it was wrecked by the lightning. He says that the sexton told him that
three minutes before the flash he had been tolling the curfew bell, and,
“while in the belfry, he noticed a kind of light on the clapper of the
bell, and heard also, as it were, a sort of hissing noise.”
[This seems to prove two things—(1) The fallacy of the old notion that
ringing the church bells sent away thunderstorms (see also ante, p.
(37);) and (2) that even very imperfect conductors, such as this
conductorless steeple, carry off much electricity by the silent or brush
discharge.—G. J. S.]
Mr. Highton found that the leaden flashings were frequently burst up,
the lead being sometimes forced up somewhat like a miniature volcano.
This he attributes to the explosion of confined atmospheric air, but
obviously water converted into superheated steam would yield a greater
expansive force.
The author quotes a case at Water Newton, Wansford, Northamptonshire,
where, although the Church had tower and spire, and the whole roof was
covered with lead, a tree 90 feet from the spire, and not one-third the
height of the spire, was struck, but the Church was not. This the author
attributes partly to the action of the leaves of the trees, and partly
to there being no iron or other vertical spouting to the Church.
Mr. Highton’s “Practical Rules” are _literatim et verbatim_:—
1st. Where a building has any quantity of vertical metallic work, it
is quite necessary, for its protection against Lightning, that it
should have an artificial Lightning Conductor, (unless the materials
of themselves form a natural one).
2ndly. It is very desirable, that all metallic circuits, especially
those in a vertical direction, should be metallically connected with
the system of Lightning Conductors.
3rdly. That, in many instances, a single insulated Lightning
Conductor attached to a building may become positively injurious and
dangerous; as it may cause many a cloud to discharge its electric
force at that point, which would otherwise have passed over, and
poured its power in some other channel.
4thly. That, where Lightning Conductors are employed, they ought to
be thoroughly well erected, and every course or channel that the
Electric fluid has open to it carefully considered, and a division
of the charge in those quarters provided against.
5thly. That a Lightning Conductor, or a system of Lightning
Conductors, where properly and scientifically erected, are perfect
safeguards against the effects of heavy discharges of Atmospheric
Electricity. But, if improperly applied, they may become a most
dangerous addition to a building.
6thly. That it is essentially necessary for the safety of the
public, that all public buildings, and especially churches, should,
if naturally deficient in safe and secure Lightning Conduction, have
artificial Lightning Conductors erected for their protection.
The above are given as a few general rules. It is difficult,
however, and almost impossible, to lay down any fixed and definite
rules for the erection of Lightning Conductors, to be applicable to
_every_ building; as the very form, shape, and position of the
building, and the _relative position_ of buildings in the immediate
neighbourhood, so materially affect the data for the formation of
those rules. In all cases, therefore, I consider it much better and
safer for an Architect to call in a person of knowledge and
experience in this branch of science, for directions for the proper
erection of Lightning Conductors, than to trust to any printed rules
whatever on the subject.
That, as it is better in cases of illness where life is in danger to
call in a medical man than to apply oneself the remedies set forth
in works on medicine, so is it better, in the protection of
buildings from the disastrous effects of Lightning, to trust only to
the opinions and directions of those who have given to this
difficult branch of science their study and attention.
THUNDERSTORMS.
BY PROFESSOR TAIT, F.R.S.
[Delivered in the City Hall, Glasgow. Nature Aug. 12th, 19th, Sept. 2nd,
9th, 1880.]
(_Abstracted by W. H. Preece, Esq., C.E., F.R.S._)
While a few years ago no qualified physicist would have ventured an
opinion as to the nature of electricity, now, thanks to Clerk-Maxwell,
electric and magnetic phenomena are regarded as mere stresses and
motions of the ether, and are brought within the resources of
mathematical analysis.
Thunderstorms are accompanied by darkness, the result of the intense
shadow of peculiar thick clouds charged with electricity, whose height
varies from 30 yards to 3 miles. The air is never free from electricity.
Snow, sleet, hail, and “luminous rain” are frequently indications of
great electrification. The atmospheric electric charge is usually
positive, and is probably the result of evaporation, but clouds
themselves are more generally negative.
Lightning, as a source of light, is very brilliant, comparable even with
the sun, but its duration is extremely short, hence its intensity is
about equal to that of full moon. The motion of a flash cannot be
detected; hence when people say they saw a flash going upwards or
downwards, they must be mistaken. It is an optical illusion. The
peculiar zigzag form, occasionally bifurcated, is that of a very large
electric spark, varied by local electrification and heat.
The motion of electricity is due to a difference of potential or
electrical pressure. The power of a machine is measured by the utmost
potential it can give to a conductor, and the _time_ required to charge
the conductor depends on its _capacity_. The damage which can be done by
a discharge is proportional to the square of the charge, and inversely
to the capacity of the receiver. Doubling a charge gives fourfold a
shock.
Electricity is entirely distributed on the surface of conductors. The
quantity per square inch of surface is _the density_, and the density
varies with the form of the conductor. On a very elongated body,
terminating in a point, the density becomes so exceedingly great that
the outward pressure of the electricity tending to escape forces a
passage through the surrounding air. Proper lightning rods must be
surrounded with a number of sharp points, lest one should be injured.
The proper function of a lightning rod is not to parry a dangerous flash
of lightning: it ought rather, by silent but continuous draining to
prevent any serious accumulation of electricity in a cloud near it.
Hence it must be thoroughly connected with the earth. At
Pietermaritzburgh, which is well covered with lightning conductors,
thunderstorms are frequent, but they cease to give lightning flashes
whenever they reach the town, and they begin to do so as soon as they
have passed over it.
The violent disruptive effects produced by lightning are principally due
to the sudden vaporization of moisture. Heated air conducts better than
cold air. Hence the killing of flocks and herds.
There is little or no danger inside a thunder-cloud. Thunder-bolts (so
called) are due to the vitrification of sand through which a discharge
has passed. The smell that accompanies lightning is due to ozone.
Sheet lightning and summer lightning are due to the lighting up of the
clouds by flashes of forked lightning not directly visible to the
spectator, sometimes even beneath the horizon.
Thunder corresponds to the snap of the electric spark, intensified and
re-echoed from clouds and surfaces. A longer zigzag flash acts
successively and intermittently from portions farther and farther from
the listener. Hence the crash, clap, rolling and pealing of thunder. The
extreme distance that it is heard is about ten miles, although guns have
been heard fifty miles.
Fireball or globe lightning undoubtedly exists and is probably due to a
species of natural Leyden jar, very highly charged, which no lightning
rod can destroy, except, perhaps, a close net work of stout copper
wires.
Water is the chief agent in thunderstorms. Copious rain and hail always
accompany them. Hot moist air precipitating its moisture as clouds as it
ascends, cooling by expansion but warmed by the latent heat of the
condensed vapour is the main spring. The condensation of aqueous vapour
is accompanied by an enormous development of energy. A fall of one-tenth
of an inch of rain over the whole of Britain gives heat equivalent to
the work of a million millions of horses for half an hour. The mere
contact of particles of aqueous vapour with those of air produces a
separation of the two electricities. Aqueous vapour condenses into cloud
particles, and the agglomeration of cloud particles into rain drops
would enormously increase the original potential of the electrified
vapour.
The column of smoke and vapour discharged by an active volcano gives out
flashes of lightning. Cloud caps on mountains frequently do the same.
Ascending currents of air mean change of density, difference of
pressure, heat condensation, and all the conditions required to produce
a thunderstorm, with its effects forming “one of the most exquisite of
the magnificent spectacles which nature from time to time so lavishly
provides.”
ON THE PROTECTION OF BUILDINGS FROM LIGHTNING.
BY CAPTAIN J. P. BUCKNILL, R.E.
(_Abstracted by W. H. Preece, C.E., F.R.S._)
In the first part of his paper the author popularly explains his own
views of electricity, the causes of thunderstorms, and the purpose
served by a lightning conductor. He urges the theory that lightning is
mostly to be feared by those who live on well conducting areas; and that
non-conducting areas, such as chalk hills, suffer the least, because
their inductive influence on charged clouds is less than in the former
case, even though they be on low ground. Points act as leaks, warding
off lightning by neutralising harmlessly the opposite electricities. The
trees of a forest act as a mass of points, silently discharging thunder
clouds. The potential of a thunder cloud is often a million and a-half
volts. The function of a lightning conductor is “(first) to attract the
lightning to another spot if possible, and (second) to arrange that even
if the building be struck, the work shall be given out at other portions
of the path of the stroke.”
He advocates strange views as to the space protected by a lightning
conductor, which, if true, would tend to show that there is no safety in
lightning conductors at all, for according to him, the safe area rule
may be upset in practice by all sorts of accidental circumstances. He
has, however, not grasped the meaning of the rule. He advocates the use
of iron as the best metal to use, specifying a weight of 2 lbs. per
foot. He thinks wire ropes are more easily applied than rods, ribbons,
or tubes, and prefers a rope 1·2 in. diam. of six strands of seven No.
