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MOLESWORTH'S POCKET-BOOK
Telegraph Construction, by R. 8. Brough.
Iron Wire.
B. W..G. Diameter in inches. Weight per yard in pounds. Breaking strain of soft iron wire in pounds. Ratio of resistance to that of No. 1 wire.
i 0-300 0-6875 4000 1-000
2 0-280 0-5990 3400 .1-148
3 0-260 0-5165 2900 1-331
31 0-250 0-4800 2700 '1-440
4 0-240 0-4400 2500 1-562
5 0’220 0’3700 2200 1-860
5i 0‘210 0-3409 2000 2-041
6 0-200 0’3056 1800 2-250
1 0185 0-2615 1520 2-630
8 0-170 0-2210 1200 3-114
9 0-155 0-1836 950 3’746
9| 0-149 0-1704 900 4*054
10 0-140 0-1497 820 4-592
11 0-125 0’1195 650 5-760
12 0-110 0-0924 510 7*438
124 0-105 0'0852 450 8'163
13 0-095 0-0705 400 9’972
14 0’085 0-0551 350 12-457
15 0-075 0-0429 300 16'000
16 0-065 0-0322 200 18-367
17 0-057 0'0284 150 21’302
Note.—The resistance per mile of No. I wire is about
5 ohms at 80° Fah.