*\ 
 
INDUSTRIAL CHEMISTRY 
 
 BEING A SERIES OF VOLUMES GIVING A 
 COMPREHENSIVE SURVEY OF 
 
 THE CHEMICAL INDUSTRIES 
 
 EDITED BY SAMUEL RIDEAL, D.Sc. LOND,, F.I.C. 
 
 FELLOW OF UNIVERSITY COLLEGE, LONDON 
 
 ASSISTED BY 
 
 JAMES A. AUDLEY, B.Sc., F.I.C. R. S. MORRELL, M.A., PH.D. 
 W. BACON, B.Sc., F.I.C., F.C.S. J. R. PARTINGTON, M.A., PH.D. 
 
 E.DE BARRY BARNETT, B.Sc.,A.I.C. ARTHUR E. PRATT, B.Sc.,Assoc.R.S.M. 
 M. BARROWCLIFF, F.I.C. ERIC K. RIDEAL, M.A., PH.D., F.I.C. 
 
 H. GARNER BENNETT, M.Sc. W. H. SIMMONS, B.Sc., F.I.C. 
 
 F. H. CARR, F.I.C. R. W. SINDALL, F.C.S. 
 
 S. HOARE COLLINS, M.Sc., F.I.C. D. A. SUTHERLAND, F.I.C. 
 H. H. GRAY, B.Sc. HUGH S. TAYLOR, D.Sc. 
 
 H. C. GREENWOOD, D.Sc. ARMAND DE WAELE, B.Sc. 
 
 C. M. WHITTAKER, B.Sc. 
 Stc., &c. 
 
EXPLOSIVES 
 
 BY 
 
 E. DE BARRY BARNETT, B.Sc.(Lo ND .), A.I.C. 
 
 CONSULTING CHEMIST AND MANAGER TO BAGLBY, MILLS AND CO., LTD., FORMERLY 
 
 WORKS CHEMIST, NATIONAL EXPLOSIVES CO., LTD., AND WORKS MANAGER, 
 
 STOCKTON-ON-TEES CHEMICAL WORKS, LTD. 
 
 NEW YORK 
 D. VAN NOSTRAND COMPANY 
 
 25 PARK PLACE 
 1919 
 

 PRINTED IN GREAT BRITAIN 
 
GENERAL PREFACE 
 
 THE rapid development of Applied Chemistry in recent years 
 has brought about a revolution in all branches of technology. 
 This growth has been accelerated during the war, and the 
 British Empire has now an opportunity of increasing its 
 industrial output by the application of this knowledge to the 
 raw materials available in the different parts of the world. 
 The subject in this series of handbooks will be treated from 
 the chemical rather than the engineering standpoint. The 
 industrial aspect will also be more prominent than that of 
 the laboratory. Each volume will be complete in itself, and 
 will give a general survey of the industry, showing how 
 chemical principles have been applied and have affected 
 manufacture. The influence of new inventions on the 
 development of the industry will be shown, as also the 
 effect of industrial requirements in stimulating invention. 
 Historical notes will be a feature in dealing with the 
 different branches of the subject, but they will be kept 
 within moderate limits. Present tendencies and possible 
 future developments will have attention, and some space 
 will be devoted to a comparison of industrial methods and 
 progress in the chief producing countries. There will be a 
 general bibliography, and also a select bibliography to follow 
 each section. Statistical information will only be introduced 
 in so far as it serves to illustrate the line of argument. 
 
 Each book will be divided into sections instead of 
 chapters, and the sections will deal with separate branches 
 of the subject in the manner of a special article or mono- 
 graph. An attempt will, in fact, be made to get away from 
 
 434860 
 
vi GENERAL PREFACE 
 
 the orthodox textbook manner, not only to make the treat- 
 ment original, but also to appeal to the very large class of 
 readers already possessing good textbooks, of which there 
 are quite sufficient. The books should also be found useful 
 by men of affairs having no special technical knowledge, but 
 who may require from time to time to refer to technical 
 matters in a book of moderate compass, with references to 
 the large standard works for fuller details on special points 
 if required. 
 
 To the advanced student the books should be especially 
 valuable. His mind is often crammed with the hard facts 
 and details of his subject which crowd out the power of 
 realizing the industry as a whole. These books are intended 
 to remedy such a state of affairs. While recapitulating the 
 essential basic facts, they will aim at presenting the reality 
 of the living industry. It has long been a drawback of our 
 technical education that the college graduate, on commencing 
 his industrial career, is positively handicapped by his 
 academic knowledge because of his lack of information on 
 current industrial conditions. A book giving a compre- 
 hensive survey of the industry can be of very material 
 assistance to the student as an adjunct to his ordinary text- 
 books, and this is one of the chief objects of the present 
 series. Those actually engaged in the industry who have 
 specialized in rather narrow limits will probably find these 
 books more readable than the larger textbooks when they 
 wish to refresh their memories in regard to branches of the 
 subject with which they are not immediately concerned. 
 
 The volume will also serve as a guide to the standard 
 literature of the subject, and prove of value to the con- 
 sultant, so that, having obtained a comprehensive view of 
 the whole industry, he can go at once to the proper 
 authorities for more elaborate information on special points, 
 and thus save a couple of days spent in hunting through the 
 libraries of scientific societies. 
 
 As far as this country is concerned, it is believed that 
 the general scheme of this series of handbooks is unique, 
 and it is confidently hoped that it will supply mental 
 
GENERAL PREFACE vii 
 
 munitions for the coming industrial war. I have been 
 fortunate in securing writers for the different volumes who 
 are specially connected with the several departments of 
 Industrial Chemistry, and trust that the whole series will 
 contribute to the further development of applied chemistry 
 throughout the Empire. 
 
 SAMUEIv 
 
PUBLISHERS' NOTE 
 
 We much regret that, owing to the continued 
 and unexpected increase in the cost of printing 
 since the Armistice, it has been found impossible 
 to publish future volumes in the f< Industrial 
 Chemistry Series " at the price originally fixed 
 f 7/6 each- If, as it is hoped, prices become 
 more reasonable, we propose to revert as nearly 
 as possible to the earlier arrangement. 
 
AUTHOR'S PREFACE 
 
 IN the following pages the author has endeavoured to give 
 a clear but concise account of the manufacture of explosives, 
 together with an outline of the methods used for investi- 
 gating this class of substance. The explosives industry is 
 an important one, both in time of peace and in time of war, 
 and is intimately bound up with the synthetic dyestuff and 
 artificial fertilizer industries. These two latter industries 
 are on the point of being established on what one trusts 
 will be a secure basis in this country, and probably the 
 explosives industry will expand with them. The experience 
 gained by the troops and by the munition workers during 
 the war in the handling and use of explosives should have 
 largely removed the distrust in which these bodies are 
 usually held, and at the same time have demonstrated their 
 manifold uses. It is certain that prior to the war the use 
 of explosives in this country was far too restricted, only 
 small quantities being used for agricultural purposes, such 
 as breaking up subsoil, drainage, etc. In the future it is 
 hoped that they will be more extensively used for general 
 purposes, and this will no doubt prove to be the case if they 
 are made available at a low price. The enormous nitrating 
 plants established for war purposes and the advent of 
 synthetic ammonium nitrate should render this possible 
 with nitrate of ammonia explosives. The author has 
 devoted a special section to Coal Mine Explosives, as the 
 importance of the subject seems to warrant special treat- 
 ment. It is hoped that the British Government will divert 
 some of the money that is to be expended on "Scientific 
 Research " to the investigation of shot firing in coal mines, 
 
x AUTHOR'S PREFACE 
 
 as up to the present they seem to have rested content with 
 carrying out the official tests. It is rather depressing to 
 find that, in spite of our enormous coal fields, we carry out 
 less work on coal mine explosives than any of the important 
 coal -getting countries in either hemisphere. There seems 
 to be no British publication analogous to the excellent 
 " Bulletins of the U.S. Bureau of Mines " or the " Bulletins 
 of the U.S. Bureau of Explosives/' 
 
 The author wishes to acknowledge his indebtedness to 
 C. A. Marshall's invaluable work " Explosives ; their History, 
 Manufacture, Properties and Uses," in which the industry 
 is treated in far greater detail than is possible in a volume 
 of this size. 
 
 E. DE BARRY BARNETT. 
 
 June, 1919. 
 
CONTENTS 
 
 PACK 
 
 GENERAL PREFACE v 
 
 AUTHOR'S PREFACE . ix 
 
 ABBREVIATIONS . ... . xv 
 
 INTRODUCTION 
 
 Historical Sketch. Explosives Act, 1875. Buildings and Safety. Imports 
 
 and Consumption. Official Classification. Bibliography . . i 
 
 SECTION I.-GUNPOWDER 
 
 Composition. First Mixing. Incorporating or Milling. Pressing. Granu- 
 lating or Corning. Glazing. Stoving or Drying. Blending. 
 Moulding. Sodium Nitrate Powders. Sprengsalpeter. Bobbinite. 
 Stability, etc. Literature 17 
 
 SECTION II. EXPLOSIVE COMPOUNDS 
 
 Nitroglycerine. Nitrating House. Separating House. Wash and 
 
 Filter House. After-Separation. Nitrator-Separator . . 31 
 
 Nitrocellulose. Guncotton. Abel Process. Direct Dipping Process. 
 Displacement Process. Nitrating Centrifugals. Collodion. Wash- 
 ing. Pulping .......... 43 
 
 Nitroaromatic Compounds. Dinitrobenzole. Dinitrotoluol. Trinitro- 
 toluol. Picric Acid. Tetranitroaniline. Tetranitromethylaniline . 52 
 
 Miscellaneous Compounds. Nitromethane. Tet rani t torn ethane. Nitro- 
 sugars. Nitro-mannitol. Nitro-starch. Hexanitrodiphenylamine. 
 Hexanitrodiphenyl Sulphide. Hexanitrodiphenyl Oxide. Hexanitro- 
 oxanilide. Hexanitrodiphenyl ....... 61 
 
 Spent Acids. Literature ......... 64 
 
xii CONTENTS 
 
 SECTION III. SMOKELESS PROPELLANTS 
 
 PROPELLANTS FOR RIFLED ARMS. 
 
 PAGE 
 
 Nitroglycerine Propellants, Ballistite. Cordite Mark I. Cordite M.D. 
 
 Filite. Solenite. Wiirfelpulver. Rohrenpulver. Axite. Moddite . 72 
 Nitrocellulose Propellants. U.S. Military Powder. Poudre B . -79 
 
 PROPELLANTS FOR SHOT GUNS 
 
 33-grain Powders. 42-grain Powders. Schultze Powder. Amberite. 
 E.G. Powder. Smokeless Diamond. Poudre S. Poudre J, 
 Poudre M. Poudre T. Mullerite. Fasan. Tiger. Rothweil. 
 Walsrode. Adler-Marke 82 
 
 Aliphatic Solvents. Literature 87 
 
 SECTION IV. BLASTING EXPLOSIVES 
 
 Dynamite and its Congeners. Dynamite No. I. Dynamite No. 2. 
 
 Dynamite No. 3. Giant Powder. French Dynamites. Carbo- 
 
 dynamite. American Straight Dynamites. Ammonia Dynamite. 
 
 Judson Powder. Vulcan Powder. Stump Powder. Low Powder . 93 
 Gelatinized Explosives. Blasting Gelatine. Gelatine Dynamite. 
 
 Gelignite. American Gelatins. French Gommes. Forcite . . 99 
 Chlorate and Perchlorate Mixtures. Sprengel Explosives. Promethee. 
 
 Rack-a-Rock. Liquid Air Explosives. Cheddite. Steelite. 
 
 Yonckite. Blastine. Pernitral i6 
 
 Ammonium Nitrate Explosives. Astralit. Fulmenit. Ammonal. 
 
 Gesteins-Westfalit IX 3 
 
 Tonite. Literature . . !I 5 
 
 SECTION V SAFETY COAL MINE 
 EXPLOSIVES 
 
 Duration of Flame. Test Galleries. German Gallery. Austrian Gallery. 
 Belgian Gallery. French Gallery. U.S. Gallery. British Gallery. 
 Rotherham Test. British Permitted Explosives. Bobbinite. German 
 Explosives. Austrian Explosives. Belgian Explosifs S.G.P. 
 French Explosifs de Surete. Literature . . . . 117 
 
 SECTION VI. PERCUSSION CAPS, 
 DETONATORS AND FUZES 
 
 Caps and Detonators. Mercury Fulminate. Lead Azide. Percussion 
 Caps. Wet Mixing. Dry Mixing. Jelly Bag. Triplex Safety Glass. 
 Cap Filling. Detonators. Composite Detonators. Sizes of Deto- 
 nators. Filling Detonators, Testing Detonators. Electric Detonators 143 
 
 Fuzes. Safety Fuze. Instantaneous Fuze. Quick-Match. Slow-Match. 
 
 Detonating Fuze. Shell Fuzes 156 
 
 Literature ..... 160 
 
CONTENTS xiii 
 
 SECTION VI. MATCHES, PYROPHORIC 
 ALLOYS AND PYROTECHNY 
 
 PAGE 
 
 Matches 162 
 
 Pyrophoric Alloys 168 
 
 Pyrotechny ... 170 
 
 Literature ............ 177 
 
 SECTION VIII. EXPLOSIVE PROPERTIES 
 
 Power and Brisance. Trauzl Lead Block. Mortar. Ballistic Pendulum. 
 
 Brisance Meter . . . 178 
 
 Velocity of Detonation. Mettegang Recorder. Dautrich's Method. 
 Influence of Diameter and Density. Nitroglycerine. American 
 Straight Dynamites. Gelatinized Explosives and Ammonia Dyna- 
 mites. Tables 185 
 
 Pressure, Heat and Temperature. Rodman Gauge. Crusher Gauge. 
 Bichel Recorder. Peteval Recorder. Bombs and Bomb-Calorimeters. 
 Calculation of Temperature . ....... 195 
 
 Chronography. Internal and External Ballistics. Le Boulange Chrono- 
 graph. Klepsydra. Bashforth Chronograph. Schultze-Marcel- 
 Dieprez Chronograph. Mahieu Chronograph .... 202 
 
 Literature .... .,..,... 205 
 
 SECTION IX. SENSITIVENESS AND 
 STABILITY 
 
 Mechanical Shock. Detonation. Influence. Heat and Ignition. Incor- 
 poration. Deliquescence. Exudation. Abel Heat Test. Guttmann 
 Test. Moir Test. Spica Test. Vieille Test. Waltham Abbey 
 Silvered Vessel Test. German 135 C. Test. Will Test . . 207 
 
 Literature 225 
 
 CONCLUSION . 227 
 
 INDEX . 235 
 
ABBREVIATIONS 
 
 * 
 
 LITERATURE 
 
 A. Annalen der Chemte. 
 A.E. Arms and Explosives. 
 
 A.R. Annual Report of H.M. Inspector of Explosives. 
 
