Press enter after choosing selection

Atmospheric Electricity

Atmospheric Electricity image
Parent Issue
Public Domain
OCR Text

Wiu ffJiíMp jt(pi& Mr. Jíiditor : - Among the numerous elements that aro embraced in the problems of the bygeaist fevv are calculated to excite deeper interest than the subject of tliis article ; and although the sileut and unseen influenoe of this agent upon the well being, and the general sanitary conditions of the human race, is probably more important than those more vivid -and sublime manifestations that compel our attention when the electrical equilibrium of the surrounding elements has been greatly disturbed; yet in this brief article we propose to limit ourselves to the consideration of the latter as moro pertinent to our present purpose. Prominent among the data furnished ay recent researches stands the fact of the unequal distribution of nccidents to ife by lightning. Thus the records show that during the ürst half of the ourrent century there did not oceur a single death by lightning in the great city of Paris, and similar estimates made in the atter half of the last century prove that of the 750,000 deaths that occurred during 30 years in London, only two were caused by that agency. When these, and similar results obained froin the tables of mortality of other cities, are compared with the total number of deaths from this cause, and with the fact that 25 per cent of all ïappen under trees, it seems fair to conclude that it selecta its victims moro 'rcquently from the country than from cities Kiniilar in its mode of operation, alhougli less obvious as a causo of the unequal distribution, is the peculiar 'eological and hydrological structure of earth in different localities, as indieated )y soine of the most eminent Physicists; ïence, when the soil is arid and contains ut a small cjuantity of vegetable matter, and is underlaid by thick masses of dry and, lime, or granite, it enjoys an immunity from accidents, because it is not a conductor of electricity, and all human tructures erected in such localities are generally favored. But, if with these urface indications of immunity, there exists even at vory considerable depths, great beds of metáis, sheets of water, or only strata of earth rendered wet and conducting by springs, a discharge takes )lace when the charged thunder cloud lasses over it ; the lightning being at.racted by the conducting interior strata, and the dry crust proving no insurmountable obstaele, involves in destruction all intervening structures, whether composed of wood or stone. In France where the statistios have jeen most carefully gathered there seems -o be only an average of 72 fatal acci Jents from this cause per annum ; but the number of those who have suffered nore or less severely is considerable rreater, the estímate varying from the oroportion of 2 to 1, to 5 to 1, in different countries. In all countries in ivhich statisties have been collected, it ïppears, also, that men are much more 'requently injured than women, but whether from greater exposure in the apen fields or from other causes the data vet furnished do appear to be sufB cient satisfactorily to determine. Tbe 'ollowing statement, given upon the high authority of tho late Mr. Arago, is of great interest as tending to show great differences in degree of liability among individuals apparently alike in physical eondition. " In two conditions altogether alike," gays the eminent Physicist, '' one man by the nature of his constitution runs more danger than another. There exist persons who arrest abruptly the communication of electricity, and do not feel the shock even when they occupy the seoond place in the file. These persons by exception are uot conductora of tho electrio fluid, exceptionally then we must rank them among non-conducting bodies whicli liglitning respects, or which at least it raroly strikes. Differences so marked cannot exist without there being at the samo time shades of difference but every degree of conductibility during a storm corresponds to a certain mcasure of danger, Tlie man who is as conductory as metal will be as often struuk as metal; the man who interrupts tho oommunication in the chain will scarce have more to fear than if he were glass or resin. Thus in the phenomona of thunder all does not dopend upon the place a man oocupies; the physical constitution of a man plays also a certain part." The oharacter of the surface, also, whether plain or brokon, hilly or mountainous, exevoises a marked influence in the frequency of these accidenta, heneo a greater number of oases are reported aa having occarred in the broken and mountainous than in the naore level, or but slightly undulating portions of a state or country. Statistics also show conclusively the protection afforded by nonconductive bodies as tenements of wood, etc, as out of 53 persons killed by lightning whose position was praoisoly noted, only 10 wero struck in the inside of a house or barn, and 43 in the fields or woods, a proportion of tbo latter probably considerably exeeeding the numerical proportion of those ia the open air, or under shelter, during the passage of storms ; of the 34 killed in the fields during the same year, 15 had sought shelter under trees. The frequency of these accidents is varied unquestionably most by the seasons, the climates and the period of the day. In this country as in France, statistics show that the máximum occurs in the months of June, July and August, and of the different periods of the day the proportion of day and night is as 7 to 1, the maximum beiog betwecn the hours of 3 P. M., and 7 P. M., the minimum betwecn 11 P. M. and 3 A. M. A recent writer thus describes the variety and even contrariety of effects produced on the human organism. "At one time the individual is killed at once on the spot, the dead body romaining on horseback, or erect ; at another time we see the man killed thrown to a distance. Sometimes the lightning undresses its victims, destroys their clothes and respects the body ; f ometimes on the contrary it burns the body and leaves the clothes untouehed. Here the destruction goes to a frightful extent, with rupturo of the heart and orushing of the bones, there the most oareful examination re sults in a negative autopsy. Here you lave flaccidity of the members,softenina of the bones, collapse of the lungs and fluidity of the blood ; their distensión of the lungs, coagulated blood, and rigidity of the members with locked-jaw. Sometimes the bodies seem to brave ;he laws of decomposition ; sometimes again, the most rapid and horrible putre'action immediately seizes the corpse. - [n fine lightning whieh crushes a tree, and even stone work, appears to produce with difficulty mutilations in man, with separation of parts of the body." Mueh more might be added to this graphic sketch of the varied effects of this ngent on the human organisms, but it is feared the article has aljeady extended beyond the limits of the patience of your ders.


Old News
Michigan Argus