TRANSACTIONS OF THE SECTIONS. • 
On Eleclric Cloch. By Alexander Bain. 
23 
0* me recent and remarkahh examples of the Protection affi^dcd hy 
Jfaaffic Condvriors against heavy strokes of Liyhtainy. By oir NVilliam 
S xow Habruv, FM.S. 
Tie possibility of guardins bua<iing 9 and other structures against the destructive 
(Jw* of lightning has been made a great question in practical science, from the 
tiae of Franklin to tht present day; and it is of considerable public iniportance, 
eesf the frequent damage which occurs to churches and other edifices by strokes 
Joining, to bring this question completely under the dominion of practical 
»iee. , , , - 
general principles which Sir W. S. Harris submitted as detlucible from 
ihinqniries to which he alluded are these:—If we imagine a ship or building 
senaist altogether of meUllic substances, it would certainly be secure from any 
by lightning, and for this simple reason, that what we call lightning is 
ih Hall of the electrical agency forcing a path through resisting matter, su^ ^ 
'll Of, and extricating with explosive and expansive force both light and heat m its 
When, on the contrary, it falls upon comparatively non-rcsisting bodies, 
'tA u the metals, then this form of lightning vanishes, and the discharge assumes, 
^ IIk metallic body be sufiicicutlv capacious, the form of a comparatively quiescen 
Our object should be therefore In defending any building or ship from 
'jilhuog, to bring Ae general mass lo Car as possible into that pa^iv^r comp^^ 
ht^Bou-reaUtinz state it would have supposing it a mass of inclal. This is m fact 
““Bagleand simple condition of such an applicatiou, without any reference wha^ver 
forces of attraction, or peculiar specific powers mmleaicd by certtun 
J^fcrtho matter of lightning, and which really do not exist. ThisBimple 
httsrtful mechanical arrangement calculated to render it practical and appJicaoie 
'“dlthe duties which tire general struciureof a ship, together with Us mnsts, has to 
now uDivcrenllv carried out in the navy with the most perfect success; so 
Jianage by lightning in thevesseU so fitted has for the last fifteen ycarsquite ceased. 
■^“Mtsure made complclely conducting bv capacious plnlcs of copper reaching fom 
points to the keel ; and are lied into one general connection •with tje 
ISKoftallic masses employed in the construction of the hull, and united > 
"'^ hcilU of copper passing through the keel and sides, with the copper expan e 
'’Wthcbouum and with the sea. It is quite impossible that a discharge of hgh - 
fall on the vessel in any place without being at once transmitted sa e j y 
^“ductoi's, not under the explosive form of lightning, but under the orm 
“ij^lwitliout explosion. , e 
.^author then laid before the Section certain remarkable instances of ships ot 
^.Myal Navy thus armed beinz struck bv powerful discharges of lightning on 
. %4l Navy thus armed being struck by powerful discharges of lightniu 
UaUons. in which the views he had been discussing were completely 
sub- 
on the general Nature and Baies of Electrical Attraction- 
By Sir \V. Snow IIaruis, 
ou tY. OAUW ■» —-— 
commencfed by a brief account of the tlieory of ele^aty 
• reach philovipherij, and then proceeded to uotice soine physi ... ■ 
invalidate this theory; amongst others, the electrical wn^^onot^ a 
body in a space nearly void of re-iistance, and *hich. • p y^jer 
<JUt«ree from cnndoctmg matter, nralntaineil a “"Je! 
^«;tumstnnces. Tire ambnr, by a careful process, had 
J ^electridty of a small sphere in an exhausted St 
hi %». la convSviug a charge to a common “w^ 
werl received into it. in cqua^ iael^Sc flu^ 
Vh*. being more analogies lo the tilling a vi^el ' 'I'Hp action of the 
M-til"'' condensation of au claslte fluid such asair. nhilosooher 
tiad the balance of torsion as employed by the 
next adverted to; here the author endeavoured to show that great 
