It was in trying to make guns of a new strength that Sir Henry Bessemer entered the path which enabled him to make steel at little more cost than cast iron. It was in providing guns with explosives of new power that Alfred Nobel won both distinction and fortune. As in the case of Sir Henry Bessemer, his gifts have inured vastly more to the service of peace than of war. It is estimated that during the Civil War, 1861-65, more explosives were used in the United States by civil, railroad, mining and quarrying engineers than in the field of battle. Chief of these explosives was gunpowder; nitro-glycerine, though well known, had then little or no acceptance, for good reasons. How its defects were overcome is told by Mr. Henry de Mosenthal in an article on Alfred Nobel, in the Nineteenth Century Magazine, London, October, 1898. By the editor’s kind permission that article is here freely drawn upon. Nitro-glycerine, discovered by Sobrero in 1847, is made by treating glycerine with a mixture of nitric and sulphuric acids; it is poisonous, very sensitive to a shock, and most dangerous to handle. Being liquid it runs into the fissures of rock when poured into a bore-hole, and requires to be carefully confined that it may explode when ignited by means of a simple fuse. Nobel tried to overcome these deficiencies, first by mixing the liquid with gunpowder, and then by adding fluids which rendered it non-explosive, so that it could be safely transported, the added liquid being removed just before use; he also suggested confining it in a tube having the shape of a bore-hole, and firing it by means of a small gunpowder cartridge or primer. But all this did not avail, and accidents occurred so frequently that the use of the blasting oil was prohibited in Belgium, in Sweden, and later on in England. A vessel carrying some cases shipped from Hamburg and bound for Chili was blown up, and the event caused such a sensation that it seemed as if the use of nitro-glycerine would be prohibited the world over. In the meantime, however, Nobel had solved the problem of its safe use, and at the end of 1866 he had invented a compound, which he called dynamite, made by mixing the nitro-glycerine oil with porous absorbing material, thus converting it into a paste. Dynamite proved on experiment to be comparatively insensitive to a shock or a blow; it burnt when ignited, and could be properly exploded only by means of a powerful detonator fixed to the end of the fuse and inserted into the plastic explosive.