Lightning

Lightning

An Authority Writes on this Fire Hazard

The lightning discharge was, undoubtedly, the first electrical phenomenon observed by mankind, but all its actions have only recently been determined.

Among the phenomena observed by the ancients is the great attraction of lightning discharges for oak and similar trees that have great out-spreading branches. To this, reference was made by Greek writers over twenty-two hundred years ago. Similar phenomena have also been observed in every age. They puzzle even our present scientists, who are not aware of the fact that the great lightning attraction for trees is due to their radiating roots, which enable the opposite electricities (positive and negative) to readily unite.

Nature has provided lightning discharges for our welfare. They combine gases held in suspension and produce chemical agents which are essential for the growth of vegetation and plants. They also generate ozone, which neutralizes the miasma of the air and thereby prevent epidemics. Emerson truly said: “The air would rot without lightning.”

The Franklin Lightning Rod

After describing in a letter dated July 29, 1750, to Mr. Peter Collinson, the London agent for the Library Company of Philadelphia, an experiment in which a pointed punch had harmlessly conducted electricity between two small metal scales, artificially charged, to represent the clouds and the earth, Franklin suggested that pointed lightning rods be placed on houses, churches, ships, etc-, and adds: “Would not these,points probably draw the electrical fire silently out of the cloud before it – came nigh enough to strike, and thereby secure us from that most sudden mischief?”

After an experience of about fifteen years with lightning rods it became apparent to Franklin that a pointed metal rod could not perform the function of silently tapping the electricity contained in a cloud and preventing lightning discharges in the vicinity of the building to which it is applied.

The lightning rod, as installed in Franklin’s time and up to the time of the introduction of water and gas pipes into buildings, was a fair success as a lightning conductor, for the reason that in the early days of the lightning rod, the atmospheric electricity in flowing to the earth divided into a number of branches, of which the lightning rod received one branch and adjacent trees and other objects received the other branches.

With the introduction of underground water and gas pipes, steam railroads, electric telegraph and other overhead electrical circuits, also wire fences, there has been a change in the lightning discharge and especially in the area of the terrestrial electric charge, which also participates in such discharge.

Faraday Could Not Interpret Lightning

There is no subject upon which more nonsense has been written and which is as imperfectly understood as the lightning discharge. This is due to the neglect or inability of college professors to properly investigate and interpret the effects of lightning discharges. They have relied almost solely upon laboratory electrical experiments which are not analogous to the lightning discharges.

Even Faraday could not properly interpret the electrical conditions and actions attending the lightning discharge. In 1863, after retiring from the Royal Institution of England, he stated in a letter that “Lightning is a very curious thing,” thereby admitting that it puzzled him. In his letter he also stated that the atmospheric electricity in line with a tree alighted upon all the branches and concentrated upon the trunk, and compares such action to an ordinary laboratory brush discharge.

In formulating this erroneous theory he was solely governed by the shattering of the bark of the tree, which he had observed on several occasions and by his laboratory experience.

I have investigated the effects of lightning discharges since 1858, and have only been able to determine the true action of the atmospheric electricity in line with a tree by numerous phenomena, such as the killing of persons and animals beneath a tree without damaging its trunk. Also by the division of the atmospheric electricity into several main branches, one in line with tree and others in line with adjacent building, wire fence, hay stack or other object. Its true action is the opposite of that theorized by Faraday.

Erroneous Metal Cage Theory

In a paper on Lightning and Lightning Protection read by Prof. C. P. Steinmetz, before the National Electric Light Association, June, 1907, after referring to the suggestion of the lightning rod by Franklin, he adds:

‘The next step in advance was made by Faraday; he showed that in the interior of a perfectly conducting body no electric disturbances can be produced by outside electric forces. This led to the most effective protection possible against lightning or electric disturbances, the use of the grounded metal cage, Faraday’s cage, enclosing the structure which is to be protected, whether a building against lightning, or a delicate instrument against electric fields.”

I have found from practical experience that a metal cage is not essential for absolutely protecting a building or other structure against lightning. In my first work on Lightning Protection issued in 1877, 7 refer to the failure of the metal cage to protect oil tanks. A number of cases can be cited of chickens in wire cages being killed by lightning. The steel framework of the modern skyscrapers and other large buildings is a metal cage. Interior lightning flashes and panics, impaired sprinkler heads, also impaired insulation of interior electric light and power wires by lightning discharges in line with such buildings are quite common. This is another case where a laboratory experiment fails to reveal the true action of the lightning discharge.

I have found that the true place to catch the lightning in a rural section is at a point or points away front the building or other structure to be protected. Phis plan has been successfully tried since 1901 at various places within 75 miles of New York City.

