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DYNAMITE (Gr. S6eaµis, power)

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Originally appearing in Volume V08, Page 764 of the 1911 Encyclopedia Britannica.
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DYNAMITE (Gr. S6eaµis, See also:power) , the name given to several explosive preparations containing See also:nitroglycerin (q.v.) which are almost exclusively used for See also:blasting purposes. The first See also:practical application of nitroglycerin in this way was made by A. See also:Nobel in 1863. He soaked See also:gunpowder with the liquid and fired the See also:gun-See also:powder by an See also:ordinary fuse. Later he found that nitroglycerin could be detonated by the See also:explosion of several materials such as fulminate of See also:mercury, the use of which as a detonator he patented in 1867. In 1866-1867 he experimented with See also:charcoal and other substances, and found the infusorial See also:earth known as kieselguhr, which consists mainly of See also:silica (nearly 95%), eminently adapted to the purpose, as it was inert, non-combustible, and after a little See also:heating and preparation very porous, retaining a large amount of nitroglycerin as See also:water is held in a sponge, without very serious exudation on See also:standing. This kieselguhr dynamite is generally made by incorporating three parts of nitroglycerin with one See also:part of the dry earth, the See also:paste being then formed into cylindrical cartridges. This See also:work is done by See also:hand. Generally a small percentage of the kieselguhr is repiaced by a mixture containing See also:sodium and ammonium See also:carbonates, See also:talc and ochre. This product is known as dynamite No. 1.

Disabilities attaching to kieselguhr dynamite are that when placed in water the nitroglycerin is liable to be exuded or displaced, also that, like nitroglycerin itself, it freezes fairly easily and thawing the frozen cartridges is a dangerous operation. Other substances, e.g. See also:

kaolin, See also:tripoli, See also:magnesia See also:alba (See also:magnesium carbonate), alumina, See also:sugar, charcoal, some powdered salts and mixtures of sawdust and salts, have been shown to be absorbents more or less adapted to the purpose of making a dynamite. Charcoal from See also:cork is said to absorb about 90% of its See also:weight of nitroglycerin. With the See also:idea of obtaining greater safety, mixtures have been made of nitroglycerin with See also:wood fibre, charcoal and metallic nitrates._ Lithofracteur, for instance, consists of 5o% nitroglycerin and a mixture of prepared sawdust, kieselguhr and See also:barium nitrate. Carbonite contains 25 % of nitroglycerin, the See also:remainder being a mixture of wood-See also:meal and See also:alkali nitrates, with about 1% of See also:sulphur. Dualin, See also:atlas dynamite and potentite are other modifications. A convenient See also:form in, which nitroglycerin can be made up for blasting purposes, especially in wet ground, is the gelatinous material obtained by the See also:action of nitroglycerin, either alone or with the help of solvents, on See also:low-grade or soluble gun-cottons. It is known as blasting See also:gelatin, and was first made by Nobel by incorporating 6 or 7% of low nitrated See also:cellulose (See also:collodion See also:cotton or soluble gun-cotton) with slightly warmed nitroglycerin. The result is a transparent plastic material, of specific gravity 1.5 to 1.6, which may be kept under water for a See also:long See also:time without appreciable See also:change. It is less sensitive to detonation than ordinary dynamite, and although its explosion is slightly slower it is more powerful than dynamite and much See also:superior to the liquid nitroglycerin. Blasting gelatin also freezes and is sensitive to percussion in this See also:state. Camphor and other sub-stances have been added to blasting gelatin to render it more solid and less sensitive.

Some modifications of blasting gelatin, e.g. gelignite, contain wood-meal and such See also:

oxygen-containing salts as See also:potassium nitrate. Experience has conclusively shown that dynamites are more satisfactory, quicker, and more intense in action than liquid nitroglycerin. To prevent nitroglycerin and some of the forms of dynamite from freezing it has been proposed to add to them small quantities of either monochlor-dinitroglycerin or of a nitrated poly-See also:glycerin. The former is obtained by first acting upon glycerin with See also:hydrogen chloride to produce u-chlorhydrin or chlor-propylene glycol, C3H;02C1, which is then nitrated as in the See also:case of glycerin. The latter is obtained by heating glycerin for six or seven See also:hours to about 300° C., whereby water is split off in such manner that a diglycerin C,H11O5, for the most part, results. This on nitration in the usual manner gives a product C5HioN4013, which See also:burns and explodes in a similar manner to ordinary nitroglycerin, but is less sensitive and does not so easily freeze. The mono- and di-nitrates of glycerin have also been proposed as additions to ordinary nitroglycerin (q.v.) for the same purpose. (W. R. E.

End of Article: DYNAMITE (Gr. S6eaµis, power)

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