356 Lightning Conductors in Ships. 
pared with the copper links usually furnished to the British navy, te- 
gether with the necessary equivalent in copper or iron bolt, in order 
to obtain a conductor of the same mass. 
The resulting quantities in the last line at the bottom of the table, 
represent, with the exception of the proposed conductors, the masses, 
surfaces, and diameters of cylindrical metallic rods, supposed to ex- 
tend the whole length of the mast. Thus in column 2, we have the 
diameter and surface of a copper rod, containing 2423 cubic inches 
of metal, being an equal quantity of matter to that in the proposed 
conductors, and from which it is calculated. The sums, therefore, 
are not the result of the addition of the successive masts. e same 
may be observed in column 3; taking the equivalent in iron. , In the 
third and fourth columns, we have the mass and surface of a copper 
rod of half an inch in diameter, generally allowed to be adequate to 
any shock of lightning yet experienced: and, lastly, in column 4, 
we have the mass and surface in the conductors now furnished to the 
British navy ; which we find, as compared with the mass in the pro- 
posed arrangement, is only as 94.4 ; 2423. 
TABLE. 
Equivalent in |Mass and|Mass and 
Equiva- |an iron rod ; ta-|surface in surface in 
Proposed |lent in a | king ¢ onduct- | a copper | present 
conductors| copper jing powers on-|rodof $in| conduct 
SUCCESSION OF rod. ly as diam iameter.|__ O's 
* “MAsTs. ; 
5 5 | coe 6 
oO _ Oo oO soa o 12) 
gl elelaig¢]elelelelei¢ 
3 ei/se|ele4 oe ip tae 
a 25 |a\a 6) Oo) 2 |o |e |e 
oyal P cub.| sqr. ‘sqr.|cub.|  sqr. cub. | sqr. cub. sar 
sored 18 ft. 1 inch in. | in. | in. in. in. | in. | in. |i in. | In. 
lon wi ite 3 
fisting ach © 54| 1752] .56| 385] 216) 7701.12} 42] 343)10.5 171 
seath ars an ben thick. eS ee 
gallant-mast. ect ot fx popes 
Conductor 17 ft. long, 23 
wide; two lamine, 60 
one one-eighth of an in.| 95| 2040] .77| 493} 380| 986)1.54) 40] 32010 | 
thick, the other one-six- 
teenth. iit 
Top-m Rage He, ee aS 
Conductor 50 es ben 471 
4 in wide ; two] 600} 9600]1.1 |2070'2400| 4140/2.2 | 127} 942)19.2 
laminz, each one eighth 
of an in. thik i 
Conaactr 93. fe. ‘long; 876 
ee £64 in. wide ; two|1674/26784\1.38|4837,6696| 9675)2.76, 219 1753/57.7 
heh 
one pl 
—— 
— 
aoraigd 4 
3493\40176 1.2 T | 418/3358194 
Fd 
