1054 Mr. henly’s Obfervatiom 
ratios being made a part of the circuit, a charged bottle 
of a proper fize was difcharged through it: when the 
charge palled along the furface of the card from the end 
of that wire into which it was difcharged, till it came to 
the end of the other wire, and there pierced a hole 
through the card, palling by that wire to the negative 
fide of the bottle; and this happened whether the bottle 
was charged pofitively or negatively* A learned and in- 
genious correfpondent of mine, the honourable Frede- 
ric Christian mahling, counfellor of ftate at Copen- 
hagen, has improved this experiment, by firft painting 
the card in a line about half an inch broad on each fur- 
face with Vermillion. The charge palling in this line 
(the card being previoully well-dried) Ihews its palfage 
by a black mark on the Vermillion, the mark being on 
one fide of the card when the bottle is charged pofi- 
tively, and on the other fide of it when the bottle is 
charged negatively. To which I would add, that a line 
of light is feen upon one furface of the card through the 
whole fpace between the ends of the wires in one cafe, 
for inftance, when the bottle is charged pofitively. But 
no light is feen in the other cafe, that is, when the bottle 
is charged negatively, till the electricity burfts a hole 
through the card to get at the wire which is in contad 
with 
