MODERN EXPLOSIVES

New Zealand Times, Volume XXXIX, Issue 8857, 7 October 1914, Page 2

MODERN EXPLOSIVES

INTERESTING EXPERIMENTS LECTURE BY PROFESSOR EASTEKFIELD. Last night the lecture of Professor Basterfield on the subject of ‘War Lv' plosives/* organised by the \ictoria College Students’ Association, took place in the Grand Opera House, lent for the occasion by J. C- Williamson, Ltd. There was a fairly large audience, which included His Excellent/ the Governor. The lecture was illustrated by numerous experiments which in every case produced a most realistic explosion. The professor said that a high temperature and a diffusion .of gases were two features of explosions. . Detonations occurred when the explosion travelled at a fast rate—thousands ofeet per* second. Not only flame, hut light could produce an explosion. The experiment of burning magnesium wire in proximity to a mixture of chlorine resulted in an explosion.. .But the most common cause of explosions was concussion. Houses in ’ which nitroglycerine was made were separated from one another by earthworks to interrupt the pulse of the explosion. . Experiments with iodine of nitrogen, a few grains of which were placed in six adjacent heaps, illustrated this point. Dealing with war explosives proper, the professor explained the composition of gunpowder, which was • known to Roger Bacon in the thirteenth century. It had gone almost entirely out of use, said the lecturer, as a means of propelling projectiles. But before its disappearance it was used in the Brit mu army in the form of cakes, not powder. Nitre, obtained from nitrates, was a necessary ingredient of gunpowder, guncotton, and most other explosives, Most of the nitrates came from India, overseas, and Continental nations, especially Germany, had made strenuous efforts to obtain-supplies by chemiSal experiments. Th© French discovered a way of obtaining nitrates from sewage, and tho Germans had discovered a method of making nitrates -from the air in localities where electric power was cheaply obtainable. A German-owned nitrate factoryexisted in Norway, and the . product could be easily carried to Prussia. The professor calculated that iiIOOO a day went up the Wellington Gas Company s chimneys in the form of nitrates. Gun-cotton, continued the lecturer, cotton soaked in nitric acid, was for a long time used in guns, but sometimes it detonated instead of burning, and so burst the barrels, and sometimes exploded when" stored. Not cotton alone, but am y cellulose, such as New Zealand flax, would do for the basis of guticotton. Both this and nitro-giyccnne irei-e similar in nature. When these two explosives were incorporated and mixed with vaseline the result was a jelly called cordite, need all over the world ae a propellant. The professor then showed cross sections of the different kinds of, shell, including common shell and shrapnel. Lyddite (picric acid, made from carbolic acid, made in turn from coal tar) was used to pack ehells. Picric acid was used for a dye fifty years before its explosive properties were suspected. It exploded with great force, killed from shock all men within twentyflvo yards- of the explosion, and reduced a steel shell to metal dust. Lyddite, however, exploded when brought into contact with rust, and this was its groat disadvantage. To overcome this the inside of a shell was varnished, aiid another coal tar product wtis being tried to obtain a new exjplosive without this disadvantage. Fulminate of mercury, made from nitric acid, quicksilver and alcohol, was used fob making detonating caps. A detonator composed of this substance, containing IS grains, exploded with such force as to split a railwaysleeper when the experiment was triedAll modern explosives, said the professor in conclusion, were tho result of continuous experimenting in the chemical laboratories. Groat Britain was now spending jBfIO.OOO per annum on explosive experiments at Woolwich, and tho reproach that she depended on the research of other nations no longer existed.

Professor Easter field heartily thanked all those who contributed to make the lecture a success.