Lightning.

ning, which makes so many different centers of sound, at different angles with each other, the waves coming from which interfere with each other, at one time moving in opposite directions and obliterating the sound, at another in the same way, and then strengthening the sound produced by each. Thunder has never been heard more than 14 m. from the flash. The report of artillery has been heard at much greater distances. It is said that the cannonading at the battle of Waterloo was heard at the town of Creil, in the n. of France, about 115 m. from the field.

LIGHTNING (ante). The abbé Nolet is said to have been the first to remark the similarity of phenomena in discharges of lightning and of the electrical machine, but there was no experimental determination of the identity of their nature until Benjamin Franklin made his celebrated investigation of the subject by the use of a kite at Philadelphia in 1752. Three years previous to this, however, he made some interesting remarks upon the subject in his Observations on Electricity, showing that his mind had comprehended the causes even before he made his demonstrative experiments. He says: "Where there is a great heat on the land in a particular region the lower air is rarefied and rises; the cooler, denser air above it descends; the clouds in the air meet from all sides and join over the heated place; and if some are electrified, others not, lightning and thunder succeed and showers fall. Hence, thunder gusts after heats, and cool air after gusts. As electrical clouds pass over a country, high hills, trees, towers, chimneys, etc., draw the electric fire, and it is therefore dangerous to take shelter under a tree during a thunder gust. It is safer to be in the open fields for another reason. When the clothes are wet, if a flash, in its way to the ground, should strike your head it may run in the water over the surface of your body, whereas if your clothes were dry it would go through the body." Again: “Now, if the fire of electricity and that of lightning be the same, as I have endeavored to show in a former paper, and a tube of only 10 ft. long will discharge its fire at 2 or 3 in. distance, an electrified cloud of perhaps 10,000 acres may strike and discharge on the earth at a proportionally greater distance." Speaking. of the discharging power of points he says: May not a knowledge of this power of points be of use to mankind in preserving houses, churches, ships, etc., from the stroke of lightning by directing us to fix, on the highest parts of those edifices, upright rods of iron made sharp as a needle, and gilt to prevent rusting, and from the foot of the rods a wire down the outside of the building into the ground, or down round one of the shrouds of a ship, and down her sides till it reaches the water? Would not the pointed rods probably draw the electric fire silently out of the cloud before it came near enough to strike, and thereby secure us from the most sudden and terrible mischief?" He proposed various experiments, and, acting under his instructions, Dalibard had drawn electric sparks from an iron rod 40 ft. high at Marly in France, and had charged Leyden jars with the apparatus, May 10, 1752. Franklin did not make his kite-experiment till more than a month later, viz., June 15. It was natural that these experiments should be repeated all over the civilized world. Prof. Richman of St. Petersburg was killed, in the summer of 1753, by a bolt of lightning in the form of a blue ball as large as a man's fist which leaped from the insulated conductor to his head, which was about a foot distant. His companion was struck senseless and a door was torn from its place by the stroke. In the experiment of M. Romas of Nerac, France (see ante), which has been said by some to antedate Franklin's, he used a kite of about 18 sq.ft. surface, with a copper wire wound around the string, and an insulating silk cord at the ground end, near which an iron tube was placed as a secondary conductor. When the kite was at a height of 550 ft. during a storm, flashes of fire darted to the earth attended by loud explosions, and all light bodies in the vicinity were alternately, positively and negatively, electrified and propelled in various directions.