 B. Berichte des Deutschen Chemischen Gesellschaft. 
 C.r. Comptes r endues. 
 
 J.S. C. 1, Journal of the Society of Chemical Industry. 
 
 P.S. Memorial des Poudres et Salpetres. 
 
 Soc. Transactions of the Chemical Society. 
 
 S.R. Special Report by H.M. Inspector of Explosives. 
 
 S.S. Zeitschrift f. Gesamte Schiess u. Sprengstoff Wesen. 
 
 D.R.P. Deutsches Reichs Patent. 
 
 A. P. American Patent. 
 
 E.P. English Patent. 
 
 F.P. French Patent. 
 
 COMPOUNDS, ETC. 
 
 The following abbreviations, which are current in all explosives works in 
 Great Britain, are used throughout the text : 
 
 E.G. Blasting Gelatine. M.N.N. Mononitronaphthalene. 
 
 C.C. Collodion Cotton. M.N.T. Mononitrotoluol. 
 
 D.N.B. Dinitrobenzole. N.C. Nitrocellulose. 
 
 D.N.N. Dinitronaphthalene. N.G. Nitroglycerine. 
 
 D.N.T. Dinitrotoluol. P.A. Picric Acid. 
 
 G.C. Guncotton. T.N.A. Tetranitroaniline. 
 
 G.P. Gunpowder. T.N.N. Trinitronaphthalene. 
 
 MJ. Mineral Jelly. T.N.T. Trinitrotoluol. 
 
 M.N.B. Mononitrobenzole. W.M. Wood Meal. 
 
 M.A. is mixed acid (nitric and sulphuric) and N.A. nitric acid of any strength, 
 the monohydrate being denoted by its chemical formula, HNO 3 . S.A. is sul- 
 phuric acid of any strength, the commercial concentrated acid (168 Tw.) being 
 denoted by C.O.V. (concentrated oil of vitriol), D.O.V. (double oil of vitriol) or 
 R.O.V. (rectified oil of vitriol). The monohydrate is denoted by its chemical 
 formula, H 2 SO 4 . The fuming acid is known as " oleum," or much less frequently 
 as F.O.V. or N.O. V. (fuming oil of vitriol, Nordhausen oil of vitriol). 
 
EXPLOSIVES 
 
 INTRODUCTION 
 
 Historical Sketch. The origin of gunpowder, which was 
 the only explosive known until the middle of the nine- 
 teenth century, is uncertain. Some authors regard Greek 
 Fire, rather extensively used in the defence of Constanti- 
 nople in the seventh century, as a form of gunpowder, 
 but it seems reasonably certain that this was merely an 
 incendiary mixture to which crude nitre may or may not 
 have been added in order to make it burn more fiercely. 
 The Chinese seem to have made use of gunpowder in war- 
 fare about 1232, and the writings of Roger Bacon contain 
 directions for the purification of nitre and anagrams and 
 cryptograms which appear to describe the preparation of 
 gunpowder, although some doubt has been cast on their 
 authenticity. His later works, however, notably " Opus 
 Tertium," " De Secretis," and "Opus Magnus," leave no 
 doubt that he was acquainted with explosive mixtures of 
 sulphur, charcoal, and nitre. About this period also, the 
 Arabs seem to have had knowledge of the explosive pro- 
 perties of similar mixtures. 
 
 The early uses of gunpowder were confined to warfare, 
 and no use seems to have been made of it for blasting 
 purposes for several hundred years. It was originally used 
 in the form of crude hand grenades, and probably was at 
 first of most use in striking terror into the enemy. Cannon 
 were first used by the English in 1346 at the battle of 
 Crecy, but seem to have been used a few years prior to 
 this in the Hispano-Moorish wars. 
 
 manufacture of gunpowder was originally carried 
 
-EXPLOSIVES 
 
 out by the very crude method of pounding the ingredients 
 together by hand in mortars, but edge runners were intro- 
 duced towards the end of the sixteenth century. The 
 original mixtures were of very fine grain, were deliquescent, 
 and the ingredients separated very easily when the powder 
 suffered vibration as in transport. In the fourteenth 
 century attempts were made to avoid this latter defect by 
 the addition of camphor, sal-ammoniac and gum, and in 
 the sixteenth century the process of " corning " or " granu- 
 lating " was introduced. This was done by moistening 
 the powder during the latter stages of mixing, so as to obtain 
 a cake which was subsequently broken up and sifted. 
 
 Fuzed shell were first introduced in 1588, but the fuzes 
 were naturally of a very crude nature. More accurate 
 fuzes were employed by the British at the siege of Gib- 
 raltar in 1779, and shrapnel shell was introduced a few 
 years later. 
 
 Berthollet, as a result of his researches on chlorates, in 
 1788 suggested substituting potassium chlorate for nitre, 
 and obtained a more powerful explosive by this means, 
 but it was too dangerous to make or use. A chlorate powder, 
 however, was adopted in 1805 by Forsyth as a priming 
 charge. 
 
 Fulminate caps seem to have come into use first about 
 1815, and in 1831 Bickford first introduced safety fuze. 
 The discovery of guncotton by Schonbein in 1845, and of 
 nitroglycerine by Sobrero in 1846, opened up new fields, 
 although the accidents attendant on the manufacture of 
 these substances at first greatly delayed their general intro- 
 duction. Schonbein sold the British rights of his patent 
 to John Hall and Sons, of Faversham, who manufactured 
 guncotton for a few months, but abandoned it in 1847, 
 after a disastrous explosion. Six years later the Austrian 
 Government took up the matter, and General von I,enk 
 constructed some batteries in which guncotton was used 
 both as a propellant and as a bursting charge for the shell. 
 These were not an unmitigated success, and after two 
 disastrous explosions in 1865, they were abandoned./ 
 
 ^ 
 
INTRODUCTION 3 
 
 In the meantime the British Government had taken 
 up the subject, and Frederick Abel carried out investiga- 
 tions on their behalf. He quickly realized that the insta- 
 bility of guncotton was due to the difficulty in washing it, 
 and in 1865 introduced the pulping process. Simple as it 
 may seem, this must be regarded as an epoch-making dis- 
 covery, as it at once changed a very dangerous process into 
 one of the safest known in an explosives works. Also the 
 wet pulp could be compressed into blocks which were 
 convenient for transport and use. The usefulness of these 
 blocks was greatly enhanced by the discovery by Braun 
 in 1868 that dry guncotton could be fired by a fulminate 
 detonator, and that wet guncotton could be fired in the same 
 way if a small primer of dry guncotton was used. The 
 value of this discovery will be realized when it is remem- 
 bered that wet guncotton is non-inflammable and in- 
 sensitive to shock. These slabs of wet guncotton have for 
 many years been the standard explosive for military demoli- 
 tions and for signal maroons, and until quite recently have 
 been the invariable charge for torpedoes. 
 
 As stated above, nitroglycerine was discovered in 1846 
 by Sobrero, who, however, does not seem to have attached 
 any importance to the discovery, and it was not until Alfred 
 Nobel took up the subject in 1862 that any attempt was made 
 to employ it as an explosive. In this year Nobel commenced 
 its manufacture near Stockholm in Sweden, but the numerous 
 accidents that accompanied its use soon led to its prohibi- 
 tion by all countries. Nobel then sought for a means of 
 rendering it more safe, and discovered in 1867 that this 
 could be done by absorbing it in some porous material. 
 The most suitable material of this nature was found to be 
 kieselguhr, good qualities of which will take up three times 
 their weight of nitroglycerine and still remain dry, although 
 Nobel also patented the use of other porous materials, such 
 as brick dust, plaster, etc. 
 
 A great advance was made in 1875, when Nobel intro- 
 duced his first gelatinous explosive. The discovery of this 
 is said to have been due to an accident, Nobel having used 
 
4 EXPLOSIVES 
 
 collodion solution to close a cut in his hand and then having 
 noticed that this formed a jelly with the nitroglycerine with 
 which he was carrying out some experiments later in the 
 day. The first explosive of this nature, Blasting Gelatine, 
 contained about 92 per cent, of nitroglycerine and 8 per 
 cent, of collodion cotton. It experienced an immediate 
 success, but a demand at once arose for less violent and 
 less brisant explosives of the same nature. These were 
 readily made by, preparing a thinner jelly and then doping 
 with potassium nitrate and wood meal. Mixtures of this 
 nature have met with very wide use under the names of 
 Gelatine Dynamite and Gelignite, Gelatine Dynamite being 
 stronger than Gelignite, but not so strong as Blasting 
 Gelatine. 
 
 A new class of explosive was introduced by Sprengel 
 in 1871. He found that mixtures of suitable organic 
 matter, such as nitrobenzole, and strong or fuming nitric 
 acid or liquid nitrogen tetr oxide, could be detonated. 
 These had the advantage that the ingredients were kept 
 separate and only mixed just before the shot was fired, and 
 although nitric acid is an inconvenient liquid to transport, 
 Sprengel explosives enjoyed some vogue. A more rational 
 explosive of the Sprengel class was introduced by Devine in 
 1880. This consisted in a cartridge of potassium chlorate 
 which immediately before use was dipped into an organic 
 liquid such as nitrobenzole. Rock-a-rock was an explosive 
 of this nature, and was used in 1885 for blasting Hell Gate 
 Rock in New York harbour. The first ammonium nitrate 
 explosive was introduced by Favier in 1885, but attracted 
 scant attention at the time on account of its objectionable 
 hygroscopic properties. Finally, in recent years proposals 
 have been made to employ mixtures of liquid air or oxygen 
 in conjunction with organic matter, and although a good 
 deal of the blasting in connection with the Simplon tunnel 
 was carried out with explosives of this class, they suffer 
 from obvious disadvantages and are never likely to come 
 into general use. They have been used, however, for 
 general blasting purposes in Germany during the war. 
 
INTRODUCTION 5 
 
 It may be mentioned that explosives of the Sprengel class 
 have never been used in this country, as mixing the in- 
 gredients is regarded as a process of manufacture within the 
 meaning of the Act, and as such can only be carried on on 
 licensed premises (Explosives Act, 1875). 
 
 As stated on page 2, Berthollet in 1788 was the first to 
 propose the use of chlorates, but was compelled to abandon 
 the scheme on account of the great sensitiveness of his 
 mixtures. This danger was remedied by Street in 1897, who 
 prepared safe chlorate mixtures from potassium chlorate and 
 castor oil thickened with a nitrohydrocarbon. These have 
 met with considerable success under the name of Cheddite. 
 
 The first smokeless powder after von I,enk's nitrocotton 
 batteries was introduced by Schultze in 1865. It con- 
 sisted of pellets of wood which were nitrated and then 
 impregnated with barium nitrate and/or potassium nitrate. 
 A great stride was made by Volkmann five years later, who 
 partly gelatinized nitrated wood by treatment with a mixture 
 of alcohol and ether. This must be regarded as having laid 
 the foundation of the modern smokeless powder industry. 
 A similar powder, B.C. Powder, was introduced in 1882 
 by the Explosives Company of Stowmarket. It consisted 
 of partly gelatinized nitrocotton impregnated with a mixture 
 of barium and potassium nitrates, and found immediate 
 favour among sportsmen. 
 
 The first smokeless military powder was Poudre B, 
 introduced by Vielle in 1886, and adopted by the French 
 Government. It was made by forming a dough of nitro- 
 cellulose with alcohol and ether, which was then rolled out 
 into sheets, cut up into strips, and dried. 
 
 Two years later Nobel introduced Ballistite, made by 
 gelatinizing soluble nitrocellulose with nitroglycerine, and 
 in the same year the British Government introduced Cordite, 
 made by gelatinizing guncotton with nitroglycerine and 
 acetone. These rival discoveries led to a lawsuit, the issue 
 of which turned on the definition of nitrocellulose. 
 
 Sprengel in 1871 drew attention to the fact that picric 
 acid could be detonated, but no use was made of this 
 
6 EXPLOSIVES 
 
 discovery until Turpin proposed its use in 1886 as a bursting 
 charge for shells. For this purpose it found wide application 
 under the names of Melinite, L,yddite, etc., but has now been 
 largely replaced by the cheaper and safer trinitrotoluol. 
 
 Tetranitroaniline and tetranitromethyl aniline were dis- 
 covered by Flursheim in 1910, but at present their cost 
 of manufacture precludes their use except in detonators, 
 in which they are likely to find extensive employment. 
 
 The general introduction of explosives for blasting 
 purposes led to a considerable increase in coal-mine accidents, 
 due to the shot firing the mine gases or causing a dust 
 explosion. Macnab in 1873 first suggested remedying this 
 by placing a cylinder of water in front of the charge, and this 
 was shortly followed by suggestions involving the employ- 
 ment of jellies containing 90 per cent, of water, wet moss 
 or salts rich in water of crystallization in the same way. 
 None of these were altogether successful, but the setting 
 up of experimental galleries in 1885 by the Prussian and 
 other governments soon led to the discovery that as a rule 
 ammonium nitrate explosives are the safest to use in fiery 
 mines. The conditions which must be fulfilled by an ex- 
 plosive for use in fiery mines are now stringent, and in order 
 to fulfil them it is necessary to add a considerable amount 
 of an inactive salt to the explosive. It was not until 1913 
 that a gelatinous explosive was discovered which would 
 pass the Rotherham test, in which year Messrs. Curtis and 
 Harvey, I/td., patented Super- Rippite. 
 
 Explosives Act, 1875. The Explosives Act, 1875, is 
 entitled " An Act to amend the law with respect to manu- 
 facturing, keeping, selling, carrying and importing gun- 
 powder, nitroglycerine and other explosive substances/' 
 The third section of the Act defines an explosive as " . . . 
 gunpowder, nitroglycerine, blasting powders, fulminate of 
 mercury or of other metals, coloured fires, and every other 
 substance, whether similar to those above mentioned or not, 
 used or manufactured with a view to produce a practical 
 eff ect by explosion or a pyrotechnic effect ; and includes fog- 
 signals, fireworks, fuzes, rockets, percussion caps, detonators, 
 
INTRODUCTION 7 
 
 cartridges, ammunition of all descriptions, and every adop- 
 tion or preparation of an explosive as so defined." Section 
 104 of the Act gives power to include any specially dangerous 
 substance even if not manufactured or used " to produce 
 a practical effect by explosion/' Acetylene, for example, 
 under certain conditions is included under the Act. The 
 Explosives Act prohibits the manufacture of any explosive 
 on any premises not duly licensed, fixes the minimum dis- 
 tance of such premises from private dwellings, public roads, 
 etc., and establishes procedure for granting such licences. 
 It provides safeguards for workers, insists that each separate 
 building in a factory shall be separately licensed and the 
 amount of explosive and the number of workers in it at any 
 time limited. It prohibits certain dangerous processes and 
 mixtures, such as mixtures of chlorates and sulphur, and 
 endows the inspectors under the Act with wide powers. 
 The Act must be regarded as a very fair one, and is ad- 
 ministered with extremely little friction in view of the 
 stringency of its provisos. 
 
