The telegraph manual: a complete history and description of the semaphoric, electric and magnetic telegraphs of Europe, Asia, Africa, and America, ancient and modern.

522 ELECTRIC TELEGRAPH CONDUCTORS.
No. 10, zinc coated, broke at................ 925 lbs.
"." annealed "............... 875 "
Plain ".................1,050 "
" " not annealed "............... 1,300 "
Table 6.
In January, 1859, I tested, at the same establishment, some
wire manufactured for commercial purposes from the same
quality of bars, from which were drawn the samples tested in
the experiments of January and February, 1859. It will be
found to be of much less strength than the wire manufactured
for telegraphic purposes.
American. Swedish.
No. 6...................1,940....................2,020
7..........1,675..................... 1,640
8............ 1,550............1,430
SCALE AND WEIGHT OF TELEGRAPH WIRE.
The mode of measuring wire has not been uniform or based
upon any fixed standard. The two leading rules are the Birmingham gauge of England, and the Washburn gauge of
America. The former measures the wire by passing it through
a fixed opening, between parallel lines; the latter, by passing
the wire between steel bars, fixed at an acute angle resembling a very elongated v. The wire descends the opening until its diameter rests against the sides forming the isosceles
triangle, and the points marked upon the sides, gives exactly
the size of the wire. This gauge is a great improvement over all
other forms, because the fractionals can be given. If the wire is
10~ or 10l or 10-, the Washburn measure can indicate it exactly.
This novel improvement in measuring the diameter of any
sized wire is the recognized gauge of America, and is known
as the " Washburn gauge." The weight of the wire according to this scale is given in the following table:
Table 7.
WEIGHT OF IRON WIRE PER TWENTY FEET, BY WASHBURN GAUGE.
No. 1 weight.......4 lb. 2 oz. No. 8 weight......1 lb. 7 oz.
2 ".......3 8 " 9 "......1 " 2 "
3 ".......2" 15 " 10 "......... 14 "
4 ".......2" 8 " 11 "......... 10 "
5 ".......2" 5 " 12 "......... 9 "
6',.......1 14 " 13 "......... 6 "
7 ".......1 " 10 "
No. 7 weight of iron wire per mile,................430 lbs.
8 " _...........................375
9 " "............... 320
10 ", ".....................250
12 weight of copper wire per mile................... 176
1 1",................... 63
18 "................ 38