It has been shown by Cavallo, De Saussure, and others that the electrical condition of the atmosphere, in comparison with that of the earth, is positive; also, by Laplace, Lavoisier, Volta, and De Saussure that the cause of atmospheric electricity is evaporation from the surface of the earth; but, according to the experiments of Pouillet, evaporation does not produce opposite electrical conditions unless accompanied by chemical decomposition or separation of vapor from saline solutions, or from oxidizing surfaces or the leaves of growing plants. Currents of wind rushing over opposing objects, occasioning disturbance of electric equilibrium, are among the chief causes of atmospheric electricity, the electricity passing with the wind to elevated regions; or, on the two-fluid hypothesis, positive electricity being carried upwards, while the negative passes to the earth. In regard to the production of the various kinds of lightning and thunder, they may be explained according to a variety of circumstances. To account for the variations in tone and intensity of a thunder-clap as heard at a certain pointthat is to say, to explain what conditions were present and what form or dimensions the discharge had-would be very difficult, perhaps impossible, from the fact that it is impossible to appreciate the extent of the process and the direction of the discharge or discharges. The reverberation of sound may be the result of one discharge, which is echoed from peak to peak or from crag to crag and probably from cloud to cloud, although the power of clouds to reflect sounds has not been determined. There may be a succession of discharges from different portions of different clouds to those of others, one explosion being succeeded by another in consequence of changes of electrical con

Lightning.

ditions in various parts of the celestial and terrestrial apparatus. The increased intensity of a roll of thunder is probably to be accounted for in this way. The first sounds may be produced by successive minor discharges, causing electrical conditions between two large masses of clouds, or between a large mass and the earth, which result in the exchange of large quantities of electric fluid, or the descent of a powerful bolt to the earth. Although many phenomena of electricity are well known, and the electricity of chemical batteries can be measured and rendered serviceable, still its real nature is not known. It is not positively determined whether it is an imponderable body, an imponderable force, or merely a phenomenon resulting from the conditions of the matter with which it is connected. Until its nature be determined it cannot be said whether a ball of lightning is a moving mass of electrical matter, or of other matter in a peculiar electrical state. There is something wonderfully interesting and inexplicable in some of these moving masses of apparent fire. The ordinary laws of electrical attraction and repulsion will scarcely serve to explain their various freaks. They often seem as if propelled from behind, in the manner of an ordinary projectile; and the manner in which they pass into dwellings and demolish walls may indicate that they are driven against bodies, and not attracted by them.

LIGHTNING, ACCIDENTS FROM. According to the registrar-general's report of births, deaths, and marriages for the year 1871, it appears that during that year 28 persons were killed in England by lightning: none in London, 5 in the south-eastern division, 6 in the south midland, 1 in the eastern, 1 in the south-western, 2 in the west midland, 6 in the north midland, 4 in the north-western, 2 in Yorkshire, and 1 in the northern division. All except 5 were men, and chiefly laborers in the open air. In 1875 17 persons were killed; in 1877 only 10. Of 24 deaths from this cause in a previous report, 11 took place in summer, 10 in spring, 2 in autumn, and 1 in winter. Out of 103 deaths in 5 years (1852-56), there were 38 in July, and 22 in Aug.

A person struck by lightning is more or less stunned and deprived of consciousness for a time, often, no doubt, by mere fright, in which case the effect is transient; but sometimes in consequence of a shock given to the brain, in which latter case there is a certain amount of paralysis of motion and sensation. In a case recorded by Boudin in his Géographie Médicale, 1857, a gentleman who had been struck by lightning remained for an hour and a quarter apparently devoid of any indication of life; and the paralysis, which usually affects the lower limbs, may last for many months. Mr. Holmes, in his article on "Accidents from Lightning," in his System of Surgery, gives the following list of other affections caused by lightning: "Burns, more or less extensive; eruptions of erythema or of urticaria, which are said by one author to have reappeared with each succeeding thunder-storm; loss of hair over parts or the whole of the body; wounds; hemorrhage from the mouth, nose, or ears; loss of sight, smell, speech, hearing, and taste; or, in rare cases, exaltation of these special senses; cataract, imbecility, abortion." Another curious effect of lightning is that described under the head of LIGHTNINGPRINTS. In reference to the occasional loss of hair, M. Boudin (op. cit.) relates that the capt. of a French frigate, who was struck by lightning on board his ship, could not shave himself on the following day, the razor not cutting but tearing out his hair. From that day the beard disappeared, and the hair of the scalp, eyebrows, etc., gradually fell off, leaving him entirely bald. The nails of the fingers also scaled away. Sir B. Brodie tells a curious story of two bullocks, pied white and red, which were struck in different storms; in both cases the white hairs were consumed, while the red ones escaped. As a general rule, it seems that persons not killed on the spot usually recover. The burns present every degree of intensity; in some (probably exaggerated) cases we hear of men and animals being reduced to ashes, while in ordinary cases they vary from deep burns, difficult in healing, to mere vesications: they must be treated in the ordinary method. It was believed until recently that the burns are caused by the ignition of the clothes; it appears, however, from various cases collected by Dr. Taylor (Med. Jurisp., 1865, p. 737), that burns, at all events in some cases, are the direct result of the electricity. One case is so singular that we shall give a few details regarding it. Mr. Fisher of Dudley was called in to see a man who 16 hours previously had been struck by lightning while milking a cow. The cow was killed on the spot, and the man was much injured, there being a severe burn extending from his right hip to his shoulder, and covering a large portion of the front and side of the body. His mind was wandering; there were symptoms of inflammatory fever, and he was confined to bed for 17 days, at the end of which time the healing process was not complete. On examining his dress, it was found that the right sleeve of his shirt was burned to shreds, but there was no material burning of any other part of his dress. Hence it is obvious that the dress may be burned without the surface of the body being simultaneously injured; and, further, that a serious burn may be produced on the body although the clothes covering the part may have escaped combustion.