 Buildings and Safety. Owing to the dangerous nature 
 of the material handled, manufacturing operations are 
 carried out in a series of small separate huts, the number of 
 workers in any hut rarely exceeding five, although in some 
 of the less dangerous processes this number may be exceeded. 
 The danger buildings in an explosives factory can be roughly 
 divided into two classes, viz. (a) magazines used for storing 
 explosives, and (b) buildings used for manufacturing purposes. 
 The former of these should be of strong construction, so as 
 to prevent the entrance of any unauthorized person. They 
 are usually built of stone or brick, with double doors, the 
 outer door generally being sheathed in iron. Working 
 buildings, on the other hand, should be of as light and 
 flimsy a character as possible, so that in case of an explosion 
 heavy debris is not thrown about. They are usually 
 constructed of light matchboard, the roof being of the same 
 material and covered with some non-inflammable sheet. 
 A light, ferroconcrete construction has been proposed as 
 suitable for danger buildings, as it has been urged that an 
 
S EXPLOSIVES 
 
 explosion would reduce it to powder, but the suggestion has 
 not been adopted. 
 
 All danger buildings must be surrounded by an earth 
 mound reaching to the roof, so as to deflect the explosive 
 wave upwards in case of an explosion. The entrance 
 through the mound should be directly opposite the door of 
 the building when possible. The floors of danger buildings 
 are usually covered with oilcloth, or in some cases with 
 sheet lead. They must be washed thoroughly every day, 
 and when dusty material such as dry guncotton is being 
 dealt with must be kept wet while work is being carried on. 
 All windows must be made of frosted glass so as to exclude 
 direct sunlight, and all doors must open outwards. Further, 
 the doors must be provided with a brass lock and key, for 
 securing them when work is not being carried on, but when 
 occupied by workers must be closed only by a spring catch, 
 so that they can be opened by a push in case of emergency. 
 The brass work must either be kept bright or painted over. 
 Artificial light when required is provided by incandescent 
 electric lamps. These are enclosed in a glass bell and then 
 set in recesses in the walls, and separated from the inside of 
 the building by a thick plate of glass. All switches, etc., 
 must be external to the building. All workers must wear 
 special clothes made of wool and without pockets, and must 
 carry with them no metallic articles, such as metal buttons, 
 jewellery, etc., nor any smoking materials or matches. 
 Danger buildings are all " clean " buildings, and must not 
 be entered unless the person entering dons special shoes. 
 Workers usually wear slippers without nails, felt slippers 
 or rubber boots. These are kept in a cupboard in the porch 
 of the building, and are donned just before stepping over 
 the barrier, so that they never come into contact with the 
 ground outside the clean building. The barrier is usually 
 a strip of wood about eight inches high, set at the door of 
 the building to denote the point at which the clean area 
 commences. Magazines and some other buildings can be 
 entered by wearing leather overshoes kept specially for the 
 purpose, but this is not permitted in all buildings. As some 
 
INTRODUCTION 9 
 
 explosives are easily electrified, it is advisable that workers' 
 shoes should be provided with a few copper studs in the 
 sole, so as to " earth " the wearer. This is particularly 
 the case when reeling cordite and when handling dry gun- 
 cotton. Of course all buildings must be adequately pro- 
 tected against lightning, and when possible work must be 
 stopped during thunderstorms. 
 
 The manufacture of explosives as carried out in this 
 country must be regarded as one of the safest of the dangerous 
 trades, the average number of fatalities per annum for the 
 decade 1904-1914 being 7*7. The following is a summary of 
 the number of accidents, deaths, and injuries which occurred 
 in manufacturing operations in the explosives trade during 
 the years 1911-1914 inclusive : 
 
 Year. 
 I9II 
 1912 
 1913 
 1914 . . 
 
 In relation to the number of accidents, it must be borne in 
 mind that any accident due to explosion, no matter how 
 trivial, must be reported. During the war the number of 
 accidents and the number of killed and injured greatly 
 exceeded these figures, but this must be ascribed to the 
 enormously increased production, accompanied by intensive 
 working and dilution of labour. 
 
 Imports and Consumption. The consumption of ex- 
 plosives in Great Britain is chiefly supplied by the various 
 explosive factories in the country, but some explosive is 
 imported. The following figures denote the chief blasting 
 explosives imported in 1912 and 1913, but a large pro- 
 portion was only imported in transit and was not con- 
 sumed : 
 
 1912. 1913. 
 
 Blasting Gelatine .. .. 17,512 Ibs. 240,393153. 
 
 Dynamite .. .. .. 116,370 ,, 218,741 
 
 Gelignite 280,488 686,995 
 
 No. of 
 
 
 
 Accidents. 
 
 Killed. 
 
 Injured 
 
 . 6 9 
 
 13 
 
 40 
 
 . 104 
 
 I 
 
 33 
 
 . 86 
 
 13 
 
 50 
 
 . 92 
 
 21 
 
 4i 
 
10 
 
 EXPLOSIVES 
 
 No data is available as regards the consumption of 
 sporting powder, but the consumption of blasting explosives 
 is reported under the Mines and Quarries Act, and the figures 
 for 1910 and 1911 give a good idea of the extent of the 
 industry 
 
 Gunpowder 
 
 Permitted Explosives 
 
 Gelignite 
 
 Gelatine Dynamite 
 
 Blasting Gelatine 
 
 Cheddite 
 
 Other Explosives 
 
 Total 
 
 1910. 
 
 17,664,483 Ibs 
 8,607,882 
 
 494,560 
 257.756 
 
 123,584 
 350,600 
 
 .. 30,538,121 
 
 1911. 
 17,305,073 Ibs 
 
 9,340, 33 
 
 3,294,423 
 
 472,464 
 
 244,*55 
 110,761 
 
 53 >979 
 31,297,888 
 
 In the United States the industry is much larger than in 
 this country, the home consumption for the years 1914-1917 
 being 
 
 1914. 1915. 1916. 1917. 
 
 Black Blasting Powder 206,099,700 197,722,300 215,575,025 277,118,525 
 High Explosives .. 218,453,971 235,828,587 255,154,787 262,316,080 
 Permissible Explosives 25,697,818 27,349,909 34,685,240 43,040,722 
 
 Total 
 
 450,251,489 460,900,796 55,4 I 5,52 582,475,327 
 
 all amounts being in pounds. L,arge as these figures are, 
 they do not include the very considerable export trade 
 carried on, the figures for which during the corresponding 
 years were 
 
 Year. 
 
 Dynamite, etc. 
 
 Gunpowder. 
 
 Cartridges. 
 
 Other 
 explosives. 
 
 Weight 
 (Ibs.) 
 
 Value (U.S. 
 Dollars.) 
 
 Weight 
 (Ibs.) 
 
 Value (U.S. 
 Dollars.) 
 
 Value (U.S. 
 Dollars.) 
 
 Value (U.S. 
 Dollars.) 
 
 1914 
 
 1915 
 1916 
 1917 
 
 11,296,115 
 11,446,368 
 18,601,285 
 17,930,665 
 
 1,213,600 
 1,509,050 
 4.173,175 
 3,653,374 
 
 896,569 
 
 84,358,379 
 303,648,981 
 446,540,999 
 
 291,453 
 66,922,807 
 262,116,893 
 331,163,229 
 
 6,567,122 
 25,408,079 
 55,103,904 
 42,122,656 
 
 1,965,412 
 95,129,957 
 394,136,334 
 255,944,315 
 
 Classification. The following is the . British Official 
 classification of explosives extracted verbatim from the 
 " List of Authorized Explosives," 1918 : 
 
INTRODUCTION n 
 
 Class I. Gunpowder 
 
 The term " gunpowder " means exclusively gunpowder 
 ordinarily so called. 
 
 Class II. Nitrate Mixture 
 
 The term " nitrate mixture " means any preparation, 
 other than gunpowder ordinarily so called, formed by the 
 mechanical mixture of a nitrate with any form of carbon 
 or with any carbonaceous substance not possessed of ex- 
 plosive properties, whether sulphur be or be not added to 
 such preparation, and whether such preparation be or be not 
 mechanically mixed with any other non-explosive substance. 
 
 Every blasting explosive of this class, in which nitrate of 
 ammonium, nitrate of sodium or chloride of sodium are used 
 as ingredients, shall be contained in cartridge wrappers or cases 
 (or in 5 Ib. inner packages) made thoroughly waterproof 
 with melted paraffin or other suitable waterproofing material. 
 
 Class III. Nitro-Compound 
 
 The term " nitro-compound " means any chemical com- 
 pound possessed of explosive properties, or capable of com- 
 bining with metals to form an explosive compound, which 
 is produced by the chemical action of nitric acid (whether 
 mixed or not with sulphuric acid) or of a nitrate mixed 
 with sulphuric acid upon any carbonaceous substance, 
 whether such compound is mechanically mixed with other 
 substances or not. 
 
 The nitro-compound class has two divisions. 
 
 Every explosive of this class and every explosive in- 
 gredient thereof shall be so thoroughly purified and other- 
 wise of such a character as to satisfy a test known as the 
 Heat Test, and specified in a Memorandum signed by a 
 Government Inspector and dated the 2nd of February, 1914.* 
 
 Every blasting explosive in this class, in which nitrate 
 of ammonium, nitrate of sodium or chloride of sodium are 
 
 * See Section IX. 
 
12 EXPLOSIVES 
 
 used as ingredients, shall be contained in cartridge wrappers 
 or cases (or in 5 Ib. inner packages) made thoroughly water- 
 proof with melted paraffin or other suitable waterproofing 
 material. 
 
 Division i comprises any chemical compound or mechanic- 
 ally mixed preparation which consists either wholly or partly 
 of nitroglycerine or of some other liquid nitro-compound. 
 
 Provided that every explosive in this Division shall be 
 of such a character and consistency as not to be liable to 
 liquefaction or exudation. 
 
 Provided also that an explosive that is required by 
 definition to be issued in waterproof inner packages may 
 be exempted from such requirement by Special Authority, 
 when and so long as the conditions of such Authority are 
 observed. 
 
 Division 2 comprises any nitro-compound as before 
 defined, which is not comprised in the first division. 
 
 Class IV. Chlorate Mixture 
 
 The term " chlorate mixture " means any explosive 
 containing a chlorate. 
 
 The chlorate mixture class has two divisions. 
 
 Every explosive of this class, and every explosive in- 
 gredient thereof, shall be so thoroughly purified and other- 
 wise of such a character as to satisfy a test known as the 
 Heat Test, and specified in a Memorandum signed by a 
 Government Inspector and dated the 2nd February, 1914.* 
 
 Bvery blasting explosive in this class in which nitrate 
 of ammonium, nitrate of sodium or chloride of sodium are 
 used shall be contained in cartridge wrappers or cases (or 
 in 5 Ib. inner packages) made thoroughly waterproof with 
 melted paraffin or other suitable waterproofing material. 
 
 Division i comprises any chlorate preparation which 
 consists partly of nitroglycerine or of some other liquid 
 nitro-compound. f 
 
 Provided that every explosive in this Division shall be 
 
 * See Section IX. 
 
 t No explosive of this division is at present authorized. 
 
INTRODUCTION 13 
 
 of such a character and consistency as not to be liable to 
 liquefaction or exudation. 
 
 Division 2 comprises any chlorate mixture as before 
 defined, which is not comprised in the first division. 
 
 Class V. Fulminate 
 
 The term "fulminate" means any chemical compound 
 or mechanical mixture, whether included in the foregoing 
 classes or not, which, from its great susceptibility to detona- 
 tion, is suitable for employment in percussion caps or any 
 other appliances for developing detonation, or which, from 
 its extreme sensibility to explosion, and from its great 
 instability (that is to say, readiness to undergo decomposition 
 from very slight exciting causes), is especially dangerous. 
 
 This class consists of two divisions. 
 
 Division i comprises such compounds as the fulminates 
 of silver and of mercury, and preparations of these sub- 
 stances, such as are used in percussion caps ; and any 
 preparation consisting of a mixture of a chlorate with phos- 
 phorus, or certain descriptions of phosphorus compounds, 
 with or without the addition of carbonaceous matter, and 
 any preparation consisting of a mixture of a chlorate with 
 sulphur, or with a sulphuret, with or without carbonaceous 
 matter.* 
 
 Division 2 comprises any such substance as the chloride 
 and the iodide of nitrogen, fulminating gold and silver, 
 diazobenzol, and the nitrate of diazobenzol.f 
 
 Class VI. Ammunition 
 
 The term " ammunition " means an explosive of any of 
 the foregoing classes when enclosed in any case or con- 
 trivance, or otherwise, adapted or prepared to form a 
 cartridge or charge for small arms, cannon, or any other 
 weapon, or for blasting, or to form any safety or other fuze 
 for blasting, or for shells, or to form any tube for firing 
 
 * The only explosive of this division at present authorized is mercury 
 fulminate. 
 
 f The only explosive of this division at present authorized is lead azide. 
 
14 EXPLOSIVES 
 
 explosives, or to form a percussion cap, a detonator, a fog- 
 signal, a shell, a torpedo, a war rocket, or other con- 
 trivance other than a firework. 
 
 The term " percussion cap " does not include a deto- 
 nator.* 
 
 The term " detonator " means a capsule or case which 
 is of such strength and construction and contains an ex- 
 plosive of the fulminate explosive class in such quantity 
 that the explosion of one capsule or case will communicate 
 the explosion to other like capsules or cases. 
 
 The term " safety fuze " means a fuze which burns and 
 does not explode, and which does not contain its own means 
 of ignition, and which is of such strength and construction 
 and contains an explosive in such quantity that the burning 
 of such fuze will not communicate laterally with other 
 like fuzes. 
 
 The ammunition class has three divisions. 
 
 Division i. No official definition of Division i is given, 
 but it includes safety electric fuzes, percussion caps and 
 railway fog-signals. 
 
 Division 2 comprises any ammunition as before defined 
 which does not contain its own means of ignition, and is not 
 included in Division i. 
 
 Division 3 comprises any ammunition as before defined 
 which contains its own means of ignition and is not included 
 in Division i. 
 
 Class VII. Firework 
 
 The term " firework " comprises firework composition 
 and manufactured fireworks. 
 
 Division i. Firework composition.! 
 
 Division 2. Manufactured fireworks, consisting of any 
 
 * A percussion cap can only be properly classed as such if it contains 
 less than *6 grain of a composition of the ist Division of the 5th (Fulminate) 
 class of which not more than 25 per cent, consists of fulminate of mercury, 
 or less than '5 grain of any other explosive of the ist Division of the 5th 
 (Fulminate) class. And it has been further decided that percussion caps 
 shall not be classed as such when they contain anvils or have their composi- 
 tion unprotected by tinfoil or other suitable substance. 
 
 f No explosive of this division is at present authorized. 
 
