320 On the Height of Laghining Rods. 
will be the state of society when man’s physical powers are highly 
“exalted, and his physical condition highly ameliorated, with- 
out any slab cabin change in his moral habits and position. 
There is much reason to fear that every great advance in material 
civilization aay some moral and compensatory antagonism ; 
but however this may be, the very indeterminate character of the 
problem is a warning to the rulers of nations to prepare for the 
contingency by a system of national instruction which shall 
either reconcile or disregard those hostile influences under which — 
the people are now prnshibe 2 lack of be oes 
; Art. XXV.—On the proper Height of ‘Lightning Rods ; 
‘3 Exu1as Loomis, Professor of Mathematics and Natural Philso 
phy in New York University. 
Nein. Read before the American Renae for the Advancement of Science at New : 
n, August, 1850. 
Tue rule prescribed by the French Academy of Science (and 
. copied into almost all works on electricity,) for determining the 
proper height of a lightning rod is that a rod will ponies a a é 
whose radius is equal to twice the height of the rod. A case re 
‘cently occurred in Tallmadge, Summit CONT. Ohio, whale 
appears to demonstrate that this rule is unsafe 
On the afternoon of July 27th, about six o'clock, there was a 
nied by a few flashes: ‘of: lightning. 
: nd was succeeded almost instant- 
ly by a loud report. In an ‘instant afterwards, a large pile of shav-_ 
ings ying on the west side of a carriage shop was found in full 
and were quite diy: and as no fire had bens used i in that vicinity 
for several. weeks, and no other mode is known in — which the — : 
shavings could have been ignited, it is inferred to nie: been 
cattsed by the electric discharge. The carriage \shop was fur- 
~nished with a lightning rod, and it was a matter sof. surprise that 
the fluid should have struck the ground so near#o'the rod. The 
top of the rod was fifty-nine feet high above the shavings; and 
the shavings were one hundred feet distant from a point cortical 
under the top of the rod. According to the rule above quoted, 
this rod should have afforded complete protection to a distance of 
one hundred and eighteen feet from its base; whereas the shav- 
ings were struck at a distance of one hundred feet, and that too 
where, being elevated only a few inches above the general level of 
the ground, they might be presumed to afford no poenliet attrac- 
= for the lightning. 
his 
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rod appears to have been constructed in accordance with — 
the usual rules. It is terminated by three points which are gilded a oe 
