“ It is necessary also that every workman should remember that in placing a lightning conductor he holds in his hands the lives of men, that he should feel conscientiously interested in the perfection of his work, and, finally, that he should feel that it is a mission which he fulfils, and not a mere matter of trade at which he works. ”

“ But it is beyond controversy that a good conductor is absolutely harmless to all surrounding objects, and a man might lean against a copper half-inch rod, carrying off a heavy stroke of lightning into “good earth,” without being aware of its passing.
It is useless and dangerous to isolate conductors from buildings. All masses of metal should be connected with conductors. ”

“ The danger to men and animals from the effects of lightning arises from the fact that the bodies of living animals form comparatively good conductors of electricity,—better, that is, than rain-water (probably better even than sea-water) , or than trees, walls of brick or stone, hay-stacks, or in fact than almost any common objects consisting of non-metallic materials. It may be assumed that the path of a lightning-discharge striking the earth is determined by the line of least inductive resistance between the thunder-cloud and the earth. ”

“ At present we have not sufficient data to enable us theoretically to calculate the space protected by a lightning rod, and therefore we are compelled to draw up our rules upon the question entirely from experience, and here we find, that with the doubtful exceptions already mentioned, there is no recorded instance of a building being struck by lightning within a conical space, the radius of whose base was equal to its height, and we think that the adoption of this rule may reasonably be expected to yield that security in the future, which as far as we know, it has done in the past. ”

“ In the case of two buildings alike in size and shape, situated on the same soil, one made of wood and stone as formerly, the other with much metal as now, and both without lightning rods—if the conditions are such that the lightning must discharge itself, it will always strike the latter, and never the former; in the same way as on bringing to the conductor of an electrical machine a ball of wood or stone, and one of metal, it is always the latter which will receive the spark. ”

“ We are not able, even at immense expense, to make the earth connections so large as to compete with the conducting power of metallic gas and water-pipes, the total length of which is frequently many miles, and the surface in contact with the moist earth is thousands of square miles. Hence the electric current prefers for its discharge the extensive net of the system of pipes to that of the earth connection of the rods, and this alone is the cause of the lightning leaving its own conductor. ”

“ If there was a conductor, state its dimensions—construction—mode of attachment to building—whether its top was pointed—distance of its upper terminal from the place struck—nature and extent of the connection between the conductor and the earth, and whether the earth was dry or moist—whether the conductor was itself injured—and whether the conductor or the point struck was the most salient object in the vicinity. Information is also desired, either verbally or by sketches, as to the position of metal spouting and lead roofing relatively to the point struck, and to the conductor. ”

“ Metallic bodies have no specific attraction for electricity more than wood or stone have; all matter is indifferent so far as regards a specific attraction. Lightning falls indiscriminately upon trees, rocks and buildings, whether with metals about them or not; e.g., at Plymouth Dockyard in May, 1841, a granite chimney, 120 feet high, without any metal in it, was struck, and yet it was within 300 feet of a clock-tower of equal height, having metal weathercock, a dome covered with metal and large conductor along it to ground. ”

“ Metal in Buildings.—Taking the conductivity of copper as from 7 to 10 times greater than that of iron, it would probably follow, that if two rods, the one of copper the other of iron, in these proportionate sizes, were brought together in one common terminal or point, and led by the same course to the earth, as much of the fluid would possibly pass down the one as the other. On this principle, we avoid contiguity with any metal in a building, especially if in large masses, such as machinery, &c. ”

“ If the water-pipes in Basel had been joined with lead instead of pitch, no mechanical effect could have been produced. The mechanical effect of an electrical discharge is greatest where the electric fluid springs from one body to another. The wider this jump the more powerful is the mechanical effect. The electrical discharge of a thunder cloud upon the point of a lightning rod may melt or bend it, while the rod itself remains uninjured. If the conductor, however, is insufficient to receive and carry off the charge of electricity, it will leap from the conductor to another body. ”

“ Professor Jenkin’s statement, that if a conductor be armed with a point, the electricity passes into the air rapidly in times of excitement by induction, and so equalises the tension of the surrounding atmosphere as to mitigate, or, in some cases, to prevent the discharge of lightning.
2. De la Rive’s observation that a slight break of continuity in a conductor is filled by a succession of brilliant sparks during a storm, though there be no lightning; that blunt points or balls are equally effective when struck, but are more usually accompanied by explosion than by continuous discharge. ”

“ The connection to the earth should be as perfect as possible—in cities nothing is better for this purpose than to unite it to the gas or water pipes. When a connection cannot be formed in this way the rod should terminate in a well containing water, or if this is not practicable it should terminate in a plate of iron, or some other metal buried in moist ground. It should, before it descends to the earth, be bent, so as to pass off nearly at right angles to the side of the house, and be buried in a trench, surrounded with powdered charcoal. ”