11 B.W.G. wire, each round a hemp core—costing about 5d. per foot.
Conductors should be specified in terms of electrical units, viz.: ·3
ohms per 1000 yards, and be continuous. Every unavoidable joint should
be soldered. He has found in practice many bad joints, especially in
copper conductors. At Tipner one gave 10,000 ohms, and one in the Isle
of Wight 700 ohms. Each joint was apparently quite sound. He considers
that lofty conductors require no additional conductivity per unit of
length, and that high lightning rods are only required in exceptional
situations.
Several points are preferable to a single point, because the “gathering
power” is increased thereby, and the chance of lightning striking other
things in the immediate vicinity of the conductor is proportionately
diminished; the top of the rod is less likely to be fused when struck,
the stroke being divided between the various points; and also because
the brush discharge is thereby facilitated. He dwells with much emphasis
on the importance of the earth connection, which he regards as a joint,
and advocates greater surface than is usual at present. He illustrates
an excellent deep earth connection formed by a galvanised cast-iron
pipe, 10 feet long and 1 foot in diameter, sunk in a well below the
water level in the dryest season. He insists that both deep and shallow
surface earths are required.
Lastly he insists on periodical inspection, and the careful application
of electrical tests. In an appendix he describes his own testing
arrangements, with the results of nearly 500 tests made by him for the
War Department, from which he concludes “that _with the lightning
conductors erected as they are at present by the War Department_,
electrical testing is of small value.” Nevertheless, in spite of this
strong condemnation he asserts that the conductors now existing on our
magazines and fortifications have never yet failed.
SPECIFICATION (No. 3925. September, 1880) of SAMUEL VYLE. LIGHTNING
CONDUCTORS.
(_Abstracted by G. J. Symons, F.R.S._)
The invention may be divided into two parts. In the first place, the
inventor proposes that in lieu, for instance, of the central strand of a
seven-strand copper wire rope, there shall be a central wire insulated
from the others, and only connected to them at the junction with the
upper terminal, while at the bottom this insulated wire is led up from
the earth to some place where it is easy of access.
Secondly, there is a differential galvanometer, resistance coil, and
other apparatus, which being connected with the conductor and with the
insulated wire, will enable the efficacy of the conductor to be read off
at any time.
ON THE PARTIAL PROTECTION OF BUILDINGS.
(_By Prof. T. Hayter Lewis, F.S.A._)
The following are suggestions whereby the ordinary materials used in
building may, to some extent, be utilised as protectors against
lightning:—
(1) When the roofs and sides of a building are covered with galvanized
sheet iron on a framework of wood, if these coverings have good earth
contacts, either by themselves or through the ordinary iron rain-water
pipe, the building may be considered safe.
(2) Cottages and small houses have usually iron eaves gutters, slate or
tile hips and ridges, cement flashings, and iron rain-water pipes. If
the joints be sound, and the earth at the foot of the rain-water pipes
be moist, the houses will, to a considerable extent, be protected from
the level of the eaves gutters downwards. But as they will be quite
unprotected about that level, a wire rope or metal tape from the top of
the highest chimney to the gutters, which will very much diminish the
risk, is desirable.
(3) In larger buildings the gutters, rain-water pipes, hips, ridges, and
flashings of the roof are often made of lead. If the pipes have good
earth contacts, and conductors be fixed from the chimneys or other
projections to the lead-work, the buildings will be to some extent
protected.
(4) When the hips and ridges of roofs are of slate, terra cotta, or
other non-conducting materials, conductors along the ridges, connected
with the rain-water pipes, and with points along the ridge, and to the
chimneys, will be required.
* * * * *
But all the buildings above described would be exposed to the risk of
imperfect joints, bad workmanship, &c.; so that no structure can be
considered as secure unless it be protected by one or more conductors of
approved size and metal, and with carefully constructed connections and
earth contacts.
INDEX
TO
THE APPENDICES.
NOTE.—It must be distinctly understood that no responsibility for the
statements or views indicated by this index or set forth in the
appendices is assumed either by the delegates collectively or by the
Editor.
Abel, Prof., on Mr. Preece’s Paper, 102
Academy of Sciences, Report made to, 51 _et seq._
Accident at Athelney, Bournemouth, 201
„ at Carmarthen, 217
„ at Caterham, 210
„ Masulipatam, 206
„ Trolley Bottom, Herts, 196
„ in Belgium, 129
„ in England, 38, 129
„ in low-lying parts of France, 129
„ in mountainous parts of France, 129
„ to a French frigate, 200
„ various, 126
„ within small areas, 201
Action, Mechanical, of lightning, 85
Adams, Prof. W. G., Abstracts by, 76, 82
Addiscombe, chimney of house struck, 38
“Ætna,” Ship, struck at Corfu, 88
Aigrettes or brushes of points, 139
(_See_ POINTS MULTIPLE).
Air in electric field in state of strain, 135
„ terminals (_See_ POINTS).
Alatri, Cathedral of, 126
Allen, R., Letter from, 183
All Saints’ Church, Nottingham, struck, 37
Alphand, M., his Report, 67
Alphington Church, near Exeter, struck, 37
America, gutters and water pipes used, 125
Analysis of Manufacturers’ Remarks, &c., 17
Anderson, R., on Lightning Conductors, 120
„ on testing, 111, 127
Androuët, M., his assistance, 225
Angle iron conductors, advantages of, 111
Angles, Sharp, to be avoided, 11, 16, 28, 71, 94, 99, 178
„ useful for discharging electricity, 111
Arago, on bends in conductors, 94
„ „ earth terminals, 95
Architects, Royal Institute of British, Report of, 27
Area protected (_See_ PROTECTION, AREA OF).
„ Sectional, 15, 18, 22, 49, 110, 131, 132, 195, 223
„ „ insufficiency of, 63
„ „ varied with length, 7, 9, 12, 13, 14, 19, 20, 24, 131
„ „ not varied with length, 4, 16, 243
Asted, Col., Report of Accident, 206
Atmospheric Electricity, 112, 119
„ „ by D. Brooks, 117
„ „ by R. Phillips, 98
„ „ origin of, 117
Attachment should always be of same metal as conductor, 21
„ to building, 7, 8, 9, 11, 13, 14, 16, 21, 24, 31, 39, 81, 99, 103,
115, 125, 130, 193
Attraction, Conductors do not attract lightning, 71
„ Specific, equal in all bodies, 73
Attractive points, 127
Austria, Accidents in, from Lightning, 126
Aylmer, J., his assistance, 228
Ayrton, Prof., Abstracts by, 43, 83, 85, 90
„ „ on Clerk Maxwell’s Lightning Conductors, 132
„ „ on Indian telegraphs, 102
Babinet, M., his Report, 60, 66
Backstroke of lightning dangerous, 85
Baker, A. J., his Report, 34
Ball, Hollow, with small points (_See_ POINTS MULTIPLE) 13, 23
„ is a point when compared to a cloud, 73
„ lightning, (_See_ LIGHTNING BALL.)
Ballu, M., his Report, 67
Band (_See_ TAPE and PLAIT).
Barns full of new hay likely to be struck, 125
Barque “Southern Queen” struck, 205
Bar of iron, bad joints in, 116
„ Melted by lightning, 61
„ Rectangular flat, 74
„ Small, become heated, 116
Base of conductor should bifurcate, 65, 243
Batteries, Casemated, 70
Bayonne, Powder magazine at, 87
“Beagle,” H.M.S., struck by lightning, 195
Beams, how connected, 10
Becquerel, M., his Report, 60, 66
„ on discharge of lightning, 131
„ on conducting power of metals, 124
Belgrand, M., his Report, 67
Bell, Hornsby & Co.’s experience, 193
Bells in church steeple, 85
Bell wire acts as a conductor, 39, 195
Bends, Sharp, to be avoided (_See_ ANGLES).
Berehaven lighthouse struck by lightning, 208
Bisby, Mr., of Leeds, his conductor, 75
Bishop’s Rock Lighthouse, 190
Blitzableiter, Von G. Karsten, 114
Blunt conductor (_See_ BALL _and_ POINTS).
Boat, Packet, struck (_See_ SHIPS) 61
Bolts, Iron, attracted lightning, 40
„ to be connected with conductor, 11
Books on Lightning Conductors, Catalogue of, 143
Bootham Bar, York, 219
Borrel, M., his views, 226
Boy on pony, pony killed, boy escaped, 48
Branches, Connecting, 183
Brandon, D., his Report, 34
Brass not a reliable metal, 62, 124, 227
„ wire rope used in Bavaria, 124
Break in conductor not fatal, 53
„ „ „ to be avoided, 63
Brescia powder magazine blown up, 76
British Association Report, 1860, 46
Brixton Church struck, 84
Broek, R. Van der, Abstracts by, 114, 119, 137, 138, 140, 141
Brook, Conductor to be carried to it, 14
Brooks, D. 103, 181
Brough, Mr., on Lightning Rods, 19, 49, 181
Bruntcliffe, Yorkshire, Gunpowder store destroyed, 74, 216
Brussels, Town Hall at, Lightning protector at, 138
Brydone, Mr., Report of an accident, 85
Buchanan, G., on gas works chimney, 89
Bucknill, Capt., on the protection of buildings, 243
Building, containing masses of metal, 61
„ continually under attacks, 123
„ injured, though protected, 27, 128
„ Long, to have several conductors, 25, 202
„ Metallic, safe, 72
„ protected by cage of wires, 132
„ struck from, 1589 to, 1879, 126
Burges, Mr., 190
Cable conductors (_See_ ROPE).
