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trying whether it would conduct electricity, 1 found 
it tranfmitted the fmalleft fhocks, to a confiderable 
diftance; and, what appeared very remarkable, the 
path of the explofion was luminous all the way, and 
feemed to conlift of a prodigious number of fmali 
feparate fparks, fcattered to a great diflance, exhi- 
biting fuch an appearance as would be made by 
firing gunpowder lcattered carelefsly in a line. The 
explofion very much refembied the firing of a fquib. 
To compare it to another eleCtric appearance, it 
was like the explofion patting through a thin fur- 
face of gilding. 
I imagine that, though I could net perceive any 
interruption in this white coating, not even by the 
help of a microfcope, it muff, in faCt, have been full 
of interfaces, and the eleCtric fparks could only be 
vifible in pacing from conducting particle to 
another. 
In this experiment, I often got pieces of glafs very 
imperfectly covered, with intervals in the white 
coating very large and vifible j but, though I expofed 
the fame pieces of glafs to catch more of this mat- 
ter, I never could get a coating of it fo thick, but 
that, in tranfmitting the electrical explofion through 
it, it exhibited the fame luminous appearance, as if 
there were interfaces in the circuit. 
I got the fame matter from oil of turpentine, and 
oil of olives ; but not from bees-wax, or fpermaceti 
oil ; perhaps not from any animal fubftance. 
In order to obferve the progrefs of this incrufta- 
tion, I poured oil of turpentine on fome flat pieces of 
glafs, and burnt them on an iron plate, in the open 
fl re, the heat being moderate but the effeCt was a 
black 
