MODERN EXPLOSIVES.

Otago Daily Times, Issue 19271, 8 September 1924, Page 8

MODERN EXPLOSIVES.

TWO CLASSIFICATIONS. An interesting review of the application of modern liigh explosives was given in a lecture delivered by Captain \Y. H. Kev-Jones at a recent meeting of the Auckland Officers Club. ..... . . ‘.‘Explosives may be classified into two groups, high explosives and low explosives,” said the lecturer. Low explosives are dispersive m their effect, and produce their effect by rapid combustion and production of a large volume of gas. They are used as the propellents ot projectiles, such as nfle bullets and shells, llso for demolition work where a dispersal effect is required. The most commonly known low are black powder cordite, balistite, E.C. Schultz, and Hteh explosives produce their effect by detonation, that is, by instantaneously disintegration into gases. fheir effect is shattering, owing to the fact that if applied to solids, they instantaneously produce terrific pressure and shatter the solids to pieces. H a properly-tamped charge of black powder was applied to a steel girder lying on the ground and fired it would move the steel girder as a whole whereas if a high explosive, say gun-cotton, were applied in the same way its effect would be to cut the steel girder to two, hardlv moving the girder at al and at the break, a portion of the steel girder would be shattered into small nieces The most commonly known high explosives are nitro-glycenne gun-cotton, dynamite, blasting gelatine, gelatine dynamite nilro-benzine, trinitro-toluol, known as T.N.T., aminol, and the various fulmlThese two broad classes of explosives may he again divided each into two subclass low explosives that are low explosives under all conditions, and those, such as cordite and the other nitro low explosives, that will detonate if they get a sufficient shock. Then there are the hteh explosives that require a fair amount oUshock to detonate, and those that are very sensitive. Sensitive high explosives arc nitre-glycerine and the fulminates. The lecturer demonstrated how sensitive a high explosive can be by causing a small portion of nitro-iodide to detonate with a sharp report by merely touching it with the tip of a feather. He then described the various explosives mentioned above, with reference to their military value, and outlined the methods of firing by electricity.