The appearances after death vary extremely. The body sometimes retains the position which it occupied when struck, while in other cases it may be dashed to a considerable distance. The clothes are often burned or torn, and have a peculiar singed smell; and metallic substances about the person present signs of fusion, while such as are composed of steel become magnetic. There are generally marks of contusion or

Lightning.

laceration, or, if they are absent, extreme ecchymosis (q.v.) at the spot where the current entered or emerged. In addition to wounds and burns, fractures have also been

noticed.

The treatment must be directed to the special symptoms, which are liable to great variations. Sir B. Brodie's advice is as follows: "Expose the body to a moderate warmth, so as to prevent the loss of animal heat to which it is always liable when the functions of the brain are suspended or impaired, and inflate the lungs, so as to imitate natural respiration as nearly as possible." These means should be fully tried, as respiratory action has been restored after more than an hour's suspension. Mr. Holmes additionally recommends cold affusion, stimulating enemata, and stimulants by the mouth; and recovery (he states) is apparently hastened by the administration of tonics, especially quinine, and gentle action on the skin by means of baths.

LIGHTNING-CONDUCTOR (Fr. paratonnerre, Ger. Blitzableiter). The principle of the lightning conductor is that electricity, of two conducting passages, selects the better; and that when it has got a sufficient conducting passage, it is disarmed of all destructive energy. If a person holds his hand near the prime conductor of a powerful electric machine in action, he receives long forked stinging sparks, each of which causes a very sensible convulsion in his frame. But if he holds in his hand a ball, connected with the ground by a wire or chain, the above sensation is scarcely, if at all, felt as each spark occurs, for the electricity, now having the ball and wire passage to the ground, prefers it to the less conducting body. If, instead of a ball, a pointed rod were used, no sparks would pass, and no sensation whatever would be felt. The point silently discharges the prime conductor, and does not allow the electricity to accumulate in it so as to produce a spark; and the quantity passing at a time, even supposing the rod disconnected with the ground, is not sufficient to affect the nerves. If for the prime conductor of the machine we substitute the thunder-clouds; for the body, a building; for the convulsive sensation, as the evidence of electric power, heating and other destructive effects; for the ball, or rod, and wire, the lightning-conductor, we have the same conditions exhibited on a larger natural scale. It is easier, however, to protect a building from the attacks of lightning than the body from the electric spark, as the rod in the one case is a much better conductor, compared with the building, than it is compared with the body, and, in consequence, more easily diverts the electricity into it.

