EXPLOSIVES. 



343 



our present knowledge is, that an explosion 

 arises from the transformation of the shock 

 into heat. The shock may be propagated from 

 particle to particle in an explosive, or from one 

 explosive body to another not in direct contact 

 with it. The latter of these processes has giv- 

 en rise to the so-called "synchronous vibratory 

 theory " of Sir Frederick A. Abel, of the Royal 

 Arsenal, Woolwich, England. This authority 

 claims that the originating cause of the detona- 

 tion of an explosive lies in the synchronism 

 between the vibrations produced by the body 

 that provokes the detonation and those that 

 the first body would produce in detonating, pre- 

 cisely as the string of a violin resounds at a dis- 

 tance in unison with another vibrating cord. 

 P. E. Berthelot, who is President of the Com- 

 mittee on Explosive Substances under the 

 French Government at Paris, has opposed the 

 foregoing theory, and maintains that the trans- 

 formations of mechanical energy into heat, and 

 the retransformation of this into mechanical 

 energy, are quite sufficient to explain the phe- 

 nomena. His own words are, that it depends 

 on the production of two orders of waves : one 

 series represents the explosive waves properly 

 so called, developed in the midst of the matter 

 that detonates, and consists of a continually 

 reproduced transformation of the chemical 

 actions into thermal and mechanical actions, 

 which transmits equally the sudden pressure 

 all around the center of the concussion to the 

 adjoining bodies, and, by a singular circum- 

 stance, to a new mass of explosive material. 

 This latter theory is in the line of the recent 

 investigations of that branch of chemistry 

 known as " thermo-cheraistry." 



Gunpowder, In the manufacture of gunpow- 

 der there is but little change. The introduc- 

 tion, here and there, of some mechanical im- 

 provement is the only important advance made. 

 The composition of the ordinary service powders 

 of most nations fluctuates about the following 

 numbers : 



Dr. H. Debus has recently presented the fol- 

 lowing theory before the Royal Society of 

 Great Britain : " The combustion of gunpow- 

 der consists of two distinct stages : a process 

 of oxidation, which is finished in a very short 

 time, occupying only a very small portion of a 

 second, and causing the explosion, and during 

 which potassium carbonate and sulphate, car- 

 bon dioxide, some carbon monoxide, and ni- 

 trogen are produced ; and a process of reduc- 

 tion, which succeeds the process of oxidation, 

 and requires a comparatively long time for its 

 completion. As the oxygen of potassium nitrate 



(saltpeter) is not sufficient to oxidize all the 

 carbon to carbon dioxide and all the sulphur to 

 sulphur trioxide, a portion of the carbon and 

 a portion of the sulphur are left free at the 

 end of the process of oxidation. The carbon 

 so left free reduces, during the second stage of 

 the combustion, potassium sulphate, and the 

 free sulphur decomposes potassium carbonate. 

 Hydrogen and marsh-gas, which are formed 

 by the action of heat upon charcoal, likewise 

 reduce potassium sulphate, and some hydrogen 

 combines with sulphur, forming hydrogen sul- 

 phide." Abel and others oppose this theory 

 as being based upon unwarranted assumptions. 

 It is too early as yet to consider its acceptance. 

 Among the many substitutes for gunpowder are 

 the following : 



Saxifragine is a mixture of charcoal and 

 barium nitrate with a small proportion of po- 

 tassium nitrate. Diorexine composed of po- 

 tassium nitrate, 50 parts ; sodium nitrate, 25 ; 

 sulphur, 12 ; and sawdust from hard wood, 13. 

 Petralite potassium nitrate, 64 parts ; impreg- 

 nated wood or charcoal, 30; crude antimony, 6. 

 Johnite potassium nitrate, V5 parts ; sulphur, 

 10; lignite, 10; sodium picrate, 3: potassium 

 chlorate, 2. Azotine sodium nitrate, 69'04 

 per cent. ; carbon, 15-23; sulphur, 11-43 : and 

 petroleum, 4'29. Carboazotine potassium ni- 

 trate, 61-04 per cent.; ferrous sulphate, 6'Y3 ; 

 soot, 24-65 ; and sulphur, 13-58. The class of 

 explosives usually considered under the title 

 Blasting-powders has been largely superseded 

 by the higher explosives. Certain improve- 

 ments in the way of electric blasting apparatus 

 have been devised, but their use is limited. 



Gun-cotton, discovered by Schonbein in 1846, 

 failed at first to become a commercial success 

 as a valuable explosive on account of its liabil- 

 ity to spontaneous explosion, its corroding resi- 

 dua, and its excessively violent and irregular 

 character. Official commissions in France, Ger- 

 many, England, United States, and Austria, re- 

 ported adversely as to its value. Von Lenk, of 

 Austria, improved the methods used in its 

 manufacture, but its present importance is due 

 principally to the investigations of Abel. The 

 compressed gun cotton devised by this chemist 

 finds extensive use for military and naval pur- 

 poses in many countries. 



Glyoxilin, invented by Abel, consists of a 

 gun-cotton pulp mixed with potassium nitrate 

 (saltpeter), converted into porous pellets, which 

 are saturated with nitro-grycerin, and after- 

 ward coated with varnish to protect them from 

 dampness. Atlas dynamite is similar to gly- 

 oxilin in composition. The addition of a small 

 quantity of paraffin renders it water-repellent. 

 The use of other forms of cellulose as absorb- 

 ents for nitro-glycerin are referred to under 

 dynamite. Tonite consists of finely divided or 

 macerated gun-cotton, mixed with about the 

 same weight of barium nitrate, made up into 

 candle-shaped cartridges. Standard tonite con- 

 sists of 52-5 parts of gun-cotton, and 47"5 parts 

 of barium nitrate ; but for special purposes and 



