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longeft, many feet, in length. When thofe jars 
were difcharged through the iron bar before-men- 
tioned, together with a fmall chain, three quar- 
ters of a yard in length ; the whole cha’in was il- 
lumined, and covered throughout with beautiful 
rays, like bridles, or golden hair. Having placed 
a large jar in contact with my prime condu&or, 
I affixed to the coating of it an iron chain, which 
1 alfo connected with a' plate of metal, on which 
I intended to make the difcharge by my dif- 
charging-rod, tab. xiii. fig. 9-. This done, I 
hooked another chain, much longer, and of brafs, 
to the oppofite fide of the jar, and brought the end 
of it within eight inches and an half of the 
metal plate. In contaft with this end, I laid a 
fmall oak-ftick, eight inches long, which I co- 
vered with faw-duft of fir-wood. On making 
the difcharge upon the plate, both the chains were 
luminous through their whole lengths ; as was 
alfo the faw-duft, which was covered by a ftreak 
of light, making a very pleafing appearance. I 
repeated the experiment feveral times. Perhaps, 
if I had ufed a bar of iron, inftead of the chain 
firfl-fpoken of, there might have been no light 
upon the fecond chain, or upon the faw-duft, ef- 
pecially as the eleftricity had half an inch of air 
to pafs through, before it reached the end of the 
ftick. But from this experiment may, I think, be 
inferred, the neceftity of making the condudlors, 
ere&ed as a fecurity to buildings, 6tc. from the 
damage of lightning, both of the beft materials, 
and of a very fufficient fubftance ; and, for this pur- 
pofe, perhaps nothing will be found fo proper as 
