Dynamite. (From the Cornhill Magazine.)

Waikato Times, Volume XXIV, Issue 2000, 2 May 1885, Page 2 (Supplement)

Dynamite. (From the Cornhill Magazine.)

(CONTINUKD.) The destructive power of dynamite, which, contrary to common opinion, does not act downward!, bat equally in all directions, and with the greatest violence where there is the greatest resistance, has been greatly exaggerated. Mr. Moßoberts, the superintendent of Mr. Nobel's Scotch factories, hat published an estimate of its capabilities, which at a time of some public alarm like the present cannot be too often repeated and too widely known. A ton of dynamite equals 45,675 foot-tons, whioh in plainer language meam that if a ton of dynamite were scientifically confined and fired under a weight of 15,675 tons it would raise it one foot. A ton of nitro-glycerine, similarly exploded, will exert a power of 04,452 foot-tone, and a ton of blasting gela tine, of 71,050 foot-tons ; gelatine, therefore, confined aod fired under a building of 71,050 toni, * presenting in building stone ninetysix let! on the side, would only raise it one foot. And this it will not do unless it is confined, or at least with nothing like the same effect. Bore a bole under Nelson's monument and fill it with dynamite cartridges, especially if tbe operation be in experienced hands ; leave a box-full at the base, and the damage is • chipped stone, a few broken windowi, and a cabman blown off his box. Nor

are the broken windows, after all, a necessity; for while the explosive power of dynamite is intensely looal, its aerial disturbance, compared with that of gunpowder, is very small. The explosive power of dynamite is in inverse ratio of the cube of the distance, or, in more popular language, if the power exercised on the spot be represented by 1,000,000, the same power at the distance of a hundred feet dwindles down to 1. Mr. M'Hobertß tells us he has often exploded a pound of dynamite hung at the end of six feet of string from a fishing-rod, held in the hand without the smallest danger or inoonvenienoe^and on one occasion witnessed the explosion of over a ton of nitro glycerine from a distance of only sixty yards. It was buried about ten feet below the Burfaoe of the ground, whioh was of sand and covered with water, yet, beyond the breakage of windows and the busting of a few doors in the surrounding building*, there was no damage done. " A little sand was thrown over me," writes Mr. M'Roberts, " but I received no personal injury." Dynamite, then, wWoh has from five to seven iimes the explosive power of gunpowder, is comparatively trifling in its effeots at even short distances. The dynamitard, with all bis daring and cunning, has, after all, succeeded in doing us no more damage than gas has often done before. It would be better for him, if he desires to continue the warfare, to return to his ancient ally gunpowder, which above ground is a mucn more noisy and demoralising agent. In the explosion at the Local Government Board of March, 1883, when 27 lbs. of ordinary dynamite was the medium employed, there was neither destruction of life nor injury of limb, and the damage to the building was covered by about £150. At Sc. James's Square and Scotland Yard, on the night of May 30, beyond a few out faces and broken windows, no harm was done. But at Clerkenwell in December, 1867, when 50 lbs. of gunpowder were exploded against the prison wall, there were, according to the official report, six killed outright, six who died subsequently, five in addition who owed their deaths to the same cause, forty mothers prematurely confined and twenty of their babies born dead, one hundred and twenty wounded, and fifteen permanently injured by the loss of ejes, legs, or arms, and tho damage to property and person was estimated at £20,000. In our military service, dynamite has never yet been used. As a projectile agent it has no value whatever, for so instantaneous is its action that in a gun it would burst the breech before starting the ball, and at present no receptacle has been discovered strong enough to resist its action when confined. Its only utUity would lie in its power of destroying palisades, walls, or bridges ; for mines, countermines, torpedoes, and perhaps for some form of hollow piojeotile. But for these purposes gun-cotton is infinitely more serviceable, since in its most recent compressed shape it is absolutely safe in fire and under fire (which dynamite certainly is not; it is invariably detonated when etruok by a bullet passing through the side of the box) ; ie ii more convenient to carry, and pleasanter to handle ; there is no exudation, nor is it affected by wet, its detonating power in a wet state being even increased. Dynamite, then, strange and terrible as is its power, is almost entirely limited to the usages of commerce, and, unlike gunpowder, which for three hundred years flourished in war before its services were appreciated by industry, is readier to the hand of the miner than the soldisr. Bat the services of dynamite in civil engineering, and the economies it has effected in the two great commercial departments of time and money, can never be exaggerated. It is oalcalated that in time dynamite saves between 40 and 70 per cent., and in money between 20 and 40. Railways are now finished a year or two earlier than they used to be, and from fifty to seventy thousand miners are yearly saved from the dangers and diseases of tunnelling and blasting, since in the eoonomy of labor fewer are required. The Mont Cenis tunnel, where the work was at first entirely carried out by powder, took thirteen years and five months to complete ; the St. Gothard, considerably longer, where the nitro-glycerine oompounds only were employed, seven years and six months. In the first, the work lying through the soft rock, the cost has bean estimated at about £300 per metre ; in the second, at £160, through granite and gneiss. Gunpowder is a oleaving and displacing agent, dynamite a rending and a shattering, and for each there is a sphere of usefulness. For slate and coal dynamite is too powerful, bat for hard rook and pit-sinking, for the removal of subaqueous obstructions, wrecks, and submerged rocks, where materials of great rigidity and strength have to be operated upon, there is nothing that can effect the same economy in time, labor., and material. At Hell Gate, in the East River of New York, three acres of reef rook, lying 26 feet below mean low-water level, were, after four years and four months' work of perforation into chambers and drill-holes, blown up and the passage cleared. The charges were fired by electricity, and in the operation the discovery was for the first time applied that detonation may be transmitted from one mass of an explosive oompound to others through intervening air spaces. In the ordinary work of blasting, charge-holea are drilled, and into them are tightly fitted with a wooden rammer a sufficient number of dynamite cartridges. At the top is fixed the primer, a smaller cartridge, into whioh is placed the long detonator-cap of fulminate of mercury, closely fitted with a fuse. Dynamite has the advantage over other more powerful explosives that owing to its plasticity it can be moulded into the bore-hole, and so fits tightly. Gun-cotton is rigid, and nitro-glycerine in its pure state ia apt to escape through the fissures and be dangerously wasted. Numberless aooidents have ooourred through lightning, in boring, on some of the old escaped nitro-glyoerine, which, on being struck, invariably explodes. But, after all, it is not in its relations to blasting and tunnelling that the publio mind feels interest in dynamite, so muoh as in the part it has of late years been playing in outrage, and the almost terrific importance it has assumed in the estimation of many as a murderous instrument of so-oalled politioal warfare. The recently detected correspondence in Birmingham, with its many delicate allusions to the cough mixture, and the latest proposals to drop the explosive on us from a balloon, like ballast from a sand-bag, bring into undue prominence its dangerous side, and already begin to do muoh towards restricting the trade in an article of incalculable utility. Already the chief of Mr. Nobel's factories in Switzerland, at Istleten, near Fluelen, finds itself in some difficulties, owing to the restrictions placed by the Swiss Government in'the way of the explosive leaving the country. Here so much care is exercised by manufacturers and agents, that it is exceedingly improbable dynamite will ever be purchased from them for other than legitimate purposes. It lies within the experienoe of most who have dealings in the explosive to be occasionally visited by morose personages in soft hats, who come to buy a few pounds, and who, in reply to the question what it is wanted for, not uncommonly answer with an oath that that is no business of anybody but the purchaser. It may be a gentlemanly individual in a frock-coat, with an engaging manner, and a park and a few old trees to uproot that spoil the view from his diningroom window ; or a German baker, who, in some obicure Teutonic way, has need of it in connection with his busines; or a pallid young man who is going out mining to South Africa : to all the answer is the same — that they may blow their heads off with it if they please, but that until references of position and respectability are given, they will not get so muoh as will lie on the edge of a knife. The result is that in no oase of outrage in this conntry has the dynamite employed been traced to a licensed manufacturer or agent of Great Britain. It is, as a rule, of American manufacture, and hails from the Atlas Works. Tho dynamitard may make it himself in a back bed- room, if he pleases ; but since the Explosive Substances Act of last year, by so doing he lays himself open to penal servitude for fourteen years, and the burden of proof,

