I 
202 Mr. Morgan’s Qbjervaiions and Experiments on 
ftanced fimilarly to the acids in the preceding experiment, 
were attended with fimilar, but not equal effects, becaufe, in 
confequence of the inferiority of their conducing power, it was 
neceflary to make the line through which the charge palled 
confiderably (barter. 
4. The brilliancy or fplendor of the elegtric fluid in its 
paflage through any body is always increafed by leflening the 
dinienhoos of that body. I would explain my meaning by fay- 
ing, thatafpark, or the difcharge of a battery which we might 
fuppofe equal to a fphere one quarter of an inch in diameter, 
would appear much more- brilliant if the fame quantity of fluid 
is compreiied into a fphere one -eighth of an inch in diameter. 
This obfervation is the obvious confequence of many known fads. 
If the machine be large enough to afford a fpark whole length 
is nine or ten inches, this fpark may be been lbmetimes forming 
xtfelf into a brufh, in which flate it occupies more room, but ap- 
pears very faintly luminous. At other times the fame fpark may 
be feen dividing itfelf into a variety of ramifications which (hoot 
into the furrounding air. In this cafe, likewife, the fluid is. 
diffufed over a large furfp.ce, and in proportion to the extent of 
that furface, fo is the faintnefs of the appearance. A fpark, 
which in the open air cannot exceed one quarter of an inch in 
diameter, will appear to fill the whole of an exhaufted receiver 
four inches wide and eight inches long. But in the former 
cafe it is brilliant, and in the latter it grows fainter and fainter 
asthe frze of the receiver iticreafes. To prove the obfervation, 
which I think may be juftified by the preceding fadts, I made 
the following experiments. 
exp. viii. To an infulated hall, four inches in diameter, I; 
fixed a filver thread, about four yards long. This thread, at 
the end: which was remotefl: from the ball, was fixed to another; 
c infulated 