Cagniard de Latour, M., his Report on Points, 60, 66
Calcutta, Report on conductors at, 117
Callaud, A., his Treatise, 103
„ his grapnel in basket of coke, 131
Canton, Mr., his experiments in London, 80
Capacity of conductors, 127
Caps, Cast-iron, to chimneys, 103
Carbon in well, 180
Carmarthen, Accident at, 217
Casing of lead or wood for iron earth terminals, 125
Catalogue of works upon lightning conductors, 143
Caterham, accident at, 210
Cathedral of Alatri, 126
Cavendish, Hon. H., his Report, 76, 79
Cemented water tank, iron conductor in it, 130
Chain conductors melted, 61, 62
„ though broken, still useful, 54
„ objectionable, 9, 61, 62, 88, 123
„ Early use of, as conductors, 122
„ Old iron, for earth terminals, 74, 204
Chapel, Rycroft, struck, 45, 46
Chapman, Gen. Sir F. E., his Report, 72
Charcoal for earth terminals, 12, 16, 58, 125, 126
Charles, M., his Report on Instructions for erecting conductors, 57
Cheapness of galvanized iron, 132
Chimney, Accidents to, soon after erection, 194
„ Granite, in Plymouth Dockyard, struck, 73
„ Metal Caps to be joined to Conductors, 125
„ New, contain much moisture, 194
„ not struck that had conductors, 193
„ of Edinburgh Gas-works, 89
„ over, 90 feet have conductors, 193
„ rod to be on, 100
„ rope on, liable to corrosion, 125
„ Shafts, copper band round top of, 9
„ Stacks are Conductors, 7
„ struck, 27, 28, 40, 45, 193, 194
„ struck because of heated air, 113
„ struck before completion, 94
„ struck that had no conductors, 38, 193
„ very rarely struck at Glasgow, 193
„ with soot dangerous conductors, 106
„ Zinc, struck, 37
Church, Brixton, struck, 84
„ Charles, at Plymouth, 86
„ Christ, Carmarthen, 217
„ Rosenberg, in Carinthia, destroyed, 1730, 123
„ St. Bride, Fleet Street, damaged, 126
„ Ste. Croix, Ixelles, struck by lightning, 140
„ St. George, Leicester, damage to 126, 240
„ St. Giles, Cripplegate’s truck, 196
„ St. Mary, Genoa, 126
„ Southampton, damage to, 126
„ Steeple at Bodmin, destruction of, 202
„ struck, 29, 37, 106, 126, 137, 199
„ struck near Isleworth, 199
„ tower, with pinnacles, 10, 29, 137
„ towers struck in past, 400 years, 202
„ with lightning conductor, 128
„ without lightning rods damaged, 126
Cinders with grating (_See_ EARTH TERMINALS).
Circuit to be tested by galvanometer, 130, 244
Cistern dangerous for base of conductor, 64
Claire-Deville, M., his Report, 67
Clamps, Iron, acted as conductors, 43
Clark, J. E., Accident at Bootham Bar, York, 219
„ Latimer, Abstracts by, 103, 106
Clay, Conductor to be taken below surface of, 14
Clevedon Church struck, 126
Clifton, E. N., his Report, 41
Clips, Gun-metal, 24
Clouds are not perfect conductors, 101
Cluster of points (_See_ POINTS MULTIPLE).
Coke, broken, better than charcoal, 116
„ prevents action of sulphur, 120
„ round conductors, 9, 116, 118, 126, 131
%center%(_See_ EARTH TERMINALS).
Cole Brothers, 192
Colliery Chimney near Sunderland struck, 193
„ Workings, Lightning in, 237
Colson, J., his Report, 28, 34
Commission on damage by lightning, 127
Comparative resistance to fusion, 141
„ „ rupture, 141
Conducting power depends on amount of copper in conductor, 200
„ „ of metals, 74, 124, 131, 139
„ „ of wires, 177
Conduction, is it a question of surface or of mass? 15, 18, 49, 132
Conductive capacity deficient in trees, 127
Conductor at ends of buildings has radius of protection lessened, 134
„ Construction of, 63, 107, 178, 179
„ Cost of, for Houses of Parliament, £2314, 122
„ damaged by holdfasts, 115, 193
„ destroyed at ground line, 131
„ partly destroyed, yet useful, 62
„ deteriorate, 127
„ dimensions of (_See_ SIZE OF).
„ do not attract lightning, 88
Conductor, every, should be complete in itself, 22
„ Examination of, 9, 72, 102, 111, 124, 127, 130, 131, 132, 179, 244
„ Expansion of, 11, 70, 125, 128, 226
„ First, 121
„ „ in England, 85, 121
„ „ in Europe, 122, 129
„ for lighthouses, 195, 199
„ for iron ships, 122, 200
„ for wooden ships, Snow Harris’s, 195, 199
„ for steeples, with horizontal bands, 125
„ how to be connected with metal portions of buildings, 65, 125,
126, 128
„ imperfect, Effect of, 21, 209
„ in contact with metal in chimney, 111
„ influenced by new water and gas mains, 127
„ influenced by trees, 127
„ is it to be a rope, rod, tube, or band?, 18, 132, 195
„ joints in (_See_ JOINTS).
„ laid in underground water, 128
„ led into cemented water tank, 130
„ „ water butt, 107
„ Main, 183
„ must protect ridge, gable ends, and eaves, 112
„ not to be insulated (_See_ INSULATION).
„ not to rise less than, 15ft. above chimney, 122
„ now same as Franklin’s, 124
„ number necessary, how determined, 51
„ of copper, 107, 130
„ „ and zinc wire, 205
„ „ tape, 206
„ „ rope, 196, 203
„ „ the best, 125
„ of hollow tube, 122, 196
„ of Hotel de Ville, Brussels, 126
„ of iron, 55, 107, 125, 131, 139, 140
„ of large surface better than rod, 113
„ of links of copper, 202
„ of numerous thin wires, 139
„ of solid bolt, 196
„ of zinc wire melted, 107
Conductor on buildings, to be linked together, 204
„ on churches at Torquay defective, 130
„ on ridge of roof, 125
„ outside, 60, 126
„ Points of (_See_ POINTS.)
„ properly made, and properly fixed, insures safety, 12
„ protects conical space (_See_ PROTECTION, AREA OF).
„ reached water without earth plate, 128
„ Ridge, 68, 177
„ should extend above building, 106, 202
„ should it present a large surface section? (_See_ AREA SECTIONAL).
„ size of, 10, 12, 18, 19, 22, 86, 119, 125, 126, 129, 131, 192,
194, 202, 214, 223, 225, 243
„ spirally coiled up, 128
„ struck by lightning, 128
„ supposed perfect, proved defective, 131
„ theory and action of, 106
„ to be close to wall of building, 11, 15, 86
„ to be continuous, 179
„ to be fixed by iron staples, 125
„ to be, 4 inches from walls and roofs, 118
„ to be inside, 126, 225
„ to be on side most exposed to weather, 60
„ to be of metal of high conductivity, 131
„ to be symmetrically arranged, 105
„ to earth by shortest route, 126
„ to gas and water mains (_See_ EARTH TERMINALS).
„ to Middlesboro’ Hospital, 204
„ to rest in hooks, 179
„ to St. Alphege Church, Greenwich, 206
„ to St. Michael’s Church, Blackheath, 205
Cone of platinum (_See_ PLATINUM).
Conic Terminals (_See_ POINTS).
Conference Circulars by the Lightning Rod, 3, 175
Conic Space, protected (_See_ PROTECTION, AREA OF).
Connection (_See_ EARTH TERMINALS, _and also_ JOINTS).
„ of metallic masses, 9, 10, 76, 77, 186
„ „ not necessary, 126
Contact between iron and copper to be avoided, 111
Continuity between point and earth contact, 129
Contraction to be provided for, 70, 125, 128
Copper and iron form best conductors, 119
„ and iron soldered, 107
„ and zinc wire bad for conductors, 205
„ Australian, 124
„ better than silver, 139
„ conducting power of, 19, 124, 131, 139
„ conductors, 18, 70, 86, 117, 119, 125, 126, 130
„ conductor too small, 126
„ earth plate in dry sand, 128
„ is it alone to be used?, 18
„ less liable to oxidise, 131
„ not to be in contact with galvanized iron, 102
„ nuts, 192
„ or iron conductors, 70, 192
„ plates, bent, 125
„ plate ending for conductors, 128
„ plates to provide for expansion, 125
„ points (_See_ POINTS).
„ preferred to iron, 131
„ purity of, 19, 124
„ rarely used, 125
„ tape recommended, 206
„ rod conductor, 185, 186, 202
„ rod, ½ in. diam. has never been fused, 125
„ rod on Eddystone Lighthouse, 184
„ rope conductor carelessly fixed, 196
„ rope conductor insulated, 194
„ rope to be used, 125,131
„ „ of thick wires
„ Russian, 124
„ Spanish, 124
„ tubing, 74, 122
„ wire fused throughout its length, 195
„ wires, deterioration of, 114
„ wire rope applied to St. Paul’s Cathedral, 131
„ wire rope, dimensions of, 8, 223
Corn stacks fired by lightning, 187
Coronal to be placed on chimneys, 132
Corrosion of joints of rod, 126
Cotton Mill, Explosion at, 239
Coulomb, M., his Report, 51, 53
Couplings, form of (_See_ JOINTS).