that the making, or even the possession, of any explosive substance for a lawful purpose, lies on the person «o making or possessing it. The exaggerated destructive power of dynamite we have already referred to, from which we expect it to be clear, as Mr. Roberts pays, that " the scoundrels who attempt to destroy public buildings are powerless to do much harm by their operations. They cannot by any means at their disposal lay a whole city in ruins — nor even & street. They may injure special buildings, and that ia the most they can do." And as a further consolation, it may be noticed that the dynamite employed for these purposes is, in the majority of ca<*es, of the kind known as lignin-dynamite, a wholly unlicensed explosive, composed of sawdust and nitroglycerine, and in its effeota considerably weaker chan that in common use. The explosions in Glasgow, and gome of those in London, wore chiefly distinguished for their childishness, their one redeeming point being the ingenuity with whioh in one or two oases the old detonation system of the Coaatgnard port fires vai combined in a novel form and applied to their trivial lignindynamite. There is one other aspect of dynamite that must not be passed over, and that an important one, the sanitary. In the days of gunpowder blasting in mines and the old system of ventilation, there was an excespive mortality among miners, due to a disease of the lungs known as miners' deoline. It was not the ordinary tubercular consumption, but a form developed in may other callings among workers in dusty places, and variously known as grinders' rot in Sheffield, stonemasons' decline, rag piokers' disease, and woolsorter's asthma. Since the introduction of dynamite and the common use of the nitroglycerine compounds, there has been a marked improvement in the miner's health ; for though, as we have said, the nitrous fumes of burnt dynamite are dangerous, with dynamite properly exploded nothing of the kind is experienced. Dynamite has been'put to strange uses, *nd among them for the slaughtering of cattle at Islington market in 1877 by fastening a small charge between the horns ; but never perhaps to one more strange or terrible than that adopted by & discharged clerk at Dunedin, in New Zealand, who, meeting in the streets his wife, from whom ha had been separated, under a pretence of salutation exploded a dynamite charge between their faces and blew both heads completely off. In conclusion, it is only ju3t, when reference hat been made to the poisonous character of nitro glycerine, to say something of its powers of healing. It has, like all other product! of beneficent nature, its time of calm and soothing, when its turbulence is at rest and its terrible energy exerted only for good. It is prescribed in minute doses for angina pectoris, according to the formula of Dr. William Murrell, who has written a book on the subject, and in man? nervouß and cerebral affections its paoifio effects are well known. It is rather, however, a specifio than, like its earliest ally, gunpowder, odcb was, a panacea ; for in the old days, when Tommy Atkins was depressed, despirited, or for any reason, military or civil, out of sorts, the most popular and efficaciom of his remedies was a charge of gunpowder in water.