“ There is more profit to be made out of the copper rod, as it is made cheaply out of sheet copper, and can be sold much higher than the iron rod. But knowing that iron for all practical purposes is the best material for lightning rods, we feel it to be our duty to do all we can to introduce it. We would most respectfully ask the Conference to investigate this question as to what kind of metal is best for rods for practical use, iron or copper. ”

“ Hence, a man standing on an open plain, or walking, or riding on horseback, or in an open vehicle, across it, is liable to be struck by lightning. There is no evidence that the motion of walking or riding makes the liability either greater or less than it would be if he were at rest. The danger is increased, other conditions being the same, by nearness to water, or to large masses of metal, or other conducting material, lying flat on the ground or rising only a little way from it. ”

“ It is no uncommon thing for buildings provided with what are called lightning conductors to be damaged by lightning, and the cause is due to the inadequacy of the conductor to carry the electric fluid, which will leave the conductor for a better or a larger conductor. Wire ropes are found to be one of the worst forms, the same amount of metal when applied in a solid rod or ribbon is far more efficient, as it offers less resistance than the strands of a rope. ”

“ Conductors of small iron rod or wire are very objectionable. They commonly rust at the joints, and have fallen to pieces, and often been knocked to pieces by lightning. Iron may, certainly, be employed with advantage, but should be galvanized. Zinc is an even better conductor than iron; and being spread over the surface is not open to the objection of making a conductor of two metals of unequal conducting power. A good and efficient conductor might be formed of galvanized iron. It should be of wrought iron, galvanized, of 2 inches diameter, with screwed joints of extra thickness. ”

“ So long as these are connected with the ground, he prefers that the projecting rod should be of round iron of considerable length and in one piece, and the conducting cable should wind round it as a collar, and be strongly attached to it by set screws and soldering. He does not advise that all the masses of metal within a building should be connected with a conductor, especially if they are in proximity with human beings, but with a well-made conductor he considers it safer to leave them isolated. ”

“ 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. ”

“ In conclusion, we beg to state that our patent system of protection is the application of one or more main down and ground copper conductors and sizes, according to the height and area of the building, the fitting of the copper bands to each chimney-stack, and connecting the same, and the connecting of all the metals on the roofs thereto and to the main conductor, so that there shall be no circuit by which the lightning fluid would be likely to attack without having its exit to the main conductor. ”

“ Angles and Joints.—It must be obvious to any one that lightning, as well as any other matter or thing which travels at high speed, would be greatly obstructed in having to turn corners. It must also be borne in mind that lightning is of intense heat, and while passing in a straight line the effect of its heat is lost in the velocity of its motion; but in passing an angle its momentary pause (much too brief to be calculated) is sometimes enough to create sufficient heat to fuse the conductor at the angle. ”

“ 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. ”

“ That it is important casual arrangements should never be depended upon for lightning conductors; but a copper rod be established for the especial purpose: for, if the former be trusted to, the carelessness or ignorance of workmen may, at after periods, upon occasions of repair or cleansing, cause the necessary metallic connection to be left imperfect or incomplete, and then the arrangement is not merely useless but dangerous. ”

“ As to origin of atmospheric electricity, De Saussure considered it due to the evaporation of water by the sun’s heat. Peltier (1765–1845) considered the earth itself to be one immense reservoir of electricity. As light comes from the sun, so electricity is generated by heat from the interior of the globe. No electricity is produced by atmosphere, nor held by it, except temporarily.
There is no recorded case in which a well made lightning rod, with “good earth,” did not do its duty. ”

“ 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. ”

“ One fact that occurred in 1837 is given as a reason for their use, but the fact militates against the efficiency of the conductor rather than the absence of insulators. If the conductor were perfect there could have been no concussion at the point of attachment. If it were imperfect there may have been, for the discharge would seek other paths to earth. Some manufacturers use holdfasts of a different metal to that of the conductor. This is wrong, for where different metals are used galvanic action sets in, tending to decay and rupture. ”

“ 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. ”

“ If the ramparts dominate the magazine it will be prudent to set upon them a lightning rod on a mast. Trees are only struck by lightning because their tops serve as points but their trunks are bad conductors, hence it is prudent not to have plantations, especially of lofty trees near magazines. However many points may be set up on a magazine they should all be connected together, and all joined to the principal conductor, and it would be well to have more than one principal conductor so that if one loses its continuity the lightning may have a path by the other. ”

“ For instance, a man may with perfect impunity clasp a copper rod an inch in diameter, the bottom of which is well connected with moist earth, while the top of it receives a violent flash of lightning. But if the electricity does not find a path prepared for it, it will utilise such partial conductors as may be reasonably near, for example—the heated air from a kitchen chimney, the soot inside, and then the metal range at the bottom ”