Coutt’s Brewery, a rod at, 89
Cramps, iron, stones held by, 29
Cross, Metal, 53, 85, 227
Croxton Park, trees struck, 48
Cruickshank, A., his Report, 44
Crutches on roof to carry rod, 52, 227
Current, what it is, 100
Cutting and Co., their conductor coupling, 216
Cylinder in water (_See_ EARTH TERMINALS).
Cylindrical rod or wire rope the best, 134
D’Alibard, M., his experiments at Marly, 80
Damage to building by alteration of position of safe, 127
D’Amico, Sig., 179
Damp air, a conductor, 48
Dampness of new chimneys cause of being struck, 194
Danger of explosion from use of gas pipes, 201
Davioud, M., his report, 67
Davis, H. D., suggestion about gas pipes, 201
„ Jno. & Son, their answer, 14, 15, 17
Davy on conducting power of metals, 124
Deaths from lightning, 100, 126
De la Place, M., his Report to French Academy, 51
De la Rive says blunt points or balls equally effective, 106
De la Rue’s (Dr. Warren) experiments, 133, 135
Delaval, M., his Report, 76
Delieul, Messrs., points made by, 66
De Lor, M., his experiments in Paris, 80
Denmark, lightning conductors in, 176
Desains, M., his Report, 67
De Saussure’s neighbours frightened at his conductors, 122
De Senarmont, M., his Report on points, 66
Designs for protecting private houses, 125
Despretz, M., his Report on points, 66
Destruction of conductors by use of iron wall eyes, 131
Dimensions of conductors (_See_ CONDUCTORS, SIZES OF).
Dimensions of upper terminals, 17, 18
Discharge diverted from conductor by an anchor, 128
„ from thunder cloud over plane surface would be vertical, 127
„ of electricity by trees lessens energy of lightning, 127
„ of electricity of high potential obeys laws of Ohm, 134
„ of lightning—Earth contact, 131
„ passes through conductor, Faraday, 132
Discharging fork to be attached to lower end of conductor, 11, 231
Doherty, J., on explosion at Swan Cotton Mill, 239
Doors, copper, to magazines, 74
„ iron, to powder store, 76
„ lightning passed out of, 27, 48
Drain, conductor to be led into, 14
Duc, M., his Report, 67
Dugmore, Mr., his evidence, 198
Duhamel, M., his Report, 60, 66
Dulong, M., his joint instructions, 59
Dum Dum, accident at, 181
Du Moncel, Comte, 67, 226
Dungeness Lighthouse, 183, 186
Duprez, M., his statistics of buildings and ships struck, 91
„ on height of points, 96
Dymond, E. E., Abstracts by, 51, 108
Earth, “bad”, 110, 117, 126, 127, 209, 210, 218
„ moist, better than a well for end of conductor, 74
„ plate, pipe, or tube, 9, 24, 100, 114, 115, 118, 120, 128, 177,
179, 186, 231
„ plates at Torquay carried out to sea, 130
„ „ unnecessary, 16
„ Terminals, 11, 13, 14, 15, 21, 56, 95, 102, 106, 109, 116, 126,
131, 140, 180
„ „ at base of rain water pipe, 132
„ „ bad, 110, 117, 126, 127, 209, 210, 218
„ „ Borrell’s, 226
„ „ Callaud’s, 104, 125, 131
„ „ destroyed in moist earth, 116
„ „ Discussion on, 131
„ „ Duplicate, 65
„ „ important, 11, 71, 126, 131, 243
Earth Terminals of conductors in iron box, 126, 231
„ „ of conductors, Stotherd, Lt.-Col., 130
„ „ in wells, 15, 56, 60, 74, 77, 100, 118, 126, 139, 179, 180,
231, 243
„ „ iron should be galvanised, 120
„ „ length of, 11
„ „ multiple, 139, 243
„ „ Oxidation of, 125, 131
„ „ Rules for, 64, 72, 132
„ „ to be accessible, 68
„ „ to be carried away from building, 107
„ „ to be connected, 120
„ „ to be deep and wet, 107
„ „ to be good, 126, 130
„ „ to be in moist ground, 21, 52, 55, 56, 58, 74, 113, 118, 123,
124, 125, 126, 131
„ „ to be tested, 111, 131
„ „ with charcoal cinders or coke, 9, 12, 16, 23, 24, 58, 104, 116,
120, 125, 126, 131
„ „ with coil of conductor, 9
„ „ with galena, &c., 58
„ „ with gas pipes (_See_ GAS).
„ „ with iron forks or harrows, 11, 131
„ „ with old iron, 74, 204
„ „ with water, 52, 53, 67, 68, 126, 130, 140
„ „ „ pipes, 9, 26, 46, 55, 56, 68, 118, 125, 126, 127, 128, 132,
231, 235, 243
Eddystone Lighthouse, 183, 184, 186, 189, 191
Effects of climate on copper and zinc wire ropes, 205
Electric current checked, 193
„ discharge takes path with best conduction, 127
„ fire not diverted from its path by rod, 125
Electricity a terribly explosive power, 72
„ Atmospheric, 98, 112, 117, 119
Electricity, frictional and atmospheric the same, 82, 112
„ carried off by water pipe, 126
„ for telegraphic purposes follows Ohm’s laws, 133
„ is force, not matter, 100
„ of earth negative—atmosphere positive, 112
„ Static, laws of, 132
„ will leave small conductors for large ones, 204
Electrodes, 110
Elevated rods preferable to low conductors, 79
End of conductor, lower, to be coiled up, 9
Energy of lightning lessened by trees, 127
England, accidents from lightning, 126
Escurial, no conductor on, 100
Examination of Conductors (_See_ CONDUCTORS, EXAMINATION OF).
Expansion of conductor to be allowed for, 11, 70, 125, 128, 226, 229
Experiment on wire across Thames, 121
„ on plait of copper and zinc wire at Blackheath, 205
„ with a very thin strip of tinfoil, 199
„ with glass rods, 121
Explosion of a gas meter, 239
Explosions, electrical, their cause, 81
Extent of surface does not favour lightning discharges, 134
Eyes for fastening conductors, 99, 115 (_See_ ATTACHMENT).
Faraday on conductors, 83, 84, 89, 102, 132, 183, 186, 187, 189, 190,
195, 196, 199.
Field, Rogers, C.E., on accident at Caterham, 210
„ on ventilating pipes, 216
Fire of inflammable materials, 127
First conductor erected in England, 85, 121
First conductor fixed in Europe at Hamburg, 122, 129
Fixing conductors to ships, 87
Fizeau, M., his report on powder magazines, 66, 67
Flagstaff should have a conductor, 70
„ struck, 44, 187, 196
Flashing, Lead, how to connect wire rope with, 10, 11, 34
Flash, lightning, effects of, 84
Flow of electricity through conductors, 133
Flues copper, 183, 185
„ lightning passed down, 38, 39
„ warm, and an iron grate, a dangerous conductor, 101
Forest Hill, chimney of house struck, 38
Forms of upper terminals (_See_ POINT).
Formula for determining area protected (_See_ PROTECTION, AREA OF).
Foster, Prof. G. Carey, on Personal safety, 233
Fountains, Public, conductor lead away from, 56
Franklin, Dr., and wet rat, 85
„ discovered pointed metal best conductor, 121
„ erected lightning rod to his house, 121
„ experiments, 79, 84
„ „ repeated by Buffon & Dalibar, 115
„ first conductor was melted, 116
„ his report to French Academy, 51
„ on cold fusion, 102
„ on connection of lightning rod, 54
„ report on Purfleet, 76, 126
„ round rod best, 114
„ success in pushing use of conductors, 121
„ tried his kite successfully, 121
Freeman & Collier, their answer, 10, 17
French instructions, 51
„ „ on area protected, 22
Fresnel, M., his instructions, 59
Frost, A. J., Abstracts by, 99, 118
Fusion, metals which resist, only to be used, 139
„ of defective conductor, 215
„ of rod, Wheatstone on, 83
Gable near conductor struck by lightning, 28
Galena, and melted sulphur, Bed of for end of conductor, 58
Galvanic action between iron and copper, 111, 130
„ of wet and smoke on conductors, 205
Galvanised conductor painted, 139
„ iron, 19, 67, 68, 72, 101, 120, 124, 125, 132, 139
„ not to be in contact with copper, 102
Galvanised iron best material for earth contact, 130
Galvanometer for testing earth currents, 131
Gas and water mains, 113
„ „ „ utilisation of, 9, 28, 37, 39, 44, 72, 100, 102, 103, 108,
114, 117, 125, 126, 128, 138, 201, 231, 235
Gas coke for earth terminal, 23, 24
Gases from chimney injure conductors, 111
Gas ignited, 219
„ meter exploded, 239
Gasometer struck, 43
Gas-pipes, Soft metal, not to be used as conductors, 108
Gavarret’s, M., experiments, 139
Gavey, J., on accident at Carmarthen, 217
Gay Lussac’s iron conductor recommended, 104
German “reception rod” of iron, 125
Geneva cathedral, 103
Genoa, St. Mary’s Church, 126
Gilbert, Dr. (1600) magnetic and galvanic action one force, 120
Gilt point (_See_ POINT GILDED.)