INTRODUCTION 15 
 
 explosive of the foregoing classes, and any firework com- 
 position, when such explosive or composition is enclosed in 
 any case or contrivance, or is otherwise manufactured so 
 as to form a squib, cracker, serpent, rocket (other than a war 
 rocket), maroon, lance, wheel, and Chinese fire, Roman 
 candle, or other article specially adapted for the production 
 of pyrotechnic effects or pyrotechinc signals, or sound 
 signals. Provided that a substantially constructed and 
 hermetically closed metal case containing not more than 
 i Ib. of coloured fire composition of such a nature as not to 
 be liable to spontaneous ignition shall be deemed to be 
 a manufactured firework. Provided also that the term 
 " manufactured firework " shall not be deemed to include 
 any explosive hereinafter mentioned, by whatever name 
 known, or any colourable imitation of the same. 
 
 BIBLIOGRAPHY 
 
 A. Marshall, " Explosives." London, 1917. 
 O. Guttmann, " Manufacture of Explosives." London, 1895. 
 P. C. Sanford, " Nitroexplosives." London, 1906. 
 E. de W. S. Colver, " High Explosives." London, 1918. 
 W. Walke, " Lectures on Explosives." London, 1897. 
 H. W. L. Hime, " Gunpowder and Ammunition." London, 1904. 
 E. M, Weaver, " Military Explosives." London, 1917. 
 R. Molina, " Les Explosifs et leur Fabrication." French translation by 
 J. A. Montpelier. Paris, 1909. 
 
 J. Daniel, " Dictionaire des Matieres Explosives." Paris, 1902. 
 L. Gody, " Matieres Explosives." Paris, 1907. 
 L. Vennin and G. Chesneau, " Poudres et Explosifs." Paris, 1914. 
 P. F. Chalon, " Les Explosifs Modernes." Paris, 1911. 
 R. Escales, " Die Explosivstoffe." Leipzig, 1905-1915. 
 Heft I. " Schwartzpulver u. Sprengsalpeter." 1914. 
 Heft II., " Schiessbaumwolle." 1905. 
 Heft III., " Nitroglyzerin u. Dynamit." 1908. 
 Heft IV., " Ammonsalpetersprengstoffe." 1909. 
 Heft V., " Chloratsprengstoffe." 1910. 
 Heft VI., " Nitrosprengstoffe." 1915. 
 
 H. Brunswig, " Die Explosivstoffe." English translation by C. E. 
 Munroe and A. L. Kibler. New York, 1912. 
 
 A. Voigt, " Die Hertsellung der Sprengstoffe." Halle, 1913-1914. 
 Theil I. Schwartzpulver. 
 
 Chloratsprengstoffe. 
 Schiessbaumwolle . 
 Rauchschwache Schiesspulver. 
 Theil II. Nitroglyzerin. 
 Dynamit. 
 Sicherheitssprengstoffe. 
 
16 EXPLOSIVES 
 
 F. Salvati, " Volcabolario di Polveri Ed Explosivi." Rome, 1893. 
 
 R. Aranaz, " Los Explosives Militates." Granada, 1904. 
 
 J. M. Vivas J. R. Feigenspan, and J. F. Ladreda, " Polvoras y Explo- 
 sives." Segovia, 1915. 
 
 An invaluable book on the legislation affecting the manufacture and 
 storage of explosives has been prepared by Capt. J. H. Thomson, entitled 
 " Guide to the Explosives Act, 1875." The last edition was published in 
 1917. 
 
 A bibliography of the chief works on ballistics will be found at the end 
 of the section on Propellants. 
 
 The chief periodicals dealing with explosives are 
 
 Arms and Explosives . London . 
 
 Zeitschrift f. Gesamte Schiess- und Sprengstoff-wsen. Munich. 
 
 Sprengstoffe, Waffen u. Munition. Berlin. 
 
 Memorial des Poudres et Salpetres. Paris. 
 
 Very valuable information is also published from time to time in the 
 " Bulletins " and " Technical Papers " of U.S. Bureau of Mines and the 
 U.S. Bureau of Explosives. 
 
SECTION L GUNPOWDER 
 
 GUNPOWDER remained the only known explosive until the 
 middle of the nineteenth century, and at the present time 
 is still the most used explosive except for military purposes. 
 For military purposes its use is now limited to bursting 
 charges for shrapnel shell, to time fuzes, and to priming 
 composition for use with cordite, but it is still largely used 
 as a sporting powder, chiefly on account of its cheapness. 
 The same consideration, and the fact that it does not require 
 a detonator, has led to its retention for blasting purposes, 
 about 55 per cent, of the explosive used for blasting in 
 Great Britain in 1911 being gunpowder. 
 
 Compared with modern high explosives Gunpowder is 
 greatly lacking in power, the Trauzl block test giving figures 
 of about 108 as compared with 520 for Dynamite No. i 
 and 650 for Blasting Gelatine. Gunpowder has the advantage, 
 however, of being less brisant than most explosives, a great 
 advantage when dealing with soft material which it is 
 desired to obtain in big lumps. 
 
 Gunpowder invariably consists in this country of a 
 mixture of potassium nitrate, sulphur, and charcoal, although 
 in America and in Germany large quantities are consumed in 
 which the cheaper sodium nitrate has been substituted for 
 the potassium salt. These sodium nitrate powders are 
 cheaper and somewhat more powerful than those made 
 with potassium nitrate, but their deliquescent properties 
 are a great drawback. They have been used in Great 
 Britain since the outbreak of war cut off the potash 
 supplies from Germany. 
 
 In manufacturing gunpowder some care is required in 
 the selection of material. The nitre should be almost 
 chemically pure, be quite neutral to litmus, and quite free 
 T. 2 
 
i8 EXPLOSIVES 
 
 from chlorate and perchlorate, especially the former. It 
 should not contain more than the merest trace of chloride, 
 under -01 per cent, calculated as NaCl, as otherwise it will 
 become deliquescent. 
 
 The sulphur must contain no non-volatile matter, and 
 must be free from sulphuric acid. As commercial flowers 
 of sulphur almost invariably contains some acid, it is usual 
 to use roll sulphur and grind this down. The quality of the 
 powder depends a great deal on the quality of the charcoal, 
 so that it is customary for powder mills to prepare their own. 
 The wood most employed in this country is alder wood and 
 dog wood, but hazel, willow, yew, hemp, and poplar are all 
 used. The German cocoa powder, one of the best gunpowder 
 propellants for cannon ever made, was prepared from 
 rye straw charcoal. It has, however, been completely 
 superseded by the modern smokeless powders. 
 
 Timber intended for gunpowder charcoal should be 
 cut in the spring, and then kept for from three months to 
 three years in order to allow the sap to evaporate. The 
 bark is then removed and the wood cut up and carbonized 
 in iron cylinders. 
 
 Various forms of retorts have been proposed, but the 
 most generally used is in the form of a cylinder 4 ft. 6 in. long 
 by 2 ft. 4 in. diameter. These are charged with the wood 
 and then closed, except for a vent to allow the escape of the 
 products of distillation. The retort is then slid into the 
 furnace and carbonization carried out for 4 to 5 hours at 
 a temperature between 400 C. and 500 C. The crude 
 pyroligneous acid that distils off can be collected and worked 
 up for acetic acid, acetone, etc., but the amounts are so 
 small that the distillate is usually led direct to the furnace 
 and burnt. When carbonization is complete the retort is 
 removed from the furnace, completely closed and set aside 
 to cool. Air must not be admitted until the charge has 
 cooled, and even then only slowly, as freshly made charcoal 
 absorbs air with avidity, and may inflame. It is for this 
 reason that movable retorts are usually preferred to fixed 
 ones, although both types are used. 
 
GUNPOWDER ig 
 
 The composition of gunpowder varies a good deal with 
 the different grades manufactured. French military powders 
 remained of the same composition from 1598 until the 
 adoption of the modern smokeless powders. They were 
 made according to the famous recipe " As, as, six," viz. 
 i part of sulphur, i part of charcoal, and 6 parts of nitre. 
 This corresponds to nitre 75 per cent., and sulphur and 
 charcoal 12*5 per cent. each. The following table gives the 
 composition of a few modern powders made by different 
 countries, but it must be borne in mind that various grades 
 of powder are in use : 
 
 Sporting powder. Blasting powder. 
 
 Country. KNO 3 S C KNO 3 S C 
 
 Great Britain . . . . 75 10 15 65-75 10-20 15 
 
 (Ordinaire . .. 62 20 18 
 
 France] Lente . ..78 10 12 40 30 30 
 
 (Forte ... 72 13 15 
 
 ..78 10 12 65-70 14-20 16 
 
 .. 76 9*4 14*6 60-2 184 2i'4 
 
 Germany 
 Austria 
 
 In the manufacture of gunpowder the ingredients are 
 first ground separately in any suitable form of mill. Char- 
 coal should not be ground for at least a fortnight after 
 burning, as otherwise it may inflame through the absorption 
 of oxygen. Sulphur in grinding requires care, as it is easily 
 electrified, and consequently sulphur mills should be care- 
 fully earthed. Precautions should also be taken against 
 a dust explosion, and the same applies to charcoal. 
 
 The actual manufacture of gunpowder in a modern 
 factory involves seven operations, or eight in the case of 
 moulded powders. The object in the rather elaborate 
 procedure is to obtain a uniform powder, which will not 
 separate and the grains of which will not crumble. 
 
 First Mixing. This is carried out either in a copper 
 ball mill with lignum vitae balls, or in a revolving drum 
 through which passes a shaft carrying eight arms or " flyers." 
 The drum and shaft revolve in opposite directions, the former 
 making 60 revolutions per minute and the latter 120. 
 A uniform mixture is obtained in a few minutes, and the 
 " green " charge then emptied out, sifted, and removed to 
 the incorporating house. 
 
20 
 
 EXPLOSIVES 
 
 FIG. i. Gunpowder Incorporating 
 Machine 
 
 Incorporating or Milling. This was formerly carried 
 out in stamp mills, and these are still in use in some of the 
 smaller continental works, but are being rapidly replaced 
 
 by edge runners. These 
 consist of stone runners 
 acting on a stone bed, or 
 of iron runners on an iron 
 or hard wood bed. Stone 
 must not run on iron, or 
 vice versa, on account of 
 the danger of sparks. The 
 runners weigh 4 to 5 tons 
 each, and are set at dif- 
 ferent distances from the 
 driving shaft, so that they 
 do not run on the same 
 path. Each is provided 
 
 with a scraper to prevent its picking up cake, and with a 
 phosphor bronze or hard wood plough to push the charge 
 into its path. In the best type of incorporating mill the 
 runners do not rest on the 
 bed, but are suspended a 
 short distance above it, 
 and each is capable of 
 an independent vertical 
 movement, so as to allow 
 it to pass over any extra 
 hard lumps without un- 
 due friction (Figs, i and 
 2). In Germany this 
 arrangement is compul- 
 sory if iron runners and 
 an iron bed are used. A 
 
 ., f , . FIG. 2. Gunpowder Incorporating 
 
 charge for incorporation Machine. 
 
 is 50-80 Ibs. and requires 
 
 from 3-8 hours, depending on the nature, of the powder. 
 Moisture, in the form of condensed steam from the drying 
 stoves, is added from time to time so as to maintain a 
 
GUNPOWDER 21 
 
 water content of 3-6 per cent. After incorporation is 
 complete, the charge is removed and roughly broken up 
 by hand, and is then ready for pressing. Any hard in- 
 crustation that remains in the incorporating mill must 
 be thoroughly soaked in water, and then removed with 
 a wooden tool. Incorporation is a somewhat dangerous 
 process, and in this country special safety arrangements 
 must be provided. These consist of a water tank over each 
 machine connected with a large board directly above the 
 incorp orator, so that any movement of the board caused 
 by an explosion wave tips the whole contents of the tank 
 on to the charge and drowns it. All the tanks in each 
 house are interconnected, so that the movement of any 
 board actuates them all. Usually six machines are placed 
 in each house, each machine being separated by a strong 
 partition of masonry. Should the charge in any one mill 
 explode, the force of the explosion wave acting on the board 
 above it tips all the tanks in the building, and so prevents 
 the explosion spreading. 
 
 Pressing. This is carried out in hydraulic presses 
 capable of dealing with about 1000 Ibs. at a time. The 
 presses are charged as follows. A copper or ebonite plate 
 is laid in a horizontal position and surrounded by a light 
 wooden frame about i in. deeper than the thickness of the 
 plate. The tray thus formed is filled with the powder to 
 be pressed, and this carefully smoothed off level with the top 
 of the wooden frame. Another plate is then placed on the 
 top of this, and this surrounded by another wooden frame, 
 and the tray thus formed filled with powder. This is 
 repeated until the full number of plates have been used, 
 usually 20-30. The size of the plates varies in different 
 factories, but they are usually about 2 ft. 4 in. by i ft. 8 in. 
 The wooden frames are then removed and the pile slid into 
 an hydraulic press with upward moving ram (Fig. 3). The 
 pressure applied is about 400 Ibs. per square inch, but it is 
 best measured by watching the movement of the ram and 
 not by gauges. It must be applied slowly, the time occupied 
 being about 2 hours. When pressing is complete the plates 
 
22 
 
 EXPLOSIVES 
 
 14 
 
 are picked off one by one, and the outer edge of each cake 
 
 to a depth of about ij 
 in. cut off and kept sepa- 
 rate from the main bulk. 
 This is done as the peri- 
 phery has not sustained 
 the full pressure. The 
 cuttings are given a 
 short milling and then 
 repressed, whereas the 
 main bulk passes on to 
 the granulating machine. 
 Pressing is a some- 
 what dangerous process, 
 and an explosion is 
 usually very disastrous 
 on account of the large 
 quantity of powder be- 
 ing dealt with. In order 
 to protect the workers 
 all controls should be in 
 a special room sepa- 
 rated from the press by 
 a strong wall, arrange- 
 ments being made for 
 the workman to observe 
 the movement of the 
 ram without entering 
 the press room. 
 
 In this country plates 
 of ebonite are preferred 
 to those of copper, as 
 they are not so easily 
 deformed and transmit 
 thepressure more evenly. 
 On the other hand they 
 are easily electrified, 
 FIG. 3. Gunpowder Press. and Guttmann records 
 
GUNPOWDER 23 
 
 one fatal explosion in which the workman observed a spark 
 4 in. long pass from his hand to the press. Needless to 
 say, presses should be carefully earthed. 
 
 Granulating or Corning. In this process the press 
 
 FIG. 4. Arrangement of Granulating Machine. 
 
24 EXPLOSIVES 
 
 cakes are broken up into grains of the desired size by passing 
 them through a series of three or more pairs of toothed gun- 
 metal rollers revolving towards one another. Between 
 each pair of -rollers are vibrating screens of gun-metal wire 
 which separate the powder into three sizes, viz. oversize, 
 which passes on to the next set of rollers ; right size, which 
 is collected for the next stage ; and undersize, which is 
 collected and remilled and pressed. The construction of 
 a granulating machine is shown diagrammatically in Fig. 4. 
 The rollers should be mounted with spring bearings, so that 
 if they encounter an extra hard piece of cake they can open 
 and let it pass (Fig. 5). Powders made from dogwood 
 
 FIG. 5. Rollers of Granulating Machine. Detail showing Spring 
 Bearings. 
 
 charcoal usually produce a great deal of dust, and are 
 generally given an extra screening (" dusting ") to remove 
 this. 
 
