EXPERIMENTS ON THE ELECTRIC PILE. 17"? 



often inches in diameter, and eight pairs in height, by placing Pile of ten inches 

 four of each metal together as one plate, they being exactly m diameter » 

 fquare, and their furfaces very fmooth, that they might be in 

 clofe contact ; and then of five inches in diameter, and thirty- Another of five. 

 two pairs in height. The power of the higher pile greatly The powers of 

 exceeded that of the larger. In Auguft, Dr. Van Marum jJ^JfSIfr 

 had fu fed completely into globules five inches of the iron wire height, than on 

 mentioned above, and made feven inches red-hot, with this their diameter » 

 pile. 



The number of pairs of metal being increafed, the effect Effects not in^ 

 was not ; fifty pairs producing lefs than twenty-five, by ^ ^ t ^ e pr0 * 

 which nine inches of the fame wire were melted when Pro- height, when 

 fefTor Pfaff was prefent in November. This they afcribe to J**^**. 

 the moifttire being too much preffed out of the pieces of becaufe too much 

 pafleboard by the weight of fo many plates of metal a line and fluid 1S Puffed 

 a half or two lines thick; as the upper twenty-five pairs, 

 being taken off, had as much effect as before, while the lower 

 twenty-five had not half the power. In confequence they On this account 

 divided the pile into four, containing together HO pairs. [Jj e d ?Hj^ uld 

 The plate of copper, placed under and connecting the two feveral, commu- 

 piles that were infulated, had a rim, that the folution preffed mating with 

 out of the pafleboard might remain in it, and not wet 

 the infulafing cake, and deflroy the infulation. Thefe 

 two piles, containing fixty pairs fomewhat thinner than the 

 others, when not connected with the other two, made fix 

 inches of the wire red-hot. The other two piles, containing 

 fifty pairs, made eight inches very red, and fufed great part • 



of this length. This difference was afcribed to the pafle- 

 boards not being fufficiently moiflened in the former inflance. 

 The four piles connected together made twelve inches of the . : ■ 

 wire red-hot. 



On taking fparks repeatedly at each extremity of the con- p fitive and ne- 

 nedted piles, by means of a wire communicating with a bafin gative fparks di4 

 containing quickfilver, no difference between thofe of the 

 pofitive and thofe of the negative electricity could be dif- 

 cerned. Whether iffuing, or entering, they appeared ra- 

 diating, when iron wire was employed; which the experi- 

 mentalifis afcribe to the combuftion of the iron, for when a 

 wire of platina was ufed, no rays were perceptible in the 

 fparks of either electricity. Sometimes the communication 

 was made by means of a needle, faflened to the flender wire 



Vol. I. — March. X which 