Girard, M., his instructions, 59
Girders, how connected, 10
Glass, foundation of house insulated, 118
„ insulators (_See_ INSULATORS.)
„ repeller, 83, 185, 186
Globular Lightning (_See_ LIGHTNING, BALL).
Goldie’s, Mr., experience, 193
Governments, French and English, size of rod sanctioned by, 12
Grapnels and gratings for earth plates, 125, 126, 131
Gray, J. W. and Son, their answer, 7–9, 17
“Gridiron,” Termini of ribs pointed, 23, 24
Groome’s, J. E., evidence, 196, 197, 198
Ground connection (_See_ EARTH TERMINALS).
„ containing ironstone, 48
Guillemin’s, M., opinion, 132
Gunpowder stores, conductor, how to be fixed, 82
Gutters, Metallic, 40, 41, 45, 46, 47, 60, 125, 213
„ must be connected with conductor, 60
„ utilization of, 47, 125, 244
Guyton, M., his practice with charcoal, 58
Haigh & Son’s Colliery, 74, 216
Harris, Sir William Snow, Crown adviser, 8
„ combated the idea that rods attracted lightning, 122
„ conductors to ships and buildings, 83, 122, 130, 196
„ in conflict with Faraday, 195, 196, 200
„ on Sectional Area, 110
„ on copper conductors, 202
„ on expense of conductors, 49
„ on fusion, 86
„ on hollow or solid conductors, 74
„ on relative conductivity of metals, 71
„ on shipwrecks by lightning, 90
„ on thunderstorms, 85
„ Principles adopted by, 70, 101
„ regarding insulators, 15
„ report on safety of conductors, 72, 110
„ says discharges pass over surface, 132
„ suggestions issued in army circulars, 122
Hauksbee, F., F.R.S., similarity of electric flash and lightning, 121
Hawksley, T., his report, 37
Hay a bad conductor, 127
Hay newly gathered, inflammable, 127
Heated smoke from chimney, a conductor, 132
Heckingham poorhouse struck, 87
Height of rods, 120, 124, 125, 139, 177
Hemispheres of brass, experiments with, 105
Henly, W., his report, 78, 79
Henry, Prof. Joseph, on construction of lightning rods, 99, 181
Herring’s, Mr., evidence, 196
Heryet, Chas. J., his opinion, 206
Higginbotham’s, Mr., evidence, 194
High buildings a source of safety to lower ones near, 12
Highton, E., on lightning conductors, 239
Hill, A., his Report, 37
Hine, G. J., his Report, 37
Hine, T. C., and Sons, Architects, ground plan of Nottingham Castle, 26
Holborn Union Infirmary, Upper Holloway, struck, 39
Holdfast, brass, 16
„ copper, 7, 8, 13, 16, 21, 24, 39
„ driven in too tight, 16, 193 (_See_ ATTACHMENT.)
Hole in ship’s side, made by lightning, 62
Honeyman’s, J., evidence, 194
Hook and rings used as joints, 94
Hoop iron in brickwork of chimneys struck, 46
Hoops round chimney, 89
Hopkins, Rev. G. H., his Report, 30
Horizontal conductor, 71
„ conductors for steeples, 125
Horsley, Bishop, his Report, 79
Hotel des Invalides, Paris, conductor on, 86
Hotel de Ville, Brussels, conductors of, 126
House at Bethnal Green cut in two by lightning, 41
„ at Bournemouth with, 7 conductors, 199
„ at Cannes (France) struck, 198
„ near trees struck, 127
„ of Parliament protected by Harris’s conductors, 122
„ with two separate conductors, 128
Hugueny, M. F., on “Le coup de foudre de l’ile du Rhin”, 99
Ignition depends on retardation of discharge, 127
Infirmary, how to be protected, 10
Ingenhousz’s, Dr., experiments, 122
Ingram, Mr., of Belvoir Castle, on trees struck, 47
Inspection of conductors, 9, 72, 102, 111, 124, 127, 130, 131, 132,
179, 244
Instructions, 63, 99, 176, 181, 240
„ British Army Circular, 70
„ French Official, 59
„ for formation of good earth, 64, 72, 132
Instrument hut at Valencia, how protected, 105
Insulation, shock decreased by, 118
Insulators, 34, 37, 76, 99, 184, 186, 194
„ approved, 13, 118
„ objected to, 8, 11, 13, 14, 16, 21, 24, 68, 69, 73, 86, 89, 103,
111, 118, 126, 139, 186, 226
Iron a better conductor than formerly, 19
„ and copper form best conductors, 119
„ as a conductor, not objected to if galvanised, 19
„ bar, 131, 226
„ „ melted, 61
„ bars on ridge for metallic connection, 125
„ better than copper, 192, 243
„ box for earth contact of conductors, 126
Iron buildings covered with asphalte, 70
„ built ship, metal-rigged, if protected, 122, 200
„ cables, galvanized, sometimes used, 125
„ conductors, 18, 69, 74, 116, 125
„ „ bad, 9, 39, 192
„ „ good, 81, 243
„ „ cost of, 19, 70, 124, 132
„ „ should weigh, 13 to, 37 oz. per foot, 119
„ galvanized for conductor, 74, 116, 132, 139
„ has greater specific heat than copper, 132
„ its high temperature at fusion, 132
„ in coke undergoes no change, 116
„ Joints in defective, 116
„ not to be used for rods, 123
„ points, 88, 138
„ pumps reaching to water act as attractive points, 127
„ rain water pipes, good conductors, 102, 113
„ “reception rod” used in Germany, 125
„ rods on all sides best protection, 124
„ safe in altered position caused damage to building, 127
„ staples and wall eyes, 125, 130
„ terminal rods, 124, 125
„ underground, destruction of prevented, 125
„ wires surrounding copper wire, 200
Isolators (_See_ INSULATORS).
Italy, Lightning rods used there, 179
Jarriant, M., his books abstracted, 111, 115
„ his manufactory, 227
Jenkin, Professor, says point prevents discharge, 106
Jerman, J., his report, 37
Johnson, Clapham & Morris, their answer,13
Johnston, W. P., 181
Joints, avoided in wire cables, 132
„ Cutting & Co., 216
„ damaged, 69, 110, 126
„ how avoided in upper terminals, 23
„ how made, 7, 9, 10, 11, 13, 14, 16, 20, 24, 52, 55, 59, 63, 70,
71, 103, 179, 192, 243
„ must be perfect, 58, 131
„ of bars always defective, 116
„ of extra thickness, 74
„ of rain water pipes, 132
Joints should be metallically continuous, 20
„ soldered, 9, 24, 66, 68, 70, 71, 102, 123, 125, 139, 140, 141, 243
„ to be avoided, 10, 11, 16, 20, 63
Journal of Society of Telegraph Engineers, May, 12, 1875, 130
“Jupiter” ship struck, 62, 95
Karsten, Prof. D. G., lightning conductors, by, 119
Kew, experiments at, on atmospheric electricity, 112
Kilbourne, Lieut., 181
Kirchoff, Prof., on connection with gas mains, 235
Kite, Silk, Franklin’s experiments with, 80
Korte’s, Messrs., Paper, 105
Lacoine, M., on area protected, 134
Lane, T., his Report, 79
Lantern on lighthouse, 184, 186
La Place, M., his Reports, 53, 57
Lateral discharge, 73, 83, 84, 85
Latham, Baldwin, on conductors, 202
Law, E. J., his Report, 37
Laws of Static electricity, 132
Lead a bad conductor, 123
„ at joints, 94, 125
„ casing for upper terminals, 131
„ floors, 188, 189
„ liked because of fitting sharp curves, 123
„ pipe for earth connection, 77
„ roofs and spouts, 51, 82, 102
„ thin sheet of, covering ends of wire, very dangerous, 20
Leaves of trees draw off electricity, 84
Lefevre-Gineau, M., his instructions, 59
Le Gentil, M., his observations, 84
Length and sectional areas, proportion between, 14
„ of conductor above top holdfast destroyed, 193
„ of conductor determines amount of resistance, 131
Lenz, M., on conducting power of metals, 124
Leroy, M., his Report, 51, 53
Lewis, Prof. T. Hayter, Abstracts by, 70, 79, 81, 84, 100, 110, 112,
117, 120, 179
„ his joint Report, 28, 37
Leyden discharges and lightning flashes, 84
„ Jar, 121
Lichtenberg of Gottingen, his opinion, 129
Liddell, J., on lightning conductors, 202
Lighthouses and exposed buildings protected did not suffer, 106
Lighthouse at Berehaven struck by lightning, 208
„ damaged by lightning, 196
„ lightning rods on, 183, 190
Lightning an immense electric spark, 123
„ Ball, 99, 101, 102, 108, 205, 242
„ Bifurcated, 45
„ conductor (_See_ CONDUCTOR).
