Herald of the times. [volume] (Newport, R.I.) 1830-1846, 1843-08-03

he liable 10 be fused, or broken in pieces !;
or MOI being able To convey the entire charge
this would be- apt to divide into several bran
ches and find its way 10 The earth by differ
ent routes.
As the metallic bars are usually sold in
detached pieces of few feet in length, il
becomes necessary TO unite them and to
insure perfect continuity by well fitted joints
is one Of. the most important principles Of
The whole. know %: no better joint Than
that made by Mr.. Griswold Of New Haven
it is the mor,icc and tenon joint. The pro-
lecling par, OF the end of one piece being
nicely fitted to a corresponding slit in the
end of another piece, and the two pinned
firmly together. Probably ingenious artists
"qunly good. The only essential point is,
parts OF one piece being in ultimate contact
with those Of The other in as large q surface
as possible.
DETERMINATIONS. The upper par, of the
rod should consist OF taperIng stem Of cop
Der, ending 10 one or more sharp points OF a
metal not liable to rust. II may be either
platina, SILVER, or gold. Grswold's rods
have their tips cootrd with gold leaf; but as
his il somewh hat lnblc TO wear off IN time, n
better method is 10 gid the points on copper
by the new eleciroiype process. Gold Is
the best conductor oi electricity Of all The
melnIs--far better than plal,na-and when
thu. permnnerily Incorporated with The cop
per points. nothing more eligible can be de
sired. ELECTRICITY thus furnishes the best
means OF securing us against us own irregu-
lariles. A sing 10 point only Is generally
"mployed in Europe, but in this country
three divcrging points are more common,
partly because they arc considered more
tasteful, and partly because II is supposed
advantageous to present points To the clouds
IN different directions. But there 10 some
reason TO believe that a single point has great
or efficacy than several, SINCE, as was men
toned IN another connexlon, II has been
found by experiment, that a conductor charg-
ed with electricity. will be so"ner discharged
by single point than by collection OF nine
points.
The lower part OF the rod should have on
Increased surface. either by enlarglng the
s2e Of lhe bar or by letting it end IN several
branches all terminating ~ sharp points. Aa
IRON, however. Is peculiarly liable to rust IL,
the ground, 1t j. especially necessary to pro-
rrci lhls part of the rod from corrosion, cl,h'
er by a thick coating Of black paint, or (whni
is be'teD by employing galvanized iron with
out paint.
4.-.4ppiicaiion. The efficacy of light
ning rod IL much increased by liz rising high
above The building. Even at the top of n
,pire, il is not sufficient that II project lit-
tie way above the spire for although It might
even ~ that case protect the spiIe itselt yel
It's power TO protect the oiher parts OF The
building would be very small. a long needle
rcld near charged conductor, viii readily
discharge the electricity II the thumb and
finger be applied to the remote end; but
if applied near the adjacent end, the con
dncung power will be greatly diminished.
| The experiment wns tried by DR.. Franklin
aud the necessity Of lightning rods rising
high above buildings inferred from II. a
similar experiment was afterwards tired bv
Lord SlaDhopc, which led h IN 10 similar con
illusions. The rule, therefore, that hghf'
n,ng rod ,oW protect a space ervy trdy f'oiee
ihe erieat Of height a6ore the building, re
quires, N its application, careful considera-
ton OF the circumstances. house has
bu, one chimney and the rod is attached Ia
fhal, there being no other prominent object
on the root, the height OF the rod may be
recknned from the ridge at the highest part
of the roof Thus. If the rod rises fifteen
fee, above the ridge, it will protec, space
every way from ii of thirty feet But II there
are several chlmneys. it Will be necessary Il
reckon The hclgh, of the rod above the eve
Of The tops Of the chnneys. In each case
1t will generally be better to employ two o
more rode, than TO attempt TO cover the Who'll,
space by single stem of great height. II
f.. has thn In tn hnt
chimney as has been before reiparked) re
qures special protection. When the build
,"g Is not of very great extent. It vii b'
sufficient To have siugle conductor leau Il
I The earth, while one or more separate stems
rise from 1t to guard points Of the house pc
cuarly exposed. IN many cases, however
it will be more eligible TO let separate con
ductors descend to the earth from two dis
tant chmncys by the shortest possible route
than to attempt To connect several stems Will
a common conductor.
Since it is acknowledged that houses will
several chImneys, may require more than
single stem To rise above the ridge OF The
building, it becomes question, tchdf numbe
Of such projections from the main rod shal
be recommended The answer is. th'
smallest number consistent with the piInci
pies Just explained. To multiply them un
necessarily, Is both useless expense, ant
bad ,asIe. have seen in Massachusetts
small one story house brislling with six llc li
nlng rods, where one, obviously, would hay'
afforded ample protection. Tbls Is like pu,
Ting on half dozen great coats for fear o
catching cold. In my Judgment, most o
the dwellings, require additional projection
To represent, as Ia sometimes done the singl
conductor, IN the supple form proposed b.
DR.. Franklin, as of no use, or even as dan
gerous, appears to me equally inconslsicn
with truth md expedIency for by leadln;
the public To abandon this simple aud chca
torn, while they refrain from purchasin!
such as are more complicated on account q
their expense, we leave The community NOR
unprotected than ever.
II
! In adapting a conductor TO a building, W,
must make the passage 10 the ground a
shor, as Is convenient, aud any bends or turn
that occur, gradual, avoldng all sharp angles
The stays by which the rod is fastened ma
be Of wood, glass, or any other non conduc,
ng substance, or even Of plates Of metal
Staples penetrating the house are not advlsa
| bile. since II The rod should be defective, til
! iightning might be directed laierully at ihcs
! points although II the rods were well con
ncc,cd with the ground, there would be u
/ danger of this.