METALLIC WIRES BY ELECTRICITY. 457 
This piece of wire had therefore been rent asunder lengthways. 
The same was observed on the piece of wire about 1 line in 
length, which had been left in the inner clamp. Its diameter at 
different parts, measured from the clamp toward the point, was 
0°059 line. 
0013 ©... 
0°009 
0°005 
Experiment 29.—A platina wire, 0°042 line thick, was made 
incandescent by the quantity of electricity 8 contained in 3* 
jars, and was shivered to pieces by the quantity 12. A riband- 
like piece was at one end evidently torn off lengthways. Under 
the microscope, the thickest part of this end was found to be 
0°043, and the thinnest part 0°018 line in thickness. A wire 
of the same thickness, which was shivered by the quantity of 
electricity 12}, contained in 4* jars, yielded a piece, one end 
of which appeared jagged. We have here therefore proofs of 
the splintering of wires in the direction of their axes, which 
is quite incompatible with the assumption of a partial melting of 
the wires, by aid of which Van Marum endeavoured to explain 
the falling to pieces of the wirest. Even the superficial melt- 
ing which occasionally takes place, can be altogether avoided by a 
careful increase in the amount of charge. 
The following experiments were made with wires placed in 
the middle of a bell-glass 7 inches high and 5 inches wide. 
Experiment 30.—A platina wire, 19 lines long, radius 0:0258, 
was made incandescent by the quantity of electricity 12 from_ 
5 jars. The quantity 17 split it into a number of small pieces, 
on which no trace of fusion could be observed. 
Experiment 31.—A copper wire, 18 lines long, radius 0:0253, 
was incandescent with the quantity of electricity 23 from 5 jars. 
With the quantity 27 it was torn short off from the outer clamp, 
and at several lines distance from the inner clamp, and converted 
into pieces which partly showed the bends produced by former 
discharges. 
Experiment 32.—A silver wire, 17 lines long, radius 0:0264, 
was made incandescent by the quantity of electricity 22. With 
the quantity 24 it was torn short off from the inner clamp and 
split into pieces, on the outer clamp a piece about a line in 
length remained. 
+ Beschreibung, u. s. w. Erste Fortsetzung, S. 12. 
VOL. IV. PART XV. 16 Zhe 