„ diffused, 108
„ does it pass inside or outside conductor?, 15, 18, 49, 132
„ Flash, 108
„ follows line of least resistance, 108
„ Force of, exemplified, 45
„ Globular (_See supra_ BALL).
„ going to earth without conductor, 128
„ identical with electricity, 82
„ incandescent matter, 100
„ in colliery workings, 237
„ leaves conductor and enters chimney, 203
„ passed down mainmast and through ship, 195
„ passed to iron supports, 128
„ passing out of a ship by a copper bolt, 205
„ Personal safety from, 233
„ protectors (_See_ CONDUCTORS).
„ ran along a bell wire, 195
„ „ thatched roof of house, 128
„ Rod Conference, their Circular, 28
„ Rods (_See_ CONDUCTORS).
„ Sheet, 108
„ the cause of, 81
„ various forms of, 108
Lime, to prevent oxidation of cylinder, 140
Line, conductor should run round building, 134
Linked system of conductors introduced by Sir W. S. Harris, 204
Links of chains, 179
Llandaff Cathedral, conductor on, 102
Lofty buildings require larger rods (_See_ AREA, SECTIONAL).
Long conductors above buildings, their effect, 77
Long’s, F., account of injury to Wells Church, 195
Louvre, New Buildings of the, Special Report for, 64
„ slightly injured by lightning, 123
Low straggling buildings should have several conductors, 15
Lucas, Mr., his Report, 67
Lussac, Gay, M., his Report, 57, 59
McDonald’s, Mr., experience, 193
McGregor, W., protection from Lightning, 106
Magazine, copper doors and windows to, 74, 216
„ of metal, the safest, 73
„ underground, 70
„ well at each end of, 126
(_See also_ POWDER MAGAZINES).
Magne, Mr., his Report, 67
Mahon, Lord, his Report, 79
Mairie, of, 20th Arrondissement struck, 69
Majendie, Major V. D., his Report, 74, 216
Malcolm, Major, R. E., discussion on lightning conductors, 131
Mann, Dr. R. J., Lecture at Society of Arts, 108
„ discussion on earth connections, 131
„ discussion on lightning conductors, 131
Man might touch conductor in thunder storm, 126
Marseilles, Powder Magazine at, how to be protected, 51, 52
Massingham, T., evidence and letter, 15, 16, 17, 193
Masses, metallic must be connected with conductor, 60, 94, 104, 126,
132, 240
Mass or surface, which conducts?, 13, 15, 18, 49, 74, 132, 227
Masts of large vessels, each to have a conductor, 6
Masulipatam, accident near, 206
Materials, inflammable, not ignited, 127
Maxwell, Hugh, on kind of trees struck, 47
Maxwell’s, Clerk, Theory, 109, 126, 132, 133
Mechanical action of lightning, 85
Meiszner’s improvement, 130
Melsens says discharge passes over surface, 132
„ System of protection as applied to monument at Lacken, 230
„ various works by, 124, 138, 140, 141
Men-of-war, old conductors in, 202
Merton College, Oxford, damaged, 126
Metallic cap may assist protection of house, 132
„ circuit, 126
„ connection must be perfect, 130
„ connections on ridge by iron bars, 125
„ joints, 89
Metals, contact of dissimilar, results in decay, 19, 21
Metal cowl of chimney struck, 198
„ for points must be good conductor, 139
„ immaterial if sectional area be large, 131
„ in buildings, contiguity with to be avoided, 5
„ inside or out, to be connected with conductor, 125, 126
„ melted, dimensions of, 61, 83, 223, 231
„ of high conductivity for conductors, 131
„ stays and fastenings, 184, 185
Michel, M., Papers by, 67, 68, 111, 131
„ on galvanised wire rope, 131
Milne, D., his Report, 44
Mining Engineers, Enquiry by, 237
Mohn’s, H., Lynildens Farlighed I Norge, 106
Moist earth destroys terminal, 116
„ for lower terminal, essential, 21, 52, 56, 58, 125, 126
%center%(_See_ EARTH TERMINALS).
Moisture, Access of, to surfaces in contact, 71
Moncel, Comte du, his Report, 67
„ „ his opinions, 226
Monte Video, English Consul’s house struck, 195
Montgolfier, M., his Report, 57
Monument, London, its immunity from injury by lightning, 103
Morea, Signor Lerigi, 180
Müller’s, Prof., conditions for lightning conductors, 129
Müller’s, Dr. Hugo, experiments, 135
Municipal buildings in Paris, lightning rods for, 67, 225
Munson, D., & Co., their rods, 216
Murgatroyd, J., his report, 39
Murray, J., on Atmospheric Electricity, 82
Musgrave, Dr., his report, 79
Myers, Gen., 181
Nails, copper, used in attaching conductor to building, 14
%center%(_See also_ ATTACHMENT).
Nairne, E., his report, 79
Nash lights, 183, 187
National Institute (of France) report made to, 53
Nelson column, 90
Newton, Sir I., machine of glass, 120
“New York,” packet boat, struck, 61, 62
Nickson, Mr., his report, 78
Nottingham, Castle, how protected, 23, 24
Nuts, copper, 192
%center%(_See_ JOINTS).
Number of persons killed by _one_ discharge, 129
Objects on plains attract lightning, 127
Odour, sulphurous, of lightning, 85
Official instructions:
„ Denmark, 176
„ England, 70–74
„ France, 51–69
„ India, 181
„ Italy, 179
„ Norway, 106, 176
„ United States, 181
Ohm, his laws, 18, 133
„ on conducting power of metals, 124
Oldham, Explosion at, 239
Oliver, T., his report, 39
Oxidation, how to be avoided, 83
„ of copper less than that of iron, 131
„ of cylinder, 140
„ „ earth terminals, 131
„ „ surface of conductor unimportant, 73
„ „ terminals leads to failures of conductors, 131
Painted conductor, 69, 94, 99, 103, 113, 117
„ galvanized conductor, 139
Paint objected to, 67, 227
Palais de l’Industrie, Paris, its construction, 61
Paratonnerres, Traité des, 103
„ A Collin et Fils, Paris, 117
„ Nouveau par Jarriant, 111
„ par Jarriant, 115
Partial protection, 194, 244
Passage of electricity of tension in bad conductors, 141
Patterson, Mr., of Philadelphia, on good contact, 58
Payneshill, site of first conductor, 85
Pearson, J. L., his report, 39
Pegwell Bay, tide receded, 48
Pennycook & Co., their answer, 13, 14, 17
Perfect lightning conductor, 131, 186
Perforated iron pipe as earth terminal, 114
Perrott’s, M., experiments, 139
„ remarks on earth contacts, 140
Perry, Prof., on conductors, 132
Personal safety from Lightning, 233
Persons killed by lightning in France, 129
Perspiration from flock of sheep, a conductor, 48
Phillips, R., on atmospherical electricity, 98
Phin, John, on lightning rods, 102, 181
Phipson, R.M., account of destruction of Wells Church, 194
Pidgeon, Mr., discussion on earth connections, 131
Pierron, M., his proposal, 52
Pinnacles on church towers, 10, 29, 137
Pipes, gas, (_See_ GAS, WATER, and EARTH TERMINALS).
„ hard metal, as conductors, 108
„ iron, easily made into protectors, 102
„ of terra cotta, 180
„ rain-water, 34, 74
„ as earth terminal, 114
Plait of copper wire, 5, 9, 205, 210, 215
Planta, Mr., his report, 79
Plate, Earth (_See_ EARTH PLATE).
Platinum points, 37, 115, 140, 227
„ „ approved of, 15, 54, 55, 59, 63, 66, 99, 104, 116, 120
„ „ objected to, 67, 73, 103, 123, 139
„ „ only half the conducting power of copper, 73
„ „ blunted, 69
„ „ fused, 128, 231
Plymouth, Charles Church at, 86
Point Aigrettes (_See infra_ MULTIPLE).
„ attracts electricity, 82
„ blunted, 53, 69
„ breaks the force of lightning, 73
„ coronal (_See infra_ MULTIPLE).
„ dimensions of, 17, 18, 120, 130, 178
„ Duhamel upon, 66
„ Engravings of some modern ones, 230
„ facilitate discharge, 131
Point generally, 9, 17, 18, 76, 79, 81, 86, 92, 122, 125, 131, 139
„ gilded, 9, 55, 59, 71, 120, 138
„ „ needless, 73, 103, 113
„ height of, 52, 138
„ how to be fixed, 14, 52, 53, 55, 58, 130
„ _in situ_, examination of necessary, 18
„ melted, 53, 87, 92, 192, 195, 231
„ multiple, 34, 231
„ „ recommended, 10, 13, 14, 15, 23, 104, 108, 125, 132, 139, 243
„ „ objected to, 18, 71
„ not to be fusible, 93, 120
„ of attraction, 127
„ „ copper, 10, 13, 23, 66, 67, 107, 111, 117, 120, 123, 132, 139
„ „ iron, 88, 138
„ „ brass, 13
„ „ pinnacles to be united to main conductors, 118
„ „ platinum (_See_ PLATINUM).