 Glazing. This is carried out in revolving wooden 
 drums, and has the effect of rounding off the grains and 
 improving their appearance. A little graphite is sometimes 
 added when slow-burning powders are being made. 
 
 Stoving or Drying. This is carried out by spreading 
 the powder in thin layers on trays, consisting of a wooden 
 frame with a canvas bottom. Drying is carried out at 
 40 C. by blowing air heated by means of hot water pipes 
 into the building. 
 
 Blending. This consists in mixing several batches so as 
 to obtain a uniform product. 
 
GUNPOWDER 25 
 
 Moulding. Before smokeless powders were introduced 
 suitable slow-burning powders for use with rifled ordnance 
 were prepared by compressing the blended gunpowder 
 into cubes, pyramids, or prisms with from one to eight 
 perforations. The German cocoa powder was especially 
 suited for making moulded powders, as it flowed well in the 
 die. The perforations had the object of obtaining a more 
 constant rate of combustion. These moulded powders are 
 no longer manufactured, but moulded cartridges are used 
 for blasting purposes. These are simply prepared by 
 measuring a definite amount of powder into a die and then 
 compressing it by means of two pistons, one working up- 
 wards and one downwards, actuated by mechanical or 
 hydraulic means. The lower piston carries a plunger which 
 enters a prepared hole in the upper piston, and so leaves a 
 perforation in the cartridge in which the fuze can be inserted. 
 
 Sodium Nitrate Powders. Powders in which the 
 potassium nitrate has been replaced by the cheaper sodium 
 salt are used in gigantic quantities in America. They are 
 somewhat more powerful than ordinary gunpowder, but their 
 chief attraction lies in their cheapness. They suffer from 
 the great disadvantage, however, of being very hygroscopic. 
 They are made in much the same way as ordinary powder, 
 and have an average composition 
 
 Sodium nitrate . . . . 74 
 
 Sulphur . . . . . . 10 
 
 Carbon . . . . . . 16 
 
 Although the annual consumption of this type of powder 
 in the United States amounts to nearly a hundred million 
 pounds (50,000 short tons), it was not used in Great Britain 
 until the outbreak of war in 1914 cut off the supply of potash 
 and compelled the Government to alter the definition of 
 gunpowder, so as to include powders made with sodium 
 nitrate. A very similar powder is much used in Germany 
 under the name " Sprengsalpeter." It is composed of 
 
 Sodium nitrate . . 75 
 Brown coal (lignite) . . . . 15 
 Sulphur 10 
 
26 
 
 EXPLOSIVES 
 
 It is regarded as safer than ordinary powder, and in 
 Germany can be sent in unrestricted amount by goods train. 
 
 " Bobbinite " is a form of gunpowder, and is the favourite 
 coal-getter in this country. It does not pass the Rotherham 
 test, but its use under certain restrictions was specially 
 permitted for a term of five years from January ist, 1914, and 
 by a further Order in Council dated September i8th, 1918, 
 this period has been extended until December 3ist, 1920. 
 It is defined in the Explosives in Coal Mines Order of Sep- 
 tember ist, 1913, as having the composition 
 
 Ingredients. 
 
 ist definition. 
 
 2nd 
 
 definition. 
 
 Potassium Nitrate 
 Charcoal 
 Sulphur 
 
 Maximum, i 
 65 
 i9'5 
 2'5 
 
 Minimum. 
 62 
 
 I? 
 
 Maximum 
 66 
 20*5 
 2'5 
 
 . | Minimum. 
 63 
 18-5 
 
 i'5 
 
 Ammonium Sulphate 
 Copper Sulphate . . 
 Rice or Maize Starch 
 Paraffin Wax 
 Moisture , 
 
 I7 
 
 13 
 
 7 
 2'5 
 
 It is manufactured in moulded pellets, each pellet being 
 coated with paraffin wax and wrapped in brown paper. 
 Bobbinite made according to the first definition must have 
 a density not exceeding 1*42, and according to the second 
 definition not exceeding 1*48. There is no charge limit, 
 and it must not be fired with a detonator. 
 
 Stability, etc. Gunpowder is to be regarded as a very 
 safe explosive. It ignites when heated at 270-300 C., and 
 is fired when struck by a two-kilogram weight falling a 
 distance of 70-100 cm., the powder being confined between 
 hardened steel surfaces. It is completely ruined by water, 
 and powder that has been damp does not regain its full 
 strength on drying. This is due to the moisture dissolving 
 part of the nitrate which crystallizes out on drying, and 
 spoils the intimate mixing of the ingredients so necessary 
 in order to obtain a good explosive. On explosion, it gives 
 about 44 per cent, of gaseous and 56 per cent, of solid 
 products. The gaseous products of explosion are chiefly 
 
GUNPOWDER 27 
 
 nitrogen, carbon dioxide and carbon monoxide, together with 
 small quantities of hydrogen, methane, and sulphuretted 
 hydrogen. The solid products are chiefly composed of 
 carbonate and sulphate of potassium, together with some 
 unburnt sulphur and traces of sulphide, thiocyanate, and 
 nitrate of potassium. 
 
 One gram of powder yields from 250 to 300 cc. of perma- 
 nent gas measured at N.T.P., and evolves from 500 to 700 
 calories. The temperature of explosion is probably about 
 2700 C. 
 
 LITERATURE 
 
 The best account of the history of gunpowder is given by Col. Hime in 
 " Gunpowder and Ammunition." London, 1904. 
 
 A full description of the manufacture of charcoal and sulphur will be 
 found in R. Escales, " Schwartzpulver u. Sprengsalpeter," Leipzig, 1914 ; 
 and in O. Guttmann, " Manufacture of Explosives," London, 1895. 
 
 Information on the products of explosion will be found in the following 
 papers : 
 
 A., 102, 325 ; 109, 53 ; 265, 257. 
 
 Trans. Roy. Soc., 1875, 49. 
 
 Numerous accidents have happened during the manufacture of gun- 
 powder, but the following Special Reports are selected as being particularly 
 instructive: S.R., 160, 165, 177, 179, 181, 189, 190, 202. 
 
SECTION II. EXPLOSIVE COMPOUNDS 
 
 THE number of explosive compounds suitable for industrial 
 use is very limited, owing to the difficulty in combining 
 suitable physical properties with sufficient stability and 
 cheapness of manufacture. Up to the present, with the 
 exception of fulminate of mercury and azide of lead, both 
 of which are largely used for detonators and percussion caps, 
 the only explosive compounds that have been found to 
 fulfil industrial requirements are esters of nitric acid and 
 aromatic nitro-compounds. Of the former the esters of 
 the lower alcohols are too volatile for use, while those of 
 the higher alcohols are too expensive and are deficient in 
 oxygen. Of the polyhydric alcohols glycerine trinitrate 
 is far the most used, as glycerine can be obtained at a 
 moderate price and its trinitrate is easily prepared and is 
 insoluble in water, so that it can be readily washed free 
 from acid. For special purposes the tetranitrate of di- 
 glycerine and the dinitrate of monochlorhydrin are used. 
 In France the use of glycol dinitrate has been proposed, 
 as it has been stated that glycol can be obtained from acety- 
 lene at a price which enables it to compete with glycerine. 
 Tartaric acid forms a dinitrate, but unfortunately it is 
 too unstable for use as an explosive. 
 
 The other polyhydric alcohols are too expensive to 
 allow of their nitrates finding industrial application, although 
 the use of mannitol hexanitrate has been proposed. If these 
 polyhydric alcohols could be obtained at a reasonable price 
 their nitrates would form valuable explosives, as the per- 
 centage of available oxygen increases with the number of 
 carbon atoms carrying a hydroxyl group. Thus, glycol 
 dinitrate contains no available oxygen 
 
EXPLOSIVE COMPOUNDS 29 
 
 CH 2 ONO 2 
 
 | = CO 2 -fN 2 +2H 2 O 
 
 CH 2 ON0 2 
 
 whereas glycerine trinitrate contains 3*5 per cent, and 
 mannitol hexanitrate contains 7-1 per cent. 
 
 2CH 2 ON0 2 .CHON0 2 .CH 2 ON0 2 =6C 
 CH 2 ON0 2 . (CHON0 2 ) 4 .CH 2 ONO 2 =6CO 2 
 
 The sugars form nitric esters, and attempts have been 
 made to use glucose nitrate and sucrose nitrate. Un- 
 fortunately, the nitric esters of the sugars are soluble in 
 water and are hygroscopic and very sensitive. Polyhydric 
 cyclohexanols such as inosite form nitric esters, inosite 
 forming a hexanitrate, but unfortunately inosite and its 
 derivatives are merely chemical curiosities at present. 
 
 Of the fatty hydroxyl compounds of unknown molecular 
 weight cellulose and starch are the best known, and both 
 form nitric esters. Of these the cellulose nitrates are very 
 widely used (guncotton, pyroxylin, collodion cotton), and 
 are usually made from cotton, although wood cellulose is 
 used to some extent. There are mechanical difficulties in 
 nitrating starch and stabilizing the product which have 
 prevented the use of starch nitrates up to the present time. 
 
 Of the nitro-compounds those of the aliphatic series 
 would be useful if they could be obtained more readily, 
 tetranitromethane, for example, containing nearly 24 per 
 cent, of available oxygen 
 
 C(N0 2 ) 4 = C0 2 +2N 2 +30 2 
 
 Unfortunately they are all troublesome and expensive to 
 make, and those having hydrogen atoms attached to the 
 same carbon atom as the nitro-group have the objectionable 
 property of forming unstable salts with metals 
 
 H\ /O 
 CH 3 N0 2 -> >C=N<; 
 
 W X OM 
 
 A large number of aliphatic nitro-compounds also have 
 objectionable toxic properties, especially tetranitromethane. 
 Of the aromatic hydrocarbons benzene forms a dinitro- 
 
30 EXPLOSIVES 
 
 compound easily, and a trinitro-compound with such great 
 difficulty that it is little more than a chemical curiosity. 
 Toluol, on the other hand, forms a trinitro-compound with 
 ease, and the same is the case with xylol. Toluol is also 
 fairly easily nitrated in the side chain (B.P. 6o76 n ), and 
 readily yields nitrophenyl nitromethane. The tetranitro- 
 compound, trinitrophenyl nitromethane, does not, however, 
 seem to have been studied. Of the other aromatic hydro- 
 carbons naphthalene gives a tetranitro-compound, but only 
 with some difficulty, so that the mono-, di- and tri-nitro- 
 compounds only are used. 
 
 The entrance of nitro-groups into the nucleus is facilitated 
 by the presence of amino and hydroxyl groups. Thus, 
 aniline gives a tetranitro-compound with some difficulty, 
 and methyl aniline gives a tetranitro-compound (trinitro- 
 phenylmethyl nitramine), which although somewhat ex- 
 pensive for ordinary purposes, are used for detonators. 
 Diphenylamine gives a hexanitro- compound which has found 
 some application, but unfortunately the nitro-groups confer 
 strongly acidic properties on the imino hydrogen atom. 
 
 Phenol forms a trinitro-compound (picric acid), and so 
 does cresol. Both have been used, but both are, unfortu- 
 nately, strongly acidic. 
 
 No attempts seem to have been made to utilize com- 
 pounds such as nitrobenzyl nitrate, although these should 
 be readily obtained by nitrating benzyl alcohol. Nitric 
 esters are always less stable than nitro- compounds, so that 
 substances containing both groups might be useful for 
 detonators if for no other purpose. 
 
 The aromatic diazo salts are all explosive, but as a rule 
 are too sensitive and too deficient in oxygen to be of any 
 practical value. Attempts have been made, however, to 
 use ^>-nitrodiazobenzene nitrate for detonators, but without 
 much success. 
 
 It should be noted that all aromatic nitro-compounds 
 are very deficient in oxygen. Even the unknown hexa- 
 nitro-benzene would only contain just sufficient oxygen 
 for its complete combustion. Hence, although some of the 
 
EXPLOSIVE COMPOUNDS 31 
 
 nitro-compounds can be detonated alone, they are almost 
 invariably used in conjunction with an oxidizing agent 
 such as ammonium nitrate, although for certain military 
 purposes picric acid and trinitrotoluol are used unmixed with 
 other substances. 
 
 The organic peroxides are also explosives, but are far too 
 unstable to be of any practical value, and the same applies 
 to the ozonides. These latter are rich in oxygen ; benzene 
 ozonide, for example, has the formula C 6 H 6 O 9 , and would 
 be useful were it not for their extreme instability. 
 
 Of the inorganic explosive compounds, lead azide is 
 used to some extent for detonators as a substitute for 
 mercury fulminate. The chlorates being formed endo- 
 thermically from the chloride and oxygen are mildly ex- 
 plosive, and are used in some explosive mixtures, e.g. 
 Cheddite, and in fireworks. Ammonium nitrate can be 
 detonated with great difficulty, and is used to a very large 
 extent. Ammonium perchlorate can also be detonated, and 
 is an ingredient of some explosives. Ammonium bichromate 
 is also an explosive, and although somewhat expensive 
 and dangerous, is used in one or two French powders. 
 The capacity of all these ammonium salts to explode is due 
 to the acid radical oxidizing the ammonium radical. 
 
 NITROGLYCERINE 
 
 The term "nitroglycerine" is chemically incorrect, the 
 explosive having the formula CH 2 (ONO 2 )CH(ONO 2 )CH 2 - 
 (ONO 2 ), and being therefore glycerine trinitrate. The term 
 "nitroglycerine" is, however, invariably used commercially, 
 and in practice is frequently abbreviated to N.G. 
 
 Glycerine for nitration should be almost pufep^Good 
 dynamite glycerine has only a pale amber colgur, and its 
 specific gravity should be not less than 1260. jit should be 
 almost free from ash and contain only slight traces of fatty 
 acids, aldehydes (acrolein), unsaponified fat, chlorides, sul- 
 phates, etc. It should contain no sugar or glucose, although 
 these are sometimes present as adulterants. For the nitra- 
 tion only dearsenicated or non- arsenical acids should be used. 
 
32 EXPLOSIVES 
 
 Nitration is invariably carried out with a mixture of nitric 
 and sulphuric acid, and nowadays it is customary to make 
 up the mixed acids with oleum, so that the mixture is^almost 
 anhydrous, but contains no free sulphuric anhydride. } The 
 use of oleum is not essential, but is a matter of convenience. 
 The composition of the mixed acid varies in different 
 factories, but the following are all in use with satisfactory 
 results : 
 
 HNO 3 .. ..40 46-5 41*5 
 
 H 2 S0 4 .. .. 58-4 52-5 58-0 
 
 H 2 O .. ..1-6 1-4 -5 
 
 6 parts of mixed acid are used to every part of 
 glycerine. 
 
