ' 



currem. which two burs were raised at the centre of the card ; 



namely, a small one on the face connected with the positive 

 coating, which seems to have escaped Mr. Webster's notice, 

 and a second on the opposite side of the paper, to which 

 he directed his attention exclusively. This perforation 

 bore a strict resemblance to the holes that a punch makes 

 in a plate of metal, or other ductile substance; for I found 

 upon trial, when ' an instrument of this description was 

 driven forcibly through a card placed on a piece of soft 

 wood, or through a plate of lead fixed by nails over a hole, 

 the perforation made by it was furnished with two burs, 

 like those produced by the stroke of a battery. The pro- 

 minent ring surrrounding the upper orifice, where the 

 operation of the punch began, was small; but the rim on 

 the opposite or under surface of the card or lead was 

 comparatively large. The reason of this difference is too 

 manifest to require, an explanation; but the strict analogy 

 observable in the two experiments with the battery and 

 punch led roe to attribute. the perforation in the former 

 case to the action of the positive current alone. When the 

 experiment was inverted, and the discharge made from the 

 negative to the positive coating of the jars, no alteration 

 was produced; for the minute bur still kept its place 

 upon that side of the card which was connected with the 

 positive surface of the battery; and the large bur was 

 formed on the opposite side of the paper. 



The existence This result shows the futility of my remarks on Mr. 



«>/ a negative Webster's objection to a double current; for, if the 



ftniil is not de- . . ', , , v r i- »• c 4. 



monitrated by positive current produced the perforation in my first ex- 

 periment 