„ „ silver, 7, 120, 130, 139
„ „ three kinds, 138
„ „ vane, 186
%center%(_See_ VANES).
„ or blunt conductors, 77, 79, 106
„ render lateral discharges less probable, 131
„ Report upon, 60, 66
„ sharp, 129, 130, 132, 138, 139
„ „ not too, 92, 123, 129, 242
„ „ experiments with, 51, 80
„ should be kept clean, 130, 132
„ „ of good conducting metal, 139
„ should it be painted? (_See_ PAINTED).
„ space protected by (_See_ PROTECTION, AREA OF).
„ square tapering, 23
„ used in Germany, fire gilded copper cone or sphere, 105, 111, 130
„ useful, 102, 122
„ useless, 77, 103, 113
„ vertical, horizontal, or perpendicular, 58
Poisson, M., his joint instructions, 59
Polarity of ship’s compass reversed by lightning, 121
Poles, Telegraphic, how protected, 101
Pouillet, M., his joint Report, 60, 66
„ on Conducting Powers of Metals, 124
„ „ Discharge of Lightning, 131
Powder magazines, 51, 52, 55, 56, 57, 66, 67, 70, 73, 74, 76, 81, 87,
109, 118, 123, 126, 130, 177, 178, 216
Preece’s, Mr. W. H., Abstract of Replies of Manufacturers, 22
„ Discussion on Lightning Conductors, 131
„ Discussion on Earth Connection, 131
„ Abstracts by, 98, 102, 117, 130, 132, 241, 243
„ on Conductors, 100
„ „ Ball Lightning, 101, 102
„ Paper Discussion on, 102
„ Proper Form of Lightning Conductors, 132
„ Space protected, 135
Priestly, Dr., his Report, 79
Pringle, Sir John, his Report, 79
„ advocated use of points, 122
Protector (_See_ CONDUCTOR).
Protection, Area of, 6, 9, 13, 15, 16, 21, 22, 24, 57, 60, 64, 67, 71,
73, 82, 87, 96, 102, 106, 111, 112, 117, 123, 125, 134, 135, 137,
180, 192, 226, 230, 243
„ of buildings from lightning, 195
„ „ buildings from lightning, R. S. Brough, 132
„ „ iron from decay by galvanizing, 132
„ „ telegraph wires by lightning conductor, 130
„ partial, 194, 244
Prussia, accidents from lightning, 126
Purfleet, Board House struck, 76, 78, 88, 122, 126
Purity of copper essential, 124
Quadrangular iron bar for conductor (_See_ IRON, BAR OF).
Questions respecting damage by lightning, 28, 29
Radius of Protection (_See_ PROTECTION, AREA OF).
Railings to be joined to conductor, 125
Railway Terminus at Antwerp struck, 137
„ track makes capital earth, 117
Rain-water pipe as conductor, 37, 38, 41, 132, 213
Rat, Wet, indestructible by electricity, 85
Ravel, M. de Puy Contal, his proposal, 52
“Reception rod” of iron used in Germany, 125
Regnault, M., his reports, 66
Regnier’s system of lightning rods, 54, 57
Regulations for lightning conductors in Denmark, 176
Repellers, Glass, 186
Resistance of conductor varies with its length (_See_ AREA, SECTIONAL).
Retarding influence of electrostatic capacity, 133
Return shock mechanical in effect, 129
Ribbons and tubes still in use, 133
„ or rods offer less resistance than ropes, 204
%center%(_See also_ TAPE.)
Richard & Co., their tall chimney struck, 44
Richmann, Prof., killed, 1753, whilst experimenting, 121
Ridges, metallic conductor covering, 68, 177
Rittenhouse, Dr., of Philadelphia, his observations, 53
Rivets, copper, used for joints, 24
Robins, E. C., his report, 39
Robertson, J., his report, 76
Rochon, M., his report, 51, 57
Rods better than ropes or chains, 96, 204
„ solid copper, 10, 13, 14, 15, 73, 89, 117, 123, 184, 195
„ copper not fusible, 125
„ copper, their size, 70, 180
„ Earth terminals of (_which see_).
„ elevation, how coupled, 24
„ horizontal, on roof, 52, 118
„ how to be fastened to buildings, (_See_ ATTACHMENT).
„ iron, conductor, 10, 46, 47, 77, 99, 117, 177
„ „ tarred or galvanized, 104
„ „ the size of, 52, 58, 70, 74, 130
„ Joints in (_See_ JOINTS).
„ Lightning, and how to construct them, 102
„ Munson’s, 216
„ must be thoroughly joined, 52
„ not to be inside chimney, 111
„ of greatest length gives most protection, 137
„ of spirally twisted iron, 192
„ Points of (_See_ POINTS).
„ should be painted (_See_ PAINTED).
Rods, size of (_See_ CONDUCTOR, Size of).
„ Tie, must be connected with conductor, 60
„ to be diameter of chimney above top, 111
„ to be made of conical form, 129
„ will not divert electric fire from its path, 125
Rome, system of rods used there, 179
Roof, all metals in, to be connected, 60, 72
„ covered with metal, 37, 69, 177
„ lead, easily made into protector, 102
„ of wood or slate has conductor on ridge, 125
„ with masses of metal, difficult to protect, 7
Rope better than rod, 5, 10, 60, 111, 113, 131, 243
„ brass wire, 60, 124
„ conductor, how to fit to ship’s rigging, 6
„ „ lower end of to be opened, 11, 15
„ copper and zinc wire decayed, 205
„ copper better than iron for towns, 19
„ copper, its advantages and disadvantages, 8, 56, 63, 131, 134
„ copper wire, 10, 13, 14, 34, 37, 39, 60, 75, 103, 125, 131, 225,
226, 227
„ „ dimensions of, 8, 9, 223
„ „ has both surface and mass, 16
„ „ too expensive, 58
„ easily bent without angles, 19
„ „ joined, diverted, or lengthened, 19
„ hemp, for conductors, 56
„ Iron wire, 19, 58, 68, 125, 227, 243
„ „ „ smashed, 86
„ liable to corrosion on factory chimneys, 125
„ of thick copper wire, 226, 229
„ or cable, fringed out at upper terminal, 14
„ metallic, disadvantages of, 62, 63, 95, 204
„ for connecting points with metal bars, 55
„ with hemp strand in middle, 116, 227
„ Wire, conductor, badly erected, 39
„ damaged, 193
Rosherville Church struck though provided with a conductor, 34
Rounded and pointed conductors, 79
%center%(_See_ POINT.)
Route to earth for conductor, 126
Royal Society, Committee of, 76, 78, 79
Rules for erecting Conductors
%center%(_See_ INSTRUCTIONS).
Russell, F. & Co., their answers, 9, 17
Rust increases electrical resistance, 70, 107
Sacré’s, M. E., system, 140
Safety from Lightning, Personal, 233
St. Ann’s Hotel, Buxton, struck, 34
St. Aubyn, J. P., 29
St. Clotilde Church, Paris, struck, 69
St. Eloi Church, Paris, struck, 69
St. George’s, Leicester, 126, 240
St. James’ Church, West-End, Hants, struck, 34
St. Mary’s, Crumpsall, near Manchester, struck, 39
St. Mark’s, Venice, 103
St. Matthias’s Church, Brixton, struck, 39
St. Michael’s Church, Stamford, struck, 43
St. Paul’s Cathedral, Accident to, 78
„ „ fitted with copper wire rope, 131
„ „ its immunity from injury by lightning, 103
St. Peter’s Church, Brighton, pinnacle struck, 48
St. Sepulchre’s Church, Northampton, struck, 37
St. Sulpice Church, Paris, struck, 69
Sanderson & Co., their answers, 23, 24
“Scientific American,” 118
Screen, metallic, a protection, 85
Secchi, P., 180
Sectional Area (_See_ AREA, SECTIONAL).
Sharp Points (_See_ POINTS).
Sheets, Iron, struck, 53
Sheet lightning is the reflection of forked, 101, 242
Ships struck, 53, 61, 62, 88, 95, 195, 205
„ conductors, 6, 90, 121, 122, 195, 199, 200
Short terminal points to chimneys, 125
Siemens, A., abstract by, 127
Silver Points (_See_ POINTS OF SILVER).
Simmons, J., his Essay, 81
Size of conductor (_See_ CONDUCTOR, SIZE OF).
Small conductor replaced by heavier one, 194
Smoke discharged from chimney a conductor, 132
Smoke often destroys brass, 124
Snell, H. S., his report, 39
Soil, change in nature of, its effect, 71
„ dry, a non-conductor, 70
„ metallic veins beneath, 61
„ water beneath will attract lightning, 61
Soldered joints (_See_ JOINTS).
Solder, objectionable, 16
„ the use of, imperative, 20
„ „ not universal, 20
„ with copper, 103
Solid rods superseded by ropes of wire (_See_ ROPES), 131
South Foreland Lighthouse, 185, 186
Spagnoletti, Mr., discussion on lightning conductors, 131
Spang, H. W., Treatise on Lightning Conductors, 112, 181
Sparks from Holtz’s machine, 141
„ „ Ruhmkorff’s coil, 141
Space protected (_See_ PROTECTION, AREA OF).