 In some countries nitration is carried out in cast-iron 
 jacketed vessels provided with a mechanical agitator. 
 These are prohibited in almost all European countries, 
 lead vessels with cooling coils being used and agitation being 
 effected by compressed air. }ln Great Britain nitration must 
 be carried on at a temperature not exceeding 22 C., but in 
 other countries the limit is 25 C., or even 30 C. The 
 temperature is observed by means of two thermometers, 
 one dipping into the charge and one suspended above the 
 charge and registering the temperature of the " gas," i.e. the 
 air which is being forced through the charge for agitating it. 
 
 Nitrating House. Two types of nitrator are in general 
 use, but the older type introduced by Nobel (Fig. 6) is being 
 rapidly displaced by the nitrator- separator of Thomson, 
 Nathan, and Rintoul. *\ In the older type of plant the charge 
 of acid is run in from the measuring tank, the air agitation 
 and cooling water turned on and the glycerine then sprayed 
 in, the rate at which the glycerine is added being regulated 
 so as to maintain a temperature of 22 C. During the 
 nitration the workman watches the fumes through the 
 window A, any appearance of red fumes being a sign of 
 danger. During the nitration the run-off cock, B, is tempo- 
 rarily connected by means of a movable lead gutter with a 
 large lead-lined drowning tank outside the building, so that 
 
EXPLOSIVE COMPOUNDS 
 
 33 
 
 should the charge get out of control it can be at once drowned. 
 The provision of a drowning tank is only a precautionary 
 
 
 L i 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ^ 
 
 o 
 
 
 ^* 
 
 o 
 
 
 o 
 
 
 
 
 
 **. 
 
 ^ 
 
 *N 
 
 *. 
 
 ^ 
 
 o 
 
 
 o 
 
 
 o 
 
 o 
 
 
 
 
 
 
 o 
 
 o 
 
 
 
 
 
 
 
 o 
 
 o 
 
 
 
 
 o 
 
 o 
 
 o 
 
 o 
 
 
 o 
 
 
 o 
 
 
 
 
 
 
 
 
 o 
 
 o 
 
 o 
 
 
 Q 
 
 
 o 
 
 o 
 
 
 o 
 
 o 
 
 o 
 
 o 
 
 o 
 
 
 Q 
 
 
 o 
 
 o 
 
 
 o 
 
 o 
 
 o 
 
 o 
 
 o 
 
 
 o 
 
 
 o 
 
 o 
 
 
 o 
 
 o 
 
 o 
 
 o 
 
 
 
 
 <~* 
 
 
 ^ 
 
 o 
 
 
 
 
 o 
 
 o 
 
 
 
 
 
 
 ^ 
 
 
 o 
 
 o 
 
 
 o 
 
 o 
 
 o 
 
 o 
 
 o 
 
 
 o 
 
 
 ^ 
 
 o 
 
 
 
 
 o 
 
 o 
 
 o 
 
 o 
 
 
 ^J 
 
 
 o 
 
 o 
 
 
 o 
 
 
 
 o 
 
 o 
 
 o 
 
 
 o 
 
 
 o 
 
 o 
 
 
 o 
 
 
 
 o 
 
 o 
 
 o 
 
 
 o 
 
 
 Q 
 
 
 
 
 o 
 
 o 
 
 o 
 
 o 
 
 o 
 
 
 o 
 
 
 o 
 
 o 
 
 
 o 
 
 
 
 o 
 
 o 
 
 o 
 
 
 o 
 
 
 o 
 
 
 
 
 o 
 
 
 
 
 
 o 
 
 \p 
 
 
 Q 
 
 
 o 
 
 o 
 
 
 o 
 
 o 
 
 o 
 
 o 
 
 L^ 
 
 S 
 
 a 
 
 ==: 
 
 
 
 
 o 
 
 o 
 
 o 
 
 T. 
 
 FIG. 6. Glycerine Nitrator (Old Type). 
 
34 EXPLOSIVES 
 
 measure, as if a suitable quality of glycerine is used and 
 ordinary care taken in nitration no trouble is experienced. 
 When all the glycerine has been added the charge is cooled 
 to 15 C., and then run down a lead-lined gutter to the 
 separating house. The size of charge nitrated varies in 
 different factories from 300 to 1500 Ibs. of glycerine. The 
 time taken depends largely on the temperature of the 
 cooling water, and, unless a refrigerating plant is in use, 
 may vary from half an hour in winter to two hours or more 
 in summer. When nitration is finished for the day the 
 nitrators are carefully washed out and allowed to stand 
 overnight with water pressure on the coils. This latter 
 is a precautionary measure to detect any small leakage. 
 The nitrators require to be dismantled about every two 
 months for examination and repairs. 
 
 (Separating House. The charge from the nitrating 
 house is received in lead tanks (Fig. 7) and allowed to 
 stand, so that the specifically lighter nitroglycerine rises to 
 the surface. When separation is complete the spent acid 
 is run off from the bottom cock, A, until the line of separa- 
 tion is seen through the window B. The nitroglycerine is 
 then run into the pre-wash tanks and roughly washed with 
 water or dilute soda solution. Being heavier than water, 
 it forms the lower layer, and after pre-washing is run down a 
 gutter to the wash house or filter house. These gutters 
 must be j acketed with warm water in winter time to prevent 
 the nitroglycerine freezing.; 
 
 The waste acid from the separating house is run away to 
 the after-separating house, where it is allowed to stand for 
 two or three days in order that separation may be complete. 
 The oil that separates is skimmed off or collected by dis- 
 placement, and carried back to the pre-wash tank in gutta- 
 percha buckets. The waste acid is pumped to the acid 
 department, where it is denitrated with steam and then 
 concentrated. As a rule it contains 10-12 percent, of 
 nitric acid. To prevent any further separation of nitro- 
 glycerine it is advisable to dilute it with one or two per cent, 
 of water, and not to allow the waste acid in the store tanks 
 
EXPLOSIVE COMPOUNDS 
 
 35 
 
 inf 
 
 to become too chilled in cold weather. In any case it should 
 be denitrated as soon as possible. 
 
 Both separating and after-separating tanks must be 
 provided with thermometers and with compressed air 
 agitators and cooling coils, so that the contents can be 
 mixed and cooled in case of any undue rise in temperature 
 due to decomposition setting in. They must also be pro- 
 vided with drowning tanks 
 placed outside the building. 
 
 The necessity for after- 
 separation can be avoided 
 by adding 3-5 per cent, of 
 water to the waste acid. 
 This dissolves the globules 
 of nitroglycerine and pre- 
 vents the formation of further 
 quantities from unchanged 
 glycerine or glycerine sul- 
 phate. 
 
 In order that separation 
 may take place in a reason- 
 able time, the mixed acid 
 used for nitration should be 
 allowed to stand for several 
 days before use in order that 
 suspended matter, such as 
 flue dust, iron sulphate, lead 
 sulphate, etc., may settle 
 OUt. The addition of Sodium FlG . 7 . Separator for Nitroglycerine, 
 fluoride to destroy finely 
 
 divided silica has been patented (A.P. 804,817), and it is 
 claimed that a great saving of time is effected by its use, 
 only about 'ooi per cent, being required. On the other 
 hand, patents have been taken out for hastening separation 
 by the addition of siliceous matter such as china clay 
 (E.P. i4,586 12 . Pat. Anm. 38,595 (1911))- 
 
 *wash and Filter House. The construction of wash 
 tanks varies somewhat in different factories, but the best 
 
EXPLOSIVES 
 
 type is that shown in Fig. 8, as this avoids the use of cocks, 
 The oil is agitated with the water or soda solution by 
 means of compressed air and then allowed to settle. The 
 supernatant water is then drawn off by means of the soft 
 rubber hose, which is slowly lowered. The oil is left in the 
 tank and again agitated with water or soda solution, and 
 again separated as before. When finally neutral the oil 
 is drawn off by lowering the outside soft rubber hose. In 
 
 FIG. 8. Wash Tank for Nitroglycerine. 
 
 another type of wash tank the lower layer of oil is separated 
 from the upper aqueous layer, and forced into another tank 
 on the same level by adding water. 
 
 The number of washings required is usually nine, viz. 
 three water washings and one soda washing in the pre-wash 
 tanks, and three soda washings and two water washings in 
 the wash house, but washing must be continued until a 
 satisfactory heat test (over ten minutes) is obtained (Section 
 IX.). The strength of the soda solution used is usually 
 about 3 per cent., and all water must be at about 22 C. 
 It is a good plan to do the final washing with distilled water, 
 
EXPLOSIVE COMPOUNDS 37 
 
 an ample supply of which is usually available at no cost 
 from the condensed steam used in the various drying stoves. 
 Otherwise softened water must be used. 
 
 All wash waters both from the pre-wash tanks and from 
 the wash house are led to the " deposit of washings/' 
 They are here made to circulate slowly through labyrinths 
 of lead in such a manner that they pass alternately over 
 and under the partitions. This causes them to deposit any 
 globules of oil that they may hold in suspension. The oil 
 thus deposited is collected from time to time, and carried 
 back in gutta-percha buckets to the wash house. 
 
 After washing until neutral the nitroglycerine is filtered 
 through sponges sewn up in flannel bags, in order to remove 
 flocculent matter and suspended water. It is then stored 
 in lead tanks in carefully warmed houses, but is almost 
 invariably used within 36 hours of being made. 
 
 Nitrator - Separator. This form of nitrator was 
 patented by Thomson, Nathan, and Rintoul (E.P. I5,983 01 , 
 3020 3 ), and is described in the Journal of the Society of 
 Chemical Industry, 1908, page 193. The nitrator is shown 
 in Figs. 9 and 10, and the charge is worked as follows. 
 The mixed acid is introduced and nitration carried out 
 as described on page 32. After nitration, however, instead 
 of running the whole charge into a separate vessel for 
 separation, it is allowed to stand for a few minutes, and 
 waste acid from a previous charge then slowly introduced 
 through the pipe and cock C. The nitroglycerine over- 
 flows by B into the pre-wash tank situated in the same 
 building. The line of demarcation of the mixed acid and 
 oil is watched through the window A, and the rate of 
 entrance of spent acid governed so that this remains station- 
 ary, the nitroglycerine overflowing to the wash tank as 
 rapidly as it separates. When separation is complete the 
 nitrator is left standing full of acid until required for further 
 use. Any further nitroglycerine that has separated is then 
 removed and the waste acid run out by the cock D to the 
 after-separators, if these are used, but when the nitrator- 
 separator is used it is customary to add sufficient water to 
 
EXPLOSIVES 
 
 
 
 O 
 
 o 
 
 O 
 
 o 
 o 
 o 
 o 
 o 
 o 
 o 
 
 fcTWbl 
 oooo 
 
 
 oooo 
 
 
 oooo 
 
 
 oooo 
 
 
 oooo 
 
 
 oooo 
 
 
 oooo 
 
 
 oooo 
 
 
 oooo 
 
 
 oooo 
 
 
 O O.O 
 
 * 
 
 _^--* 
 
 FIG. 9. Nitta tor-Separator. 
 
EXPLOSIVE COMPOUNDS 
 
 39 
 
 the spent acid to prevent any further separation of nitro- 
 glycerine, and thus avoid after-separation. This type of 
 nitrator has now been adopted by all the leading works in 
 this country, as it has the following advantages : 
 
 (1) No cocks are used, so that all danger of an explosion 
 being caused by the friction of turning a cock is avoided. 
 
 (2) The nitroglycerine is removed as soon as separated, 
 so that the duration of 
 
 time in which it is in con- 
 tact with acid is reduced 
 to a minimum. 
 
 (3) Repairs and renewals 
 are much les^. The older 
 type of nitrator has to be 
 washed-out every day after 
 use, and the dilution of the 
 acid which remains adher- 
 ing to the lead sets up 
 serious corrosion. It is for 
 this reason that the nitrator 
 has to be dismantled every 
 two months, although many 
 authorities state that the 
 corrosion is due to fume. 
 For a matter of fact the 
 lead of the older type of 
 nitrator is exposed to fume 
 
 no more than the lead of the nitrator-separator. The 
 nitrator-separator, on the contrary, remains full of acid 
 when not in use, so that corrosion caused by the dilution 
 of residual acid is avoided. The first nitrator-separator 
 used at Waltham Abbey ran for 2f years without being 
 dismantled, and was then found to be in perfectly good 
 condition, no repairs of any sort being required. 
 
 Nitroglycerine is a colourless oil which freezes at 13*3 C., 
 but exhibits the phenomenon of super-cooling to a con- 
 siderable extent. When in the frozen state it is less easily 
 detonated, and in small quantities is less sensitive to shock, 
 
 FIG. 10. Nitra tor-Separator. (Plan 
 showing acid inlets and outlets.) 
 
40 EXPLOSIVES 
 
 although in bulk it is probably more sensitive when frozen 
 than when liquid. 
 
 Nitroglycerine has a marked physiological eff ect, dilating 
 the blood-vessels and causing violent headache and sickness. 
 It is rapidly absorbed through the skin and the majority 
 of workers suffer severely at first, although they usually 
 become immune after a few days. The best remedy for 
 N.G. headache is strong black coffee or aspirin. 
 
 Nitroglycerine is very sensitive to shock and is exploded 
 by a kilogram weight falling 4 cm., the nitroglycerine being 
 confined between hardened steel surfaces. 
 
 On heating, nitroglycerine decomposes slowly below 
 100 C. and explodes at about 150 C. 
 
 On the manufacturing scale 100 Ibs. of dynamite glycerine 
 yields from 230 to 235 Ibs. of nitroglycerine. The cost of 
 manufacture in 1914 was about 6d. per Ib. The cost of 
 manufacture at two Government factories during the period 
 January-June, 1918, was just under 100 per ton, the 
 glycerine accounting for about 40 and the nitric acid for 
 about 45 (C.T.J., 1919, p. 139). 
 
 Attempts have been made to use dinitroglycerine mixed 
 with glycerine in order to obtain an explosive that does not 
 freeze so readily, but not much success has been achieved, 
 as the dinitric ester is soluble in water and forms cryohydrates 
 (D.R.P. I7,575 n , 181,385). Much greater success has met 
 the use of dinitrochlorhydrin. This is made by nitrating 
 monochlorhydrin in exactly the same way that glycerine 
 .is nitrated. As, however, it is almost solely used in 
 conjunction with nitroglycerine, it is more usual to nitrate a 
 mixture of glycerine and monochlorhydrin (S.5., 1906, 227). 
 
 Dinitrochlorhydrin boils with slight decomposition at 
 190 C., and, although readily detonated by fulminate, is 
 so insensitive to shock that it is not exploded by a 2 kg. 
 weight falling 2 metres. It can only be frozen with great 
 difficulty, and remains liquid at 30 C. 
 
 Non-freezing oils have also been obtained by nitrating 
 mixtures of glycerine and diglycerine (CH 2 OHCHOHCH 2 )2o 
 this latter being formed by heating glycerine to 290 C. 
 
