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lislied black powder manufacturers, who believed that in “shooting” oil wells, and even here “solid nitroglycerine,“ nothing could suppliint the explosive that had been in general a higli-grade blasting gelatin, seems to be gradually taking use for some six hundred years. Indeed, only a few years it,s place. The so-called gelatin dynamites, in which blasting carlier one of the promiuent powder men of his time had gelatin is mixed with active dopes, have been in use since staled that it was only a matter of time how soon a man the eighties and are becoming strong competitors of straight would lose his liie who used these new explosives, which dynamites. They have the advantage of being waterhe considered vastly more dangerous than punmowder. resistant. The applicatiun of physical It was not until 1880 that t,he chemistry to the manufacture leading black powder comof explosives has brought panies joiiitly furnished capital ahout low-freezing dynamites. to build a dyiiamite plant. Nitroglycerol normally freezes Black powder had gradually a t 12.8” C., and dynamite become standardized through i n t,he frozen condition is the centuries with a coutent of dangerous and uncertain in its 75 per cent potassium nitrat.e action. Many accidents have (or India saltpeter), 15 per occurred i n handling and ceut charcoal, and 10 per cent p a r t i c u l a r l y in thawing it. sulfur. This was its composlEarly attempt8 were made to tiou a t the time of the Revoreduce the freezing point by lution and no cliaiige had been adding other substances, such made i n t h e next hundred as nitrated hydrocarbons and y e a r s , e x c e p t that sodium sugars. The use of nitrated nitrate or Chile sa1t.peter lied polymerized glycerol (diglybeen subvtitutcd in blasting cero1 or glycerol ether) has beeu powders for the more expeusive ~ ~ i o asuccessful t, iu this respect potassium salt. In military arid has made i t possible to powders the form oi the grain had been changed, foliowing p r o d u c e n o t only straight dyiamites but alsogelatin, amt h c classic cxperiu~eiits of General Rodman just before monia, and permissible dyuathe Civil War, so as to obtain iuitcs, which will not freeze mor e progressive burning even in the cold climate of the qualities which permitted the Northwest. use of higher charges and The coal-mining i n d u s t r v has been cursed jby gas a& consequently greater muzzle dust explosions ever since exvelocities. A further step iri this direction was the introplosives \\-ere used in mining. Giant Gates in Denver Mountain Park. where a Great Deal of Blasting Was Necessary to Put Through the Roact duction of the so-called brown The study of the causes of was start,ed these disant,ers p r i s m a t i c or cocoa powder ~ ~ .. ~ .......in. . . in the early eighties. This contained a mixture of sugar Europe in the early eighties and led to the conclusion that and brown or underburned charcoal in place of the black, the length and duration of the flame of the explosion of completely burned charcoal of the old gunpowder, and its the powder were among the most important factors. Chemsulfur content had been reduced to 3 oer cent.. Powder of istry showed the way to reduce both without materially this type was still in use in the cannon 0; our Army and Navy decreasing the effect of the powder. The permissible exploduring the Spanish War, although smokeless powder was sives of the present day are the result of this work and are so used in small arim. No further developments have taken successfully meeting the problem that the U. S. Bureau of place in this field except along mechanical lines. Machinery Mines states that they have no record of any such explosions has been perfected and safeguarded to an extent undreamed having been eaused by permissible esplosives. of fifty years ago. Lately it has been found that results Decrease in Cost approaching those of high explosives may be obtained with One of the outstanding features of the progress of t h e black blasting powder if its explosion is initiated by a detonating fuse of trinitrotoluene. explosives industry has been an enorrnous decrease in the Besides the No. 1 or kieselguhr dynamite, American fac- cost to the consumer. The first dynamite made in this tories in 1876 were also making dynamibes with active country was sold for $1.75 per p o n d By 1876 oompe“dopes”-i. e., they contained, instead of the inert kieselhad forced this down to about. th these figures present prices guhr which reduced the power of the explosive, mixtures of carbonaceous materials and saltpeter. While the original seem ridiculously low. This great decrease has been made idea may have been to circumvent Nobel’s patents, it was possible largely through a study of the chemistry of the soon recognized that these active dopes had many advan- nitration of glycerol, which resulted, among other things, tages, and that by appropriate formulation dynamites could in increasing the yield from about 180 pounds per 100 pounds be obtained ranging from the shattering effect of No. 1 of glycerol to the present figure of 233 to 235 per cent. This (1ynamit.e to the slow, heaving action of black blasting is about 97 per cent of the theoretical and about as high as powder. These “straight” dynamites have replaced kiesel- ean be obtained, taking into account the solubility of nitroguhr dynamite almost entirely. Nobel’s blasting gela- glycerol in the waste acids and wash waters. The use of tin, introduced in 1873, which is 8. stiff jelly produced by the stronger acids made available through the contact sulfuric addition of a small amount of soluble nitrocellulos acid process, the adoption of better ratios of sulfuric to glycerol, extended this eEect in the other directi nitric acid with a better water balance in the reaction mixan explosive that closely approached straight nitroglycerol. ture, the introduction of refrigeration in nitration which reToday nitroglycerol as such in the liquid form is used only duces the loss of glycerol through oxidation and other side. ~~~
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