Specific attraction, equal in all bodies, 73
„ heat of iron greater than copper, 132
Sphere, Metal, on top of conductors, 111
Spike of iron (_See_ POINT).
Spiral twisted iron rods, 192
Spires, Church, conductor for, how fixed, 23
Spire, Church, conductors for without joints, 24
Spires, connection from bottom of vane rod, 14
Spout, Iron, entered by lightning, 43
Spout split at joints, 45, 46, 47, 49
Spratt’s patent conductors, 205, 210, 215
Spurn Point High Light, 184
Square building to have terminal at each end, 125
„ wire, 13, 216
Staples for attaching conductor (_See_ ATTACHMENT).
Static discharges from conductors, 133
„ electricity, laws of, 132
Stays, Metal, 184,185
Steeple of Jacobi Church, at Hamburg, 129
Steeples to have horizontal conductors, 113, 125
Steeple with lightning rod injured, 124, 125
Steinheil’s lightning protector, 130
Sterriker, John, his report, 45, 46
Straps and nails (_See_ ATTACHMENT).
Strasbourg, accident at, 99
Straw conductors for country use, 104
Strata, water bearing, connection to be made with (_See_ EARTH
TERMINAL).
Stream of fire in rigging of ship, 54
Striking distance, 650 to, 6500 feet, 108
Stroke, lightning, 9 or, 10 miles, 108
Sullivan, Adml. 183, 195, 199
Sulphur Paste made of galena and melted, for end of conductor, 58
Sulphurous fumes destructive to terminals, 131
„ odour of lightning, 85
Sun burner to lofty building, 201
Superficial conductors, advantages of, 86
Supports of protector soldered with zinc, 140
Supposed perfect conductor, 131
Surface exposed to air considerable, 139
„ or mass, which conducts?, 13, 15, 18, 49, 74, 89, 132
Swan Cotton Mill, 239
Sweden, accidents from lightning, 126
Symons, G. J., 43, 46, 183
„ abstracts by, 74, 89, 99, 102, 104, 111, 115, 131, 132, 134, 135
Tacchini, Prof., 179, 180
Tait, Prof., on thunderstorms, 241
Tanks, 15, 71, 94, 107, 130
Tape, joints, if any, should be rivetted and soldered, 7
„ copper better than rope, 8, 204
„ „ objections to, 5, 6, 16
„ „ let into masts, 92
„ lower end to have a discharging fork, 11
„ Phin, upon, 103
„ to be cut in strips for earth terminal, 15, 23
„ copper, the sizes and lengths made, 7, 10, 14, 23, 70, 133
„ cheaper than rope, 8, 9
Tarred casing of wood to enclose iron, 125
„ metallic rope, 60
Taunton Church, large copper rope conductor, 8
Teale, F. G., of Calcutta, 181
Telegraph instruments injured, 100
„ poles, how protected, 101
„ wires affected underground, 101
Temperature, variations of, affecting length of conductor, 68, 125, 226
Terkelsen, C., abstract by, 106
Terminal area protected by (_See_ PROTECTION, AREA OF).
Terminals (_See_ POINTS).
Terminal, earth (_See_ EARTH TERMINAL).
Terminal for every, 20 ft. of roof, 125
„ how fastened to roof, 52
„ if numerous, should have proportionately thicker conductor (_See_
AREA, SECTIONAL).
„ long upper, 68, 77, 225, 229
„ jar roof by vibration by wind, 116, 127
„ not always pointed, 92, 125
„ painted or tinned, 55
„ rods, 17, 55, 66, 67, 72, 124
„ „ to branch out at top
%center%(_See_ POINTS).
„ Upper, how attached to conductor, 60
„ „ fused, 193
„ „ should be cased in lead to protect from sulphurous fumes, 131
„ „ to be a round rod, 125
„ „ to be iron or copper, 82
„ „ too small, 62
„ „ what it is, 59
„ „ what made of, 13
Terra Cotta water pipes, 180
Testing apparatus, 111, 225, 228, 243, 244
„ of building as well as of conductor, 9
„ of conductors with galvanometer, 9, 131
„ to be periodical, 132, 244
Theory of protection (_See_ PROTECTION, AREA OF).
Thimbles, glass, 186
Thomson, Prof. Sir W., on conductors, 47, 48, 49, 102, 133
Thunderstorms dangerous where no woods are, 119
„ in France, 1822, 123
„ nature of, 85
Ties, Metallic (_See_ ATTACHMENT).
Tin and lead conductors tried, 123
Tinfoil, experiments with, 199
Tinned metallic wire, 95
Tips (_See_ POINTS).
Tomes, J., F.R.S,, accident to his house, 210
Top conductor (_See_ CONDUCTOR RIDGE).
Torquay, no good earth there, 130
Tower of church struck, 29
„ of house struck, 37
Trees bad conductors, 127
Trees, High, their protective action, 85, 127, 243
„ injured while passing lightning to better conductor, 127
„ on plains attract lightning, 127
„ struck, 45, 47, 49
Trenches, Connections in, 72
„ filled with carbonaceous materials, 7, 12, 100, 125
„ in rocky or dry soil, 72
(_See also_ EARTH TERMINALS).
Trough, Oaken, for lower terminals to pass through, 56
Trinity House, 183
Tube conductor for Houses of Parliament, 199
„ Copper, 7, 10, 14, 70, 74, 133
„ „ having copper cable passing through it, 13
„ patent insertion joints, 7
„ Iron, 86, 117
„ conductors, why objectionable, 5
Turrets, conductors for, how fixed, 23, 24
Twyford Moors, near Winchester, 34
Underground connection (_See_ EARTH TERMINAL).
United States, accidents from lightning, 126
University Coll., Chimney struck, 38
University of Padua protected by conductors, 122
Upper terminal (_See_ TERMINAL UPPER and POINTS).
Upwood Gorse, Caterham, accident at, 210
Vaillant, Le Maréchal, his Report, 66
Vanes, how connected, &c., 10, 11, 14, 23, 39, 40, 52, 53, 104, 183,
185, 186, 202
Varley, C., quoted, 101
Venetians decreed to use lightning rods in Republic, 122
Ventilating pipes, 216
Vitreous tubes (Fulgurites) formed by electricity, 112
Vyle’s, S., rod & testing apparatus, 244
Walker, C. V., on conductors, 84
„ on Leyden discharges, 84
„ J., 187
„ Matthew, His knot, 16
Wall eyes of iron, 130
%center%(_See also_ ATTACHMENT).
Wandsworth, chimney of house struck, 38
Ward, G. G., of New York, 181
Water mains and underground water generally (_See_ EARTH TERMINALS).
Water spouts to be connected, 10, 226
Watson’s, Dr., conductor at Payneshill, 85
„ „ for ships, 121
„ report, 76, 79
Weathercock (_See_ VANES).
Weber, Dr. L., on lightning discharges in Schleswig Holstein, 127, 231
Week, St. Mary, the Church of, 29, 30
Weight of conductors (_See_ CONDUCTORS, SIZE OF).
Wells (_See_ EARTH TERMINALS).
Wells Church, Norfolk, destruction of, by lightning, 194
West side of house, rod to be on, 100
Wheatstone quoted, on fusion of rod, 83
Whichcord, J., his joint Report, 28
White, W. H., Secretary R.I.B.A., circular signed by him, 28
Wilkins & Weatherby, their answer, 4–6, 17
Wilson, Mr., his report and views, 76, 79
Wilson, R., on conductors on chimneys, 110
Wind, action of on conductors, 116, 127
Windmill with conductor struck, 128
Windows, copper, to magazines, 74
Winkler, Prof. J. H. (1746), electricity cause of thunderstorm, 129
Wire cables (_See_ ROPE).
„ cage as protection without use of earth, 132
„ melted into drops like shot, 195
„ of zinc melted, 107
„ rusted in earth and was useless, 107
„ square, 13, 216
Withers, J. B. M., his report, 40
Wood to be creosoted to form case for iron, 125
„ coated with resin, as a conductor, 54
Workhouse, how to be protected, 10
Wrexham Church struck, 126
Wrottesley, Col. G., R.E., his report, 40
Wrought iron (_See_ IRON).
Wyatt Papworth Church struck, 39
York, accident at, 219
Zenger’s, Prof. C., Symmetrische Blitzableiter, 104
Zinc better conductor than iron, 74
„ coating, 72
„ chimney of house struck, 37
„ cylinder, wire to pass through, 83
„ strips, 192
„ wire melted, 107
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TRANSCRIBER’S NOTES
1. P. 170, changed “Annals of Electricity. 10 vols. 8vo. 18363–4” to
“Annals of Electricity. 10 vols. 8vo. 1836”.
2. Silently corrected typographical errors and also variations in
spelling.
3. Retained anachronistic, non-standard, and uncertain spellings as
printed.
4. Enclosed italics font in _underscores_.
5. Enclosed bold font in =equals=.
6. Enclosed small font in ¤currency signs¤.
7. Superscripts are denoted by a caret before a single superscript
character or a series of superscripted characters enclosed in
curly braces, e.g. M^r. or M^{ister}.
8. Subscripts are denoted by an underscore before a series of
subscripted characters enclosed in curly braces, e.g. H_{2}O.