The lightning-conductor consists of three parts: the rod, or part overtopping the building; the conductor, or part connecting the rod with the ground; and the part in the ground. The rod is made of a pyramidal or conical form (the latter being preferable), from 8 to 30 ft. in height, securely fixed to the roof or highest part of the building. Gay-Lussac proposes that this rod should consist, for the greater part of its length below, of iron; that it should then be surmounted by a short sharp cone of brass; and that it should finally end in a fine platinum needle, the whole being riveted or soldered together, so as to render perfect the conducting connection of the parts. The difficulty of constructing such a rod has led generally to the adoption of simple rods of iron or copper, whose points are gilt, to keep them from becoming blunt by oxidation. It is of the utmost importance that the upper extremity of the rod should end in a sharp point, because the sharper the point the more is the electrical action of the conductor limited to the point and diverted from the rest of the conductor. There is thus less danger of the electricity sparking from the conductor at the side of the building into the building itself. Were the quantity of the electricity of the clouds not so enormous, the pointed rod would prevent a lightning-discharge altogether; but even as it is, the violence of the lightning-discharge is considerably lessened by the silent discharging power of the point previously taking place. According to Eisenlohr, a conical rod, 8 ft. in height, ought to have a diameter at its base of 13.3 lines, and one of 30 ft. a diameter of 26.6 lines.

The part of the lightning conductor forming the connection between the rod and the ground is generally a prismatic or cylindrical rod of iron (the latter being preferable), or a strap of copper; sometimes a rope of iron or copper wire is used. Iron wire improves as a conductor when electric currents pass through it; copper wire, in the same circumstances, becomes brittle. An iron rope is much better, therefore, for conducting than a copper one. Galvanized iron is, of all materials, the best for conductors. The conducting-rod ought to be properly connected with the conical rod either by riveting or soldering or both. Here, as at every point of juncture, the utmost care must be taken that there is no break in the conduction. The conducting-rod is led along the roof and down the outside of the walls, and is kept in its position by holdfasts fixed in the building. There must be no sharp turns in it, but each bend must be made as round as possible. Considerable discussion has arisen as to the proper thickness for the conducting-rod. If it were too small it would only conduct part of the electricity, and leave the building to conduct the rest, and it might be melted by the electricity endeavoring to force a passage through it as an insufficient conductor. The Paris commission, which sat in 1823. gave the minimum section of an iron conductor as a square of 15 millimeters (about three-fifths of an inch) in side, and this they considered quite sufficient in all circumstances. A rod of copper would need to be only two-fifths of this, as copper conducts electricity about six times more readily than iron. This calculation is very generally followed in practice. In leading the conductor along the building it

Lightning. should be kept as much apart as possible from masses of conducting matter about the building, such as iron beams, machinery, etc. These may form a broken chain of conductors communicating with the ground, and divert a portion of the electricity from the lightning-conductor. If such took place, then at each interruption electricity would pass in a visible and dangerous way, and the efficacy of the conductor would be lost. If the conductor cannot be properly insulated from these masses of metal, the necessary security is got by putting them in connection with the conductor, so as to form a part of it. Water-runs, leaden roofs, and the like, must, for this reason, all be placed in conducting connection with the conductor.

The portion of the lightning-conductor which is placed in the ground is no less worthy of attention than the other two. Should the lower part of the conductor end in dry earth, it is worse than useless, for when the lightning, attracted by the prominence and point of the upper rod, strikes it, it finds, in all likelihood, no passage through the unconducting dry earth, and, in consequence, strikes off to a part of the ground where it may easily disperse itself and be lost. Wherever it is practicable, a lightning-conductor should end in a well or large body of water. Water is a good conductor, and having various ramifications in the soil, offers the best facility to the electricity to become dispersed and harmless in the ground. The rod on reaching the ground should be let down a foot and a half, or 2 ft., into the soil, and then turned away at right angles to the wall from the building in a horizontal drain filled with charcoal, for about from 12 to 16 ft., and then turned into the well so far that its termination is little likely to be left dry. Where a well cannot be made, a hole 6 in. wide (wider, if possible) should be bored, from 9 to 16 ft., the rod placed in the middle of it, and the intervening space closely packed with freshly heated charcoal. The charcoal serves the double purpose of keeping the iron from rusting, and of leading away the electricity from the rod into the ground.