Henry and Lodge

The only contributions to the lightning science made in the last century were by Prof. Joseph Henry, the eminent American scientist and thinker. He had a far better conception of the lightning discharge than Faraday or Prof. Oliver J. Lodge, of England. He maintained that the lightning discharge consisted of a series of discharges and while experimenting with needles in a spiral located between the metal roof of his house and the ground at Princeton, N. J., in 1845, he found that these was an apparent interval between the discharges. His contention is now fully confirmed by the revolving camera, by which not only the number of discharges but also the time intervals between them are determined.

The first telegraph line between Philadelphia and New York was struck by lightning on May 20, 1846, at a high pole at the Hackensack River and shattered the poles at intervals within a mile upon each side of that point. During another storm shortly afterward about twenty poles were shattered. Prof. Henry suggested that a lightning rod be applied to each telegraph pole.

Prof. Henry, in 1842 discovered electric oscillation when the Leyden jar is discharged into a wire forming a metallic circuit. He was too careful a scientist to claim electric oscillation and self-induction in the lightning discharge, all that Prof. Lodge has done has been to attribute to the lightning discharge phenomena which Prof. Henry clearly showed were only possible in a wire circuit.

Professor Lodge also revived the old exploded metal cage principle of lightning protection, first suggested by Clerk Maxwell and based upon a laboratory experiment made by Faraday. This improper suggestion was adopted in 1907 by the National Fire Protection Association of this country for protection of buildings against lightning.

The Overhead Ground Wire Protector

In 1883 I patented the grounding of wire fences at intervals for rural lightning protection purposes. This method is now successfully employed in the West for the lightning protection of cattle, which congregate adjacent to wire fences during thunderstorms.

Such success completely refutes the following statement made in 1907 by Prof. C. F. Steinmetz and fully proves that the metal cage principle of lightning protection is not necessary for overhead high transmission and other electrical wires and their supporting poles. He said: “In its simplest form, Faraday’s cage, applied to a transmission line, is the ground wire above the line, and the protection afforded by it is the more complete, the more the overhead ground wires represent the condition of an enclosing cage of perfect conductivity. That is, a system of wires above and on the sides of a transmission line is superior to a single wire, a wire of high conductivity superior to a small iron wire-”

I will add that a substantial overhead horizontal iron wire or cable, properly connected with the earth, will afford greater protection than a multiplicity of horizontal copper wires improperly connected with the earth.

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Lightning

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Important Lightning Discoveries

I have found that Nature is methodical, not only in the lightning discharge, but also in thundercloud formations.

Such formations are greatly influenced by the great lakes, rivers, sounds and other waterways, also by railways and long water, gas and oil pipe lines, located east and west.

In city of New York, also Long Island, Southern New York and Connecticut, they are partially influenced by Long Island Sound, upper and Tower New York Bays, also Jamaica and Great South Bays.

The method of the lightning discharge is partially indicated by the great attraction of the opposite electricities (positive and negative) in a lightning discharge for hay, grain, tobacco, cotton, ice and other greatly and compactly stored material, over which they can readily unite. For the same reason, they have a great attraction for underground water, gas and other metal pipes and structures, embracing the metal subway tubes in City of New York, also for railway tracks, wire fences and all overhead and underground electrical wires.

In connection with the lightning destruction of the electric light generating plant during November, 1900, upon the Henry Villard estate at Dobbs Ferry, N. Y., I discovered the true position of the terrestrial electric charge during a thunderstorm and the true relation of the atmospheric electricity with such charge. Through this discovery, lightning protection of buildings and all structures, embracing electrical circuits, is now reduced to a positive and correct science. Scepticism of such protection is no longer justified.

LIGHTNING.

LIGHTNING.

Elihu Thomson, of the General Electric company, of Lynn, Mass., an expert on the subject of lightning and protection against lightning, says that no one yet knows how lightning occurs. All that seems to be positively known is that there are certain periods when lightning storms are of great frequency. These periods come about eleven years apart, and are coincident with the periods during which the aurora borealis occurs. At such times the sun sends out electrified rays, and, if the earth happens to be the target, electrical storms are very frequent and severe. This is only one form of electrical storm, however, as they follow volcanic eruptions and other disturbances. Lightping storms arc caused by the condensation at high altitudes of warm air rising from the earth. Clouds are thus formed, and the clouds are positively electrified, and the earth is negatively elec trified. The atmosphere between the earth and the cloud is broken down at its weakest part, and the positive and negative forces unite. The lightning discharge follows this weakened part of the atmosphere to the ground. The damage is occasioned by the explosive effects of sudden heating The material struck vaporises, and, in the case of wood, the moisture, suddenly vaporised, sets fin.