EXPLOSIVE COMPOUNDS 41 
 
 with or without a trace of alkali (5.5., 1906, 231 ; E.P. 9572 08 ) 
 or at 250 C. in a current of inert gas (B.P. 24,608 10 ). 
 
 The use of dinitroacetyl glycerine and dinitroformin 
 are mentioned in D.R.P. 209, 943. 
 
 Finally, dinitroglycol has been used in France. It is a 
 more powerful explosive than nitroglycerine, and it is 
 claimed that it can be manufactured at a lower cost (P.5., 
 16, 72). It does not freeze above 20 C. 
 
 Interesting results have been obtained from a study of 
 the solubility of nitroglycerine in sulphuric acid of various 
 strengths, and in sulphuric acid containing nitric acid. 
 The solubility is due to two causes, viz. the true solubility 
 of nitroglycerine as such and the solubility due to the de- 
 composition of the explosive. With sulphuric acid alone 
 the solubility rises slowly with increasing strength of acid 
 until an acid strength of about 50 per cent, is reached. 
 Then the rise in solubility becomes very rapid, the curve 
 being almost vertical in the region where H 2 SO 4 =90 per cent. 
 Between 50 and 90 per cent, great instability is exhibited, 
 and the nitroglycerine is liable to undergo spontaneous 
 decomposition with uncontrollable violence, so that manu- 
 facturing operations must be so adjusted that nitroglycerine 
 is not brought into contact with acids of this strength. 
 
 With sulphuric acid containing water and nitric acid 
 in the proportion i : 1*1 the case is somewhat different, 
 and instability is most marked when the mixture contains 
 under 60 per cent, of sulphuric acid, i.e. contains more than 
 40 per cent, of nitric acid of 52 per cent, strength. 
 
 The curve of total nitroglycerine absorbed in acids con- 
 taining varying percentages of sulphuric acid shows a very 
 marked peak where H 2 SO 4 =5o, and becomes almost 
 vertical above the point H 2 SO 4 =8o. The amount of 
 nitroglycerine dissolved as such also becomes very steep 
 when H 2 SO 4 =8o, but the peak where H 2 SO 4 =50 is only 
 very slight, showing that the solubility is chiefly due to 
 decomposition. These values are important both as a 
 guide to suitable acid mixtures for obtaining a good yield 
 and also as showing that nitroglycerine may become 
 
42 EXPLOSIVES 
 
 dangerous through violent decomposition when in contact 
 with acids of certain strengths. 
 
 Glycerine is invariably obtained from natural sources, 
 viz. from fatty oils, and is a by-product from the soap 
 industry. Over 50 per cent, of the world's production 
 of glycerine is used in the manufacture of explosives, the 
 remainder being used chiefly for medicinal purposes. In 
 view of the extremely simple chemical structure of the 
 glycerine molecule, it is curious that no synthesis has yet 
 been devised that is even remotely suited for use on a large 
 scale. Proposals have been made to carry out the synthesis 
 by condensing acetylene with methane in the presence of 
 suitable catalysts, and then converting the butylene thus 
 obtained into glycerine by treatment with chlorine and 
 alakli 
 
 CH CH 2 CH 2 C1 CH 2 OH 
 
 CH CH -> CHC1 -> CHOH 
 
 II I I 
 
 CH 2 CH 2 C1 CH 2 OH 
 
 but no success has been achieved, as the reactions are not 
 so simple as they appear. 
 
 Glycerine is always formed as a by-product in the 
 fermentation of sugar by yeast, and is probably formed by 
 the auto- digestion of the yeast cell. A process based on 
 fermentation would therefore not seem to be impossible, 
 and the United States Government claim that they have 
 evolved such a process and have proved it to be feasible 
 on a manufacturing scale. No details have been made 
 public, but the process has been communicated to the 
 Allied Governments. 
 
 Prior to the war the price of " dynamite glycerine " was 
 variable, but in the neighbourhood of 100 per ton, about 
 iof^. per lb., and although this would no doubt come down 
 considerably with increased supplies, still the demand is 
 so great that a sufficient margin would remain to allow a 
 good profit on a synthetic process should one be discovered. 
 
 Possibly glycerine may be 'displaced in the future to 
 
EXPLOSIVE COMPOUNDS 43 
 
 some extent by glycol, as this seems somewhat easier to obtain 
 by synthetic means 
 
 CH CH 2 CH 2 Hlg CH 2 OH 
 
 III -> II -> I -> I 
 
 CH CH 2 CH 2 Hlg CH 2 OH 
 
 The best results are obtained by using bromine, the 
 yields under these circumstances being said to be almost 
 theoretical. The capital cost, however, is very heavy, and 
 the unavoidable mechanical loss which takes place in all 
 manufacturing operations is a serious item when an ex- 
 pensive material such as bromine is involved, so that should 
 glycol be manufactured extensively by this method it 
 would be necessary to use chlorine. This, owing to its 
 lower atomic weight, has the further advantage of requiring 
 considerably less alkali for the final hydrolysis. Dinitro- 
 glycol is quite suitable for the manufacture of explosives, 
 and its use is actually authorized in France (see page 41). 
 It contains exactly the right amount of oxygen for its com- 
 plete oxidation 
 
 CH 2 ONO 2 
 
 | 
 
 CH 2 ONO 2 
 
 NITROCELLULOSE 
 
 Cellulose has the formula (C 6 H 10 O 5 ) n , the molecular 
 weight being quite unknown, although there is no doubt that 
 the molecule is of great complexity. The structure is also 
 quite unknown, but as nitric esters containing 13*96 per 
 cent, of nitrogen can be obtained it is probable that there 
 are three hydroxyl groups reckoned in the simple mole- 
 cule C 6 H 10 O 5 , the trinitric ester of which would contain 
 14-14 per cent, of nitrogen. It may be said at once that 
 these esters with high nitrogen content are unstable and 
 of no commercial value, as it is almost impossible to obtain 
 stable nitrocelluloses containing much over 13-1 per cent, of 
 nitrogen. 
 
 Some authorities attempt to classify nitrocelluloses by 
 ascribing the imaginary formula C 24 H 40 O 20 to cellulose, but 
 
44 EXPLOSIVES 
 
 the cellulose esters as at present known are undoubtedly 
 mixtures, and it is much more scientific to characterize 
 them by their nitrogen content and by their solubility in 
 ether-alcohol (one volume ether and two volumes alcohol). 
 Officially in this country guncotton is defined as nitrocellulose 
 containing over 12*3 per cent, of nitrogen, and of which not 
 more than 15 per cent, is soluble in alcohol-ether. Esters 
 containing less than 12-3 per cent, of nitrogen, and more or 
 less completely soluble, are known as collodion or pyroxylin. 
 In factories guncotton is generally known as G.C. and collo- 
 dion cotton as C.C., whereas N.C. denotes nitrocelluloses in 
 general. 
 
 The whole theory and practice of the preparation of 
 nitrocellulose rests on an empirical basis, owing to the 
 complete absence of any knowledge of the structure of the 
 cellulose molecule. Undoubtedly all forms of cellulose are 
 colloidal in nature, but to what extent the substance known 
 as cellulose represents a pure compound we have no means 
 of ascertaining. Probably there are numerous forms of 
 cellulose, but speculation on this line must remain guess- 
 work in our present state of knowledge. In the manu- 
 facture of nitrocelluloses the chief raw materials are cotton 
 waste, used chiefly for making guncotton and collodions 
 for varnish or celluloid, cotton wadding used for collodion 
 for blasting explosives, paper used for various purposes 
 such as celluloid, and purified wood or wood pulp used for 
 certain smokeless powders. It is probable that great 
 progress has been made in the use of wood in Germany 
 owing to their military requirements and the failure of the 
 cotton supply through the Allied blockade, but no information 
 on this point is as yet forthcoming. 
 
 Cotton waste used for making guncotton undergoes 
 several processes of purification before it is fit for nitration. 
 These consist in extracting with solvents and scouring with 
 soda to remove oil, washing and bleaching. This preliminary 
 treatment is carried out by the suppliers and not by the explo- 
 sives works. As delivered, it should contain under 8 per 
 cent, of moisture and not more than '4 per cent, of oil. It 
 
EXPLOSIVE COMPOUNDS 45 
 
 should not be harsh to the touch or friable (over bleaching) 
 and should only produce slight reduction when boiled with 
 Fehling's solution (oxy cellulose) . It is picked over by 
 hand to remove bits of string, nails, etc., and then run 
 through a teasing machine to loosen knots, dust being at 
 the same time removed by a fan. After drying, to reduce 
 the moisture to i per cent, or less, it is ready for nitration. 
 
 Guncotton. The mixed acid used for manufacturing 
 guncotton in this country (13 per cent, of nitrogen) has the 
 composition 
 
 HN0 3 23 
 
 H 2 SO 4 70 
 
 H 2 7 
 
 In the old Abel process the cotton in lots of ij Ibs. was 
 dipped into the mixed acid contained in cast-iron pans. 
 After five minutes it was lifted out, squeezed by hand on 
 an iron grating and then placed in stoneware pots set in a 
 trough of running water. Nitration proceeded for 12 hours, 
 after which time the excess of acid was wrung out as far 
 as possible in hydro-extractors and the guncotton drowned 
 quickly in a large volume of cold water .; This process^was 
 later modified into the direct dipping process, in which the 
 cotton is digested with the mixed acid for from 8 to 24 hours 
 at 20 C. in water-cooled iron pans, the ratio of acid to 
 cotton being 6 : i. Both these process^, which are still in 
 use on the Continent and in some collodion works in this 
 country, were wasteful in acid and injurious to the workmen 
 owing to the fumes./ In addition, a great deal of labour 
 was involved and charges fuming off were frequent. Indeed 
 in the Abel process a drop of perspiration falling on to a 
 charge when digesting was frequently sufficient to cause it 
 to fume off. These disadvantages led to the introduction 
 of the displacement process by Nathan and Thomson (B.P. 
 8278 03 . A.E., 1906, 77), by which great economies in 
 material and labour were effected, all fumes avoided, and 
 a superior product obtained. The process has been very 
 generally adopted by explosives works in this country. jmd 
 
4 6 
 
 EXPLOSIVES 
 
 is coming into extensive use on the Continent and in 
 America. Up to the present it has not been generally 
 used for the manufacture of collodion, but by selecting a 
 suitable mixed acid there would seem no good reason why 
 it should not be used for this purpose, and no doubt the 
 extensive guncotton plants that have been erected for war 
 
 FIG. ii. Cotton Nitrating Pan (Displacement Process). 
 
 purposes will be diverted in this direction, the collodion 
 being used for medicinal and photographic purposes, arti- 
 ficial silk, celluloid, varnish, aeroplane dope, etc. 
 
 The nitrator is shown in Fig. n, and consists of a shallow 
 earthenware pan, 3 ft. 6 in. diameter, 10 in. deep at the sides 
 and 12 in. deep at the run-off cock at the centre. It has a 
 false bottom of perforated stoneware segments. The run-off 
 cock is connected with the mixed acid store tanks, waste 
 acid tanks, and with a drain, and four nitrators are usually 
 
EXPLOSIVE COMPOUNDS 47 
 
 grouped together so as to be worked as one unit. In carrying 
 out a nitration mixed acid (650 Ibs.) is allowed to run into 
 each pan, and then 20 Ibs. of cotton waste added in single 
 handfuls and quickly pushed under the surface of the acid 
 by means of an aluminium fork. During this process the 
 pan is covered by a light portable aluminium hood connected 
 with a fume pipe so that all acid fume is drawn off. When 
 the whole of the cotton has been added it is covered with 
 loose perforated stoneware segments, on to the surface of 
 which a layer of chilled water at 5 C. is run slowly. This seals 
 the plant and prevents any escape of fume: Nitration takes 
 2 J hours, and the fuming off of a charge is almost unknown. 
 When nitration is complete the waste acid is run off at the 
 bottom at the rate of about one gallon per minute, and at the 
 same time and at the same speed cold water is run on to the 
 top perforated plates. Water being a great deal lighter 
 than the waste acid, the line of demarcation between them 
 remains fairly sharp and about 500 Ibs. of waste acid are 
 recovered in a state fit for revivifying with nitric acid and 
 oleum. This portion of the waste acid has the com- 
 position 
 
 HNO 3 18 
 
 H 2 S0 4 727 
 
 H 2 .. .. ..9*3 
 
 the rest is somewhat weaker 
 
 HN0 3 18 
 
 H 2 S0 4 61 
 
 H 2 O 21 
 
 and is denitrated and concentrated. Displacement takes 
 about three hours, and the loss of acid is only about I per 
 cent, of the weight of the guncotton made. The yield of 
 guncotton is about 170 per cent. Up to the present these 
 displacement nitrators have always been constructed of the 
 dimensions given, as stoneware vessels of large size are 
 expensive and not very satisfactory. There would seem to 
 be no reason, however, why larger vessels should not be * 
 built of cast iron lined with acid-proof stoneware segments, 
 
4 8 
 
 EXPLOSIVES 
 
 of enamelled iron or of ferro-silicon. Naked cast iron or lead 
 cannot be used, as, although they would be unattacked 
 during nitration, they would be seriously affected by the dilu- 
 tion of the acid during the later stages of the displacement. 
 The centrifugal nitrating process is used extensively in 
 Germany and also to some extent in this country, especially 
 for the mauufacture of collodion cotton for blasting explo- 
 sives. In this case nitration is carried on in a centrifugal 
 
 FIG. 12. Nitrating Centrifugal. 
 
 machine so arranged that the rotation of the basket causes 
 the acid to circulate through the cotton. A simple type of 
 nitrating centrifugal is shown diagrammatically in Fig. 12, 
 the circulation of the acid being indicated by the arrows. 
 It will be noticed that the vertical spindle passes through 
 the central conical part of the outer case by a sleeve situated 
 well above the acid level, and is attached to the basket at 
 the top of the central perforated cone. During nitration 
 the machine rotates very slowly, but when nitration is 
 complete the excess of acid is run off and the machine speeded 
 
EXPLOSIVE COMPOUNDS 49 
 
 up so as to wring out the superfluous acid. This wringing, 
 however, must not be carried too far or there will be con- 
 siderable danger of the charge fuming off, and this applies 
 to all processes in which the excess of acid is removed by 
 whizzing. As a rule the acid content of the nitrated cotton 
 is not reduced below 50-60 per cent, before drowning. The 
 charge for a centrifugal machine is 15-25 Ibs. of cotton and 
 750-1250 Ibs. mixed acid. 
 
 The composition of the acid used for making collodion 
 depends on the duration and temperature of nitration, 
 process of nitration employed, and on the nature of the 
 product required. The viscosity of the solutions of the 
 collodion depends very largely on the temperature at which 
 nitration takes place. For blasting explosives high viscosity 
 is required, so that nitration is carried out at or about the 
 ordinary temperature. A suitable mixed acid for this 
 purpose is 
 
 HN0 3 25-0 
 
 H 2 S0 4 .. ... 57-5 
 
 H 2 17-5 
 
 These collodions usually contain about 12 per cent, of 
 nitrogen. 
 
