But there is an increasing opaque dimness in the western horizon that steadily deepens in color. Fleece-like clouds rapidly increase in height and density, and a sheet of pale flame flashes from the midst and is gone. A glowing, crinkly line marks the edge of the cloud, and disappears.
Now swallows soar far up in the sky, the doves make wild, uncertain flights above the steeples, and the hoarse trumpet of the steamer again calls for recognition. At the west another bright line falls, zigzag, to a distant hill, revealed an instant, then lost in the shadow of the cloud. Soon there is a low, momentary rumble, and you are assured that the swift, delightful, dangerous shower, that cools the earth without interrupting our pleasures for dreary days, is approaching. No one whose dwelling is not better protected than most of those which bear the vain and flimsy decorations called "lightning-rods" can know whether his own house may not in a few moments receive a ruinous stroke, or that it may not be his lot to enter eternity with the first flash from that dark, towering mass of sulphurous hue that already casts its ominous shadow upon his face.
Timid persons should experience gladness rather than alarm at the sound of the thunder and the flash of the lightning, both being signals that personal danger is past for the time. Persons who have been struck and rendered insensible, but who have afterward recovered, had not seen or heard what hurt them. Unless we are acquainted with the locality, and know the points likely to receive the fiery bolt; if a disruptive discharge occurs near us there is no telling the spot of danger or of safety in open ground. A discharge from the front of the cloud may take a downward angle of forty-five degrees, and, passing over hill and forest, strike an insignificant knoll or a moist meadow half a mile in advance of the cloud. For myself, if overtaken in the country by a thunderstorm, I would seek the nearest and most convenient shelter from the rain and take my chance with the lightning.
Teams and the persons accompanying them appear to be peculiarly in danger during a thunderstorm. Caves, and even deep mines, afford no absolute safety, for the thunderbolt has been known to enter even these. Tall trees are more dangerous than low ones, but none of them appear capable of affording protection against this mysterious element. The people of different countries have regarded various kinds of trees as exempt from the electric stroke, but inquiry has always shown that every species has suffered in one locality or another. The beech, from some cause, has probably escaped more generally than any other tree of considerable size in northern latitudes. But it is the neighborhood of a good conductor, not a sheltering non-conductor, that affords safety. Some scientific men have advised a station of fifteen to forty feet from a tree, or such a position between several trees, but it has sometimes happened that such open spaces have received the bolt. In cities and villages, likewise, open spaces are not found to be places of safety.[5]
The question whether the small metallic articles usually carried about the person increase the danger is a matter of some concern. Many persons on the approach of a thunderstorm customarily relieve themselves of these things. Hair-pins, clasps and the metallic springs often used in the dresses of ladies are not, however, so easily got rid of. From the record of the effects of lightning upon the human body we reach the conclusion that metal is dangerous about the person only according to its position. Constantine mentions that during a thunderstorm a lady raised her arm to close a window, when a flash of lightning entered: her golden bracelet was entirely dissipated, but without the slightest injury to the wearer. A similar case is reported in the Edinburgh New Philosophical Journal for 1844. During a violent thunderstorm a fishing-boat belonging to Midyell, in the Shetland Islands, was struck by lightning. The discharge came down the mast (which it tore into shivers) and melted a watch in the pocket of a man who was sitting close by, without at all injuring him. He was not even aware of what had happened until, on taking out his watch, he found it fused into one mass. Instances might be cited where a portion of the shoe was carried away without serious injury to the wearer, and where knitting-needles, scissors and other household implements have been struck, sometimes conducting the current to the person with fatal effect.
During a thunderstorm in France in July, 1858, a peasant-woman, on her way home from the fields, was struck down by lightning. No wound was detected upon her person, but her hair was singed and a part of a silver comb melted. Here metal seems to have conducted the electricity to the body. On the other hand, the traveller Brydone relates a circumstance which happened to a lady who was regarding a thunderstorm from her window. At a flash of lightning her bonnet was reduced to ashes, nothing else about her being affected. Brydone supposes the electric current to have been attracted by the metallic wire which maintained the shape of her bonnet. Hence he proposes that either these wires be abandoned or in times of danger a metallic chain be attached to the bonnet, by which the charge might pass to the earth. Accordingly, we find that it became fashionable in France at that period to wear on the top of the bonnet an ornament of bright metal connecting with a small silver chain dropping down to the ground. At about the same time umbrellas were carried fitted with wires and chain for a similar purpose.
In July, 1819, lightning fell upon the prison of Biberach in Suabia, and there struck, in a common apartment, among twenty prisoners, one only—a condemned captain of brigands, who was chained about the waist. A similar arrangement of metal proved fatal in another case. On the 9th of October, 1836, on the coast of Italy, a young man was struck by lightning and killed. It was found that he wore a girdle containing gold coins. Undoubtedly, danger or safety depends on properly placing the conducting object. It may convey the current to the vital organs or it may ward off the stroke. Probably any line of metal parallel with the length of the body when upright would be in some degree a protection. The noted Dr. King once saw a military company receive a discharge of electricity from the clouds upon their bayonets, whence their muskets conducted it to the ground without harm or any painful shock. On the other hand, a battalion of French infantry, while marching between Mouzon and Stenay, June 2, 1849, was struck by lightning, and two men killed, while about two hundred were struck to the ground. Blood flowed from their mouths, ears and noses. This effect appears to have been the result of the concussion. Similar results sometimes follow from heavy discharges of artillery.
Uniform testimony goes to show that men in metallic armor have never been fatally injured by lightning. A complete suit of metallic armor embodies the principle of the well-known electrical cage of Faraday. This is simply a basket of wire network with its open side to the ground. If the wire is of proper size and the capacity sufficient, this cage is the most effectual protection possible, unless the walls be of solid iron.
If one places beside him a better direct conductor to the earth than his own body, he will not be fatally injured by the electric current, though, if it pass very near, he may be blinded by the glare or deafened by the noise—effects which are usually temporary. Equal safety for buildings may be similarly secured.
Glass being so well known as an excellent non-conductor, some have been led to suppose it effectual in warding off the disruptive stroke. Hence chambers or cases of glass have actually been made for the use of individuals who were apt to be overcome with terror during the prevalence of a thunderstorm. In this belief, also, the vane of Christ Church in Doncaster, England, was furnished with a glass ball; but the spire was afterward struck, causing great damage. Many also think they may sit beside a closed window in safety, but records of holes being melted in the glass and whole windows crumbled to powder by lightning are too numerous to admit of any reliance upon such a precaution.