Lightning-conductors, when constructed with care, have been proved beyond a doubt to be a sufficient protection from the ravages of lightning. The circle within which a lightning-conductor is found to be efficacious is very limited. Its radius is generally assumed to be twice the height of the rod. On large buildings, it is therefore necessary to have several rods, one on each prominent part of the building, all being connected so as to form one conducting system. In ships, a rod is placed on every mast, and their connection with the sea is established by strips of copper inlaid in the masts, and attached below to the metal of or about the keel.

LIGHTNING-PRINTS are appearances sometimes found on the skin or clothing of men or animals that are either struck by lightning, or are in the vicinity of the stroke, and currently believed to be photographic representations of surrounding objects or scenery. The existence of such prints appears, from a theoretical point of view, highly improbable, as the essential conditions of forming a photographic image are wanting; still, several apparently well-authenticated instances have been recorded, which have led scientific authorities to give at least partial credence to them. One or two instances may serve to give a general idea of what are meant by lightning-prints. At Candelaria (Cuba), in 1828, a young man was struck dead by lightning near a house, on one of the windows of which was nailed a horse-shoe; and the image of the horse-shoe was said to be distinctly printed upon the neck of the young man beneath the right ear. On Nov. 14, 1830, lightning struck the château of Benatonnière, in La Vendée; at the time, a lady happened to be seated on a chair in the saloon, and on the back of her dress were printed minutely the ornaments on the back of the chair. In Sept., 1857, a peasant-girl, while herding a cow in the department of Seine-et-Marne, was overtaken by a thunder-storm. She took refuge under a tree; and the tree, the cow, and herself were struck with lightning. The cow was killed, but she recovered, and on loosening her dress for the sake of respiring freely, she saw a picture of the cow upon her breast. These anecdotes are typical of a great mass of others. They tell of metallic objects printed on the skin; of clothes, while being worn, receiving impressions of neighboring objects; or of the skin being pictured with surrounding scenery or objects, during thunder-storms. One object very generally spoken of as being printed is a neighboring tree. This may be accounted for by supposing that the lightning-discharge has taken place on the skin in the form of the electric brush (see ELECTRICITY), which has the strongest possible resemblance to a tree, and that this, being in some way or other imprinted on the skin, has led observers to confound it with a neighboring tree. Of other prints, it would be difficult to give a satisfactory account. However, observers have done something in imitation of them. It has been shown, for instance, by German observers, that when a coin is placed on glass, and a stream of sparks poured on it from a powerful electrical machine, on the glass being breathed upon, after its removal, a distinct image of the coin is traced out by the dew of the breath. Mr. Tomlinson, by interposing a pane of glass between the knob of a charged Leyden jar and that of the discharging-tongs, obtained a perfect breath-figure of the discharge on each side of the glass, which bore the most striking resemblance to a trec. With all due allowance for the probable printing-power of lightning, the accounts given of it, in most cases, bear the stamp of exaggeration; and such of them as have been inquired into have been found to dwindle to a very small residuum of fact, in which there remained little that was wonderful.

Ligulate.

