85 AERIAL COLUMN AND AERIAL ELECTROSCOPE. 



next, what was the best insulating varnish to cover glass ; and 

 in their course I ascertained the different conducting faculty of 

 various bodies. 

 Conductors 12. The general results of these experiments were, that with 



ductors,"^°"' ''^^P^ct to the lesl conductors, the glass lubes vvitli water and 

 proper wires, when no chemical effect is produced in them, are 

 sensibly as good conductors as melafs. As to the insulating 

 faculty, I found, thai sealing wax, in which no spirit of wine 

 is added to make it softer, being laid on glass rods sufficiently 

 heated to melt it, is equal to the best other varnish ; lor when 

 placed on the extremities of the column, with the precautions 

 I have indicated (the want of which prsduce very remarkable 

 > phaenome a) these rods do not affect the divergence of the gold 



leaves. Lastly, I have given many details of my experiments 

 on intermediate bodies, showing that, in proportion to their con- 

 ducting faculty, each produces a determined degree of diminution 

 in the divergence of the gold leaves. 

 inentrpr^Jve a ^^' ^^^ ^^^"^® °^ ^^^^^ experiments affords such proofs of a 

 cuciilation of circulation of the electric fluid in the column when its extremi- 

 le uid. jjgg jjj.g connected together, and consequently of its motion, that, 



if Dr. Maycock had known them, he could not have had any 

 doubt of these effects. The circulation is in consequence of an 

 accumulation constantly tending to be produced on the positive 

 extremity, at the expense of the other. This tendency con- 

 tinues, though the extremities are connected together ; but the 

 electric fluid cannot accumulate on the positive, while a ^ooc? 

 conductor can transmit it instatitly to the negative ; whence it 

 also instantly returns to the positive, by the property of the 

 column. But if the intermediate body be an imperfect conductor, 

 the circulatiim is lessened; and some electrical signs remain at 

 the extremities. ' ' 

 I'he electrical 14. There is another set of my experiments, which might 

 ^cdonnotsud- j^^ve made Dr. Maycock doabt of the very ground of his sys- 

 tem. ' He has imagined a certain property producing the elec' 

 irical effects ; such, I suppose, as that pf the vmgnet ; which, 

 inconsequence, ought to did suddenly . If this were the case, 

 when a communication with the ground has changed the diver- 

 gences of '{he gold leaves, that communication being removed, 

 the same divergences ought to be suddenly restored ; but it is 

 far otherv/ise, as may be seen in Exp, 4, 5, 6, of the same paper. 



There 



