APPENDIX J. DATA RESPECTING THE SECTIONAL AREA OF METAL REQUISITE FOR LIGHTNING CONDUCTORS.
Reading edition
(N.B.—In order to avoid confusion, all areas of iron have been reduced to ⅙th of their actual sizes, so that virtually tables I. and II. may be regarded as giving all details for copper—but the metal is specified in each case.)
TABLE I.—LIST OF METALS MELTED.
Material Form Size Remarks
Diameter. Area of Copper.
in. in.
Copper Rod ·35 ·10 Duprez, App., p. 92
Copper Rope ·31 ·075 At Nantes, Callaud’s Traité, p. 89
[6]Not Specified. Rope ·07 At Carcassone, Callaud’s Traité, p. 89
Iron Rod ·03 Harris on Thunderstorms, p. 109
Brass Rod ·20 ·03 Duprez, App., p. 92
Copper Rod ·13? ·01? Sullivan, App., p. 195
TABLE II.—REMARKS RESPECTING DIMENSIONS.
Material Form Size Remarks
Diameter Area of Copper.
in. in.
Copper Rod ·61 Trinity House smallest, App., p. 183
Copper Rod ·75 ·44 Will carry any flash, Harris on Thunderstorms, p. 115
Copper Rod ·50 ·20 Never yet failed, Faraday, App., p. 89
Copper Tube ·20 War Office smallest, App., p. 70
Copper Tape ·19 Gray & Son’s smallest, App., p.
Iron Rod ·16 Never affected, Franklin, App., p. 52
Copper Any form ·11 Recommended by Phin, App., p. 103
Iron Rod ·11 More than sufficient, Gay Lussac, App., p. 58
Copper Rope ·38 ·11 Recommended by Callaud, App., p. 104
Copper Tape ·09 Freeman & Collier’s smallest, App., p. 10
Iron Rod ·08 Never known to be melted, Pouillet, App., p. 62
Iron Rod ·08 Should not be less, Henry, App., p. 99
Copper Rope ·39 ·06 Carried off heavy discharge, Callaud Traité, p. 89
Iron Rod ·06 Recommended by Callaud, App., p. 104
Iron Rod ·06 Recommended by Mohn, App., p. 107
Copper Rod ·25 ·05 Recommended by Mohn, App., p. 107
Iron Rod ·04 Recommended by Phin, App., p. 103
Copper Rod ·20 ·03 Recommended by Zenger, App., p. 106
Iron Rope ·02 Recommended by Mann, App., p. 108
Iron Wire ·01 Sufficient for any house, Preece, App., p. 101
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DIMENSIONS OF LIGHTNING RODS—COPPER.
Partly extracted from the Appendix at the pages quoted, and partly compiled from specimens collected by the Conference, and from trade circulars.
Pattern Diameter Breadth Thickness Superficies Area Weight per foot Remarks, and References to Appendices.
Inches Inches Inch Inches Inch oz.
Tube Ext. 1½ Int. 1 ¼ Ext. 4·71 Int. 3·14 ·98 60 Sir W. Snow Harris (49)
Hemicylinder 1½ 3·86 ·88 54 Trinity House, Mains (183)
Hemicylinder 1¼ 3·21 ·61 37 Trinity House, Branches (183)
Tape 3 3/16 6·38 ·56 34 Freeman & Collier’s largest (10)
Tube Ext. 1½ Int. 1¼ ⅛ Ext. 4·71 Int. 3·93 ·54 33
Rod ¾ 2·35 ·44 27 Faraday preferred this to smaller (89)
Tape 3 ⅛ 6·25 ·37 23 Gray & Son’s largest (7)
Tube Ext. 1 Int. ¾ ⅛ Ext. 3·14 Int. 2·36 ·34 21
Tape 2 ⅛ 4·25 ·25 15 Sanderson’s largest (23)
Tape 1½ ·15 3·30 ·23 14
Rod ½ 1·57 ·20 12 War Office (70) Sir W. Snow Harris (49)
Tape 1½ ⅛ 3·25 ·19 12 War Office (70) “Smallest desirable” Gray & Son (7)
Tube Ext. ⅝ Int. ⅜ ⅛ Ext. 1·96 Int. 1·18 ·20 12 War Office (70)
Tape 2½ 1/16 5·12 ·15 9 J. Davis & Son (14)
Rope (49 square wires) ⅔ 10·78 ·15 9 Pennycook & Co.
Tape 2 1/16 4·12 ·13 8
Tape 1 ⅛ 2·25 ·13 8 Phin, of New York (103)
Rope (49 wires) ½ 8·00? ·10 6 {Massingham (15) Newall’s Rope
Tape 1½ 1/16 3·12 ·09 6
Tape ¾ ⅛ 1·75 ·09 6 Freeman & Collier’s smallest (10)
Tube Ext. ⅞ Int. 13/16 1/32 Ext. 2·75 Int. 2·55 ·08 5
Rope (36 wires & hemp centre) 7/16 5·00? ·08 5 J. Davis & Son (14)
Spratt’s Patent Plait (20 wires) 1⅓ 4·52 ·08 5
Tape 1 1/16 2·12 ·06 4
Rope (49 wires) ⅜ 6·00? ·06 4 Newall’s Rope
Tape ⅝ 1/12 1·42 ·05 3 Sanderson’s smallest (23)
Spratt’s Patent Plait (14 wires) 1 3·16 ·05 3
Hart’s Plait (13 copper wires and 1 zinc one) 3·08 ·05 3
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