LIGHTS, USE OF, IN PUBLIC WORSHIP, a practice which prevailed in the Jewish (Exodus xxv. 31-39) and in most of the ancient religions, and which is retained both in the Roman and in the oriental churches. The use of lights in the night-services, and in subterranean churches, such as those of the early Christians in the catacombs, is of course easily intelligible; but the practice, as bearing also a symbolical allusion to the "Light of the world" and to the "Light of faith" was not confined to occasions of necessity, but appears to have been from an early time an accompaniment of Christian worship, especially in connection with the sacraments of baptism and the eucharist. The time of the service in which lights are used has varied very much in different ages. St. Jerome speaks of it only during the reading of the gospel; Amalarius, from the beginning of the mass till the end of the gospel; Isidore of Seville, from the gospel to the end of the canon; and eventually it was extended to the entire time of the mass. In other services, also, lights have been used from an early period. Lighted tapers were placed in the hand of the newly-baptized, which St. Gregory Nazianzen interprets as emblems of future glory. Indeed, in the Roman Catholic church, the most profuse use of lights is reserved for the services connected with that sacrament. The usage of blessing the paschal light is described elsewhere. See HOLY WEEK. The material used for lights in churches is either oil or wax, the latter in penitential time and in services for the dead being of a yellow color. In the Anglican church, candlesticks and, in some instances, candles themselves are retained in many churches on the communion table, but they are not lighted. The retention of them is greatly favored by the "high church" party, and much disapproved by the "low church" or "evangelical" party. În the Presbyterian and Independent churches of Britain, America, etc., the symbolical use of lights and candlesticks is rejected as superstitious.

LIGNE, CHARLES JOSEPH, Prince de, 1735-1814; b. in Brussels, and descended from a wealthy and powerful Belgian family; entered the Austrian army in 1752, where he served with distinction through the seven years' war. In the reign of Joseph II. he held high military and diplomatic positions, and was a great favorite in all the European courts. During the reign of Leopold he fell into disgrace, owing largely, no doubt, to his son's participation in the Belgian insurrection of 1790, after which event he was never again in the public service, but lived in retirement at Vienna, employing himself in literary pursuits. Of his miscellaneous works in 34 volumes, which appeared in 1795-1811, Malte Brun has given selections in 2 volumes. His memoirs and letters have considerable historic value.

LIG NINE (derived from the Latin word lignum, wood) is the incrusting matter contained within the cellular tissue, which gives hardness to wood. Like cellulose, of which the cellular tissue is composed, it is insoluble in water, alcohol, ether, and dilute acids, and its chief chemical characteristic is, that it is more readily soluble in alkaline liquids than cellulose. Its exact composition is uncertain, but it is known to consist of carbon, hydrogen, and oxygen, and to differ in its composition from cellulose in containing a greater percentage of hydrogen than is necessary to form water with its oxygen. When submitted to destructive distillation, it yields acetic acid; and that it is the source of the pyroligneous acid (which is merely crude acetic acid) obtained by the destructive distillation of wood, is proved by the fact that the hardest woods (those, namely, which contain the greatest proportion of lignine) yield the largest amount of acid. Lignine is identical with the matière incrustante of Payen and other French botanists.

LIGNITE, fossil wood imperfectly mineralized, and retaining its original form and structure much more completely than the truly mineral coals, and therefore not improperly described as intermediate between peat and coal. Brown coal, surturbrand, and jet are generally regarded as varieties of lignite. The fossil plants of lignite are always terrestrial; palms and coniferous trees are amongst them. Remains of terrestrial mammalia are also found in it.

LIGNITE (ante), named from lignum, wood, a kind of coal, resembling, probably the condition of hard coal when in a state of transition or process of manufacture. It has no definite chemical composition. Some beds present a decidedly ligneous structure in the upper layers, and a true coal character below. When wood is buried in water or earth, it decomposes by the slow process of oxidation, or eremacausis, with the formation of carbureted hydrogen, carbonic acid, carbonic oxide, water, petroleum, etc., after a time leaving a denser, darker substance. After a long time it becomes black and exhibits a pitchy, somewhat conchoidal fracture. It is then lignite. This kind of coal is chiefly found in the cretaceous and tertiary formations, and in some localities forms immense beds, equal, perhaps, in extent to the beds of the carboniferous period. Lignite occupies an intermediate position between peat and hard and bituminous coal, and in favorable conditions in the process of ages peat will become lignite, and the latter will be converted into bituminous coal or anthracite. It is probable that most of the coal in China and India is more or less lignitic in its nature, as is the case of that of western America. Lignite is found also in Greenland and arctic America, and also in Central and South America. In Europe lignites have been mined for a long time, and are used not only for heating dwellings and other domestic purposes, but for generating steam in locomotives and furnaces. The following