rd 
354 Lightning Conductors in Ships. 
ships, in consequence of their masts, the only parts to which they 
can be attached, being exposed to chances of injury, to motion in a 
variety of ways, to frequent elongation and contraction, and to the 
necessity which frequently arises for removing the higher masts alto- 
gether, and placing them on deck. It was probably from these causes 
that the small flexible chains or links above mentioned were employ- 
ed. Such conductors, however, will probably, on examination, be 
found less applicable than fixed continuous lines of metal, and, in 
every point of view, inefficient substitutes for them. Their great 
want of continuity, as well as their want of mass and surface, is very 
unfavorable to the transmission of severe explosions, the electri¢ mat- 
ter becoming sensible at the points of junction, as is evident by the 
sparks which appear upon them at the time of the discharge, so that 
"in some instances they have been actually disunited : they are like- 
wise objectionable as being liable to every species of injury incident 
to a ship’s rigging, and much difficulty is experienced in keeping 
them in their position, and unbroken, more especially during gales of 
wind, and at night, when the ship is under sail, and when it is per- 
haps required, as is already observed, to remove some portion of the 
higher masts. It has therefore been long considered desirable to ap- 
ply, if possible, a permanent conductor, which should be always in 
its place, and ready for action; and various attempts have been made 
and suggestions advanced, at different times, to apply fixed lightning 
conductors in ships, as the subject from time to time has demanded 
further consideration. 
14. To protect a ship effectually from damage by lightning, it i 
essential that the conductor be as continuous and as direct as poss 
ble, from the highest points to the sea—that it be permanently fixed 
in the masts, throughout their whole extent, so as to admit of the mo- 
tion of one portion of the mast upon another; and, in case of the re- 
moval of any part of the mast, together with the conductor attached 
to it, either from accident or design, the remaining portion shou 
still be perfect, and equivalent to transmit an electrical discharge Int 
the sea. 
15. To fulfil these conditions, pieces of sheet copper; from 
eighth to one-sixteenth of an inch thick, and about two feet long, 
varying from six inches to one inch and a half in breadth, may be 
inserted into the masts in two lamine, one over the other ; the weed 
or joints of the one being covered by the central portions of the other. 
The lamine should be rivetted together at the butts, so as t a 
one- 
and 
