DYNAMITE, an explosive produced by the admixture of nitroglycerin with a siliceous infusorial earth known under the German name as kieselguhr. Nitro glycerin, which can be prepared in small quantities by dropping glycerine into a mixture of strong nitric and sulphuric acids, the temperature being kept as low as possible, was discovered by Sobrero in 1846, but it was not till nearly 20 years later that the experiments of Alfred Nobel, who combined it with the absor bent inert earth just mentioned, placed the new substance on a basis of practical and commercial importance.
Kieselguhr is the mineral remains of a species of algae; the stem consisted chief ly of silica, and when the organic por tions of the moss decayed, the tubular siliceous stem remained, retaining its shape. Beds of kieselguhr, underlying peat, are found in many countries•, the principal formations in Europe being in Great Britian (especially Aberdeen shire—that of Skye not being sufficiently absorbent), Germany, and Norway. The
raw kieselguhr, after calcination in a specially designed kiln to remove water and organic substance, is ground and sifted, and finally contains about 98 per cent. pure silica with traces of lime and iron.
Dynamite, which has a reddish-brown color, consists of 1 part of kieselguhr to 3 parts of nitroglycerin, and has a spe cific gravity varying from 1.59 to 1.65. Dynamite burns with a yellowish flame, and in small quantities without danger; but explodes with great violence when fired by a detonating fuse. Dynamite is much employed in breaking up boulders and the heavier metal castings, also in agricultural operations for removing the roots of trees.