 For smokeless powders the viscosity is much less im- 
 portant, nitrogen content, which is a measure of power, 
 being the important point. No reliable information is 
 available as to the acids used for nitrating cellulose for 
 sporting powders, but the United States military powder 
 is made with an acid of this composition 
 
 HNO 3 21-5 
 
 H 2 S0 4 6 3 -5 
 
 H 2 O . . . . . . . . 15-0 
 
 Nitration is carried out by the displacement process at 
 a temperature of 30 C. and takes from i to 2 \ hours. Seven 
 hundred pounds of acid are used for 20 Ibs. of cotton, and 
 the product contains about 12*7 per cent, of nitrogen and is 
 almost completely soluble in alcohol-ether. A similar nitro- 
 cellulose is used by the French Army. s The yield is 155 per 
 T. 4 
 
50 EXPLOSIVES 
 
 cent. For varnishes and photographic films low viscosity 
 is required, and hence nitration is carried out at a higher 
 temperature, although this usually entails a lower yield. 
 A good low grade pyroxylin can be made with an acid 
 
 HNO 3 17 
 
 H 2 S0 4 55 
 
 H 2 O 28 
 
 nitrating for 15 minutes at 45-55 C. and using 50 parts 
 of acid to each part of cotton. The product contains about 
 12*4 per cent, of nitrogen, and the yield is about 130 per cent. 
 Washing. After a preliminary wash to remove the 
 greater part of the acid the nitro-cotton is boiled several 
 times with water. This boiling is carried out in pitch pine 
 vats with a run-off cock below a perforated false bottom, 
 heating being effected by direct steam. The number and 
 duration of the boilings varies at different factories, but 
 good results are obtained by two boils of twelve hours each, 
 followed by five of four hours each and then three of two 
 hours each, the object of the long boils at first being to 
 hydrolyse unstable esters. Collodion cotton for blasting 
 explosives will not stand such drastic treatment, as boiling 
 spoils the viscosity of the jelly formed with 'nitroglycerine. 
 Hence it is usual only to wash it several times with water 
 near the boiling point A Nitro-cotton cannot be rendered 
 stable by boiling alone, as acid gets into the hollow fibres 
 and cannot be removed by this process. The only way 
 to remove this is by the pulping process introduced 
 by Abel. After boiling, therefore, the cotton is removed 
 to pulpers and made to circulate between rapidly re- 
 volving knives until reduced to a fine pulp. The con- 
 struction of a pulper is shown diagrammatically in Fig. 13. 
 again the process must not be carried too far with 
 collodion intended for blasting explosives, or the gelatinizing 
 properties will be spoilt.j A large amount of water is used 
 during the pulping operation, and when pulping is complete 
 the creamy liquid is pumped into tanks at the top of the 
 building and then made to flow along long wooden gutters 
 
EXPLOSIVE COMPOUNDS 51 
 
 lined with woolly blanket material. The woolly material 
 collects a large amount of grit, and particles of iron are 
 collected by electro-magnets placed at intervals. The pulp 
 then enters a large timber vat, known as a poacher, fitted 
 with a wooden paddle, where it is allowed to settle and the 
 supernatant milky water drawn off. The pulp is then stirred 
 up with more water and again allowed to settle. It is usually 
 given three washes in the poacher, and is then removed 
 to hydro extractors and as much of the water as possible 
 extracted. As obtained from the extractors it contains 25-35 
 per cent, of moisture, and in this state is perfectly safe. 
 
 FIG. 13. Pulping Machine for Nitrocellulose. 
 
 Dry nitrocellulose, however, is very easily inflamed, and all 
 operations with it must be carried out in danger buildings. 
 The stoves are light timber structures surrounded by earth 
 mounds and certain movable trays on which the nitro- 
 cellulose is spread. These trays may be constructed of 
 light timber frames with canvas bottoms, but fine copper 
 gauze or zinc sheet is much better. They are about 2 in. 
 deep and must be earthed, as dry nitrocellulose is very easily 
 electrified. Heating is brought about by blowing in warm 
 air, but the temperature of the stove must not exceed 40 C. 
 To avoid, nitrocellulose dust being blown about, some firms 
 compress the wet cotton into slabs by means of hydraulic 
 presses before drying. This system has many advantages, 
 
52 EXPLOSIVES 
 
 although drying takes somewhat longer. Only moderate 
 pressure is used in forming the slabs so that they are easily 
 broken up when dry. In any case, as dry nitrocellulose is 
 much more dangerous when warm, the stoves must not be 
 unloaded until they have cooled. 
 
 If the nitrocellulose is going to be used for making 
 smokeless powder by gelatinization with alcohol and ether, 
 or if it is going to be used for making a solution in which 
 alcohol is employed as a solvent, there is no need to dry it. 
 Under these circumstances it is packed into" cylinders and 
 alcohol then forced through it in a downward direction. 
 The first runnings are pure water, followed by dilute spirit 
 which is afterwards rectified. The last runnings are stronger 
 spirit, and are used for the first washing of the next batch. 
 The process is very similar in principle to the displacement 
 process of nitrating, and is generally known as "alcoholizing." 
 The average cost of manufacturing guncotton (13 per 
 cent, nitrogen) at three Government factories during the 
 period January-June, 1918, was ^137*8 per long ton, about 
 is. 3^. per lb., this amount being made up as follows : cotton 
 waste ^50*6, nitric acid 44*5, labour, etc., 36*6, sulphuric 
 acid 6-1 (C.T.J., 1919, p. 139). 
 
 NlTROAROMATIC COMPOUNDS 
 
 Dinitrobenzole. Although mononitrobenzole cannot be 
 exploded either by a blow or by a fulminate detonator, the 
 dinitro-compound is sufficiently unstable to be exploded by 
 either of these means, although only with difficulty, explosion 
 being brought about by a two-kilogram weight falling 200 
 cm., the dinitrobenzole being confined between hardened 
 steel surfaces. It is made by nitrating nitrobenzole with 
 mixed acids at 100 C., its manufacture being fully described 
 in the volume on " Coal Tar Dyes and Intermediates " in 
 this series. The pure product melts at 91 C., but the 
 commercial article at 8o-85 C. 
 
 Dinitrotoluol and Trinitrotoluol. Both these are used 
 extensively in the manufacture of explosives, especially the 
 
EXPLOSIVE COMPOUNDS 53 
 
 latter. Trinitrotoluol (T.N.T.) is exploded by a two-kilo- 
 gram weight falling 108 cm,, and is fairly readily exploded 
 by fulminate of mercury. In the pure state it is used for 
 naval and military purposes in torpedo charges and to a lesser 
 extent in shells. It finds its chief application, however, when 
 mixed with nitrates, especially ammonium nitrate, for shell 
 filling (amatol) and as a blasting explosive./^ Although T.N.T. 
 can be obtained from toluol in one step this process is very 
 extravagant in acid, and consequently the manufacture is 
 invariably carried out in two or three steps; depending to 
 some extent on the quality of product desired and on what 
 other products are being manufactured simultaneously. 
 In spite of the enormous output of T.N.T. for war purposes, 
 it is doubtful if the most economical process for use under 
 peace conditions has yet been evolved. This is due to 
 the shortage and excessive price of sulphuric acid having 
 compelled manufacturers to work more with a view to 
 economy of acid and oleum than with a view to minimum 
 cost of production. Under present circumstances only 
 about 2 Ibs. of T.N.T. are obtained from i Ib. of toluol, this 
 corresponding to a yield of about 77 per cent, of theory. 
 With increased supplies of oleum available it will probably 
 be found more economical to complete the final nitration 
 with a stronger acid and a correspondingly lower temperature, 
 as by this means better yields will be obtained. 
 
 In carrying out the nitration in two steps, toluol is first 
 nitrated to mononitrotoluol * (M.N.T.) and this then further 
 nitrated to T.N.T. \ The composition of the mixed acid 
 used for the final nitration depends on what acids are avail- 
 able for mixing, but both the following give good results. 
 The latter*, however, usually requires a small amount of 
 oleum 
 
 HNO 3 16 18 
 
 H 2 SO 4 78 78 
 
 H 2 .. ..6 4 
 
 The amount of mixed acid taken is such that it contains 
 
 * For details seeBarnett, "Coal Tar Dyes an<l Intermediates," in 
 series, p. 16, 
 
54 
 
 EXPLOSIVES 
 
 if Ibs. of nitric acid for every pound of M.N.T. to be nitrated. 
 The size of the charge varies in different works, but by using 
 
 FIG. 14. Nitrator for Nitroaromatic Compounds 
 
 12,000 Ibs. of mixed acid about 2000 Ibs. of T.N.T. can be 
 made, and this can be worked conveniently in a nitrator of 
 
EXPLOSIVE COMPOUNDS 55 
 
 1000 gals, working capacity. These nitrators are made of cast 
 iron with internal lead coils for heating and cooling, and are 
 provided with an efficient mechanical agitator (Fig. 14). In 
 working a charge the mixed acid is first run in and then the 
 M.N.T. During the addition of the latter the temperature is 
 not allowed to rise above 50 C. When all the M.N.T. has been 
 added the temperature is raised at the rate of about i C. 
 every two minutes. At about 70 C. there is considerable 
 evolution of heat, and care must be taken to check this by 
 turning water into the coils. The charge is generally cooked 
 for i hour at 100 C., and the temperature then slowly raised 
 to 120 C. and maintained at this point until nitration is 
 complete. This generally takes about J hour, and is ascer- 
 tained by taking a sample and determining the setting 
 point. The charge is then cooled to 85 C., and about f gallon 
 of water for every hundred pounds of mixed acid used run 
 in. The object of this is to reduce the solubility of the 
 T.N.T. in the spent acid (D.R.P. 254,754). During the 
 addition of the water the heating up of the charge must be 
 carefully checked and the temperature not allowed to rise 
 above 100 C. The charge is then again cooled to 85 C., 
 the agitator stopped and separation allowed to take place 
 for an hour. The lower layer of spent acid is then drawn off 
 and the supernatant T.N.T. run off into a tank of boiling 
 water for washing. It must be washed free of acid, and on 
 no account must any alkali be used, as if so the T.N.T. 
 becomes very sensitive. Usually four washes suffice to 
 remove all the acid, after which the T.N.T. is dried by heating 
 to 105 C. and then either cast in shallow trays or flaked 
 on an internally water-cooled revolving drum. Instead of 
 adding water to the charge after nitration, dilute sulphuric 
 acid obtained from the vitriol concentrating plant can be 
 conveniently used. 
 
 The waste acid from the trinitration contains consider- 
 able quantities of T.N.T. in solution. This can be recovered 
 by agitating it at 80 C. with the M.N.T. to be used for 
 the next charge, in which case any nitric acid present is 
 used up with the formation of a small quantity of dinitro- 
 
56 EXPLOSIVES 
 
 toluol. In this case the final waste acid will contain about 
 3 per cent, of nitrous acid, and is denitrated and concentrated 
 for further use. In some works, however, the T.N.T. spent 
 acid is revivified by the addition of nitric acid and then 
 used for making M.N.T. The T.N.T. made by this process 
 has a setting point of about 76 C. 
 
 The three-stage process is somewhat more complicated, 
 but is frequently used by those works which make m- 
 toluylenediamine. As before, the toluol is first nitrated to 
 M.N.T. This is then converted into the dinitro-compound by 
 treatment with an acid of the composition 
 
 HNO 3 30 
 
 H 2 S0 4 64 
 
 H 2 6 
 
 nitration being carried on at 60 C. and the charge finally 
 cooked at 80 C. The dinitro-compound can then be 
 directly nitrated to T.N.T., or it can be roughly separated 
 into fractions of high and low setting point. This is done 
 by draining in on fine mesh wire gauze trays at a temperature 
 near its setting point, when most of the lower melting fractions 
 run off, the last being got rid of by whizzing. If the residue 
 is then nitrated, T.N.T. with a setting point of 80 C. is 
 obtained. The oil can also be nitrated, and for this purpose 
 Bscales recommends an acid of the composition 
 
 HN0 3 10-2 
 
 H 2 SO 4 82-2 
 
 H 2 7-6 
 
 allowing a ratio of acid to dinitro-compound of 2-8:1. 
 The setting point of the T.N.T. thus obtained is 72-74 C. 
 Those qualities of T.N.T. that have low setting points are 
 obviously mixtures of various isomeric trinitrotoluenes with 
 some dinitrotoluene. 
 
 For the manufacture of blasting explosives the setting 
 point of T.N.T. is not a matter of importance, but for deto- 
 nating fuze and certain military purposes in which the 
 explosive is to be used unmixed with nitrate it is necessary 
 to employ almost pure sym- trinitrotoluene (M.P. 81-9) in 
 
EXPLOSIVE COMPOUNDS 57 
 
 order to secure complete detonation. For this purpose the 
 crude T.N.T. can be crystallized from alcohol containing 
 20 per cent, of benzole, from onitrotoluol (B.P. I7,oo3 14 ) or 
 from sulphuric acid monohydrate (D.R.P. 237,738). The 
 setting point can also be raised by washing with alcohol or 
 boiling sodium sulphite solution, or by allowing the crude 
 product to drain on wire gauze in stoves maintained at a 
 temperature approximating to its setting point. 
 
 When organic solvents are employed in its purification 
 the residue left on distillation consists of a mixture of di- 
 and tri-nitrotoluols. On nitration it yields a product which 
 remains liquid at the ordinary temperature and is much 
 used for manufacturing blasting explosives, especially non- 
 freezing jellies, as it mixes very readily with nitroglycerine. 
 The first liquid product of this nature was manufactured 
 by J. W. Iveitch & Co., of Huddersfield, and sold as " liquid 
 trinitrotoluol." The method of manufacture is a trade 
 secret, and although other firms have produced similar 
 liquids, they have not the same capacity for remaining fluid 
 and usually become pasty on standing. Trinitrotoluol, 
 like all other aromatic nitro-compounds, has a decidedly 
 toxic effect on those working with it. The preliminary 
 symptom is a rash which appears chiefly on the arms and 
 may be followed by toxic jaundice, several fatalities having 
 occurred from this cause. The trouble is most marked during 
 the summer months, and some individuals are much more 
 sensitive than others. Those that are sensitive should not 
 be allowed to continue working, and any worker who shows 
 signs of rash should at once be given a change of work 
 until these symptoms have subsided. In Great Britain there 
 is a statutory obligation to provide baths, special clothes, and 
 rubber gloves for those handling T.N.T. and kindred com- 
 pounds. As regards rubber gloves, the author's experience is 
 that they do more harm than good, as the interior gets soiled 
 when taking off, and thereafter the sweating of the hands 
 that they induce causes T.N.T. to be more readily absorbed 
 through the skin. Closely woven cotton gloves or chamois 
 leather gloves are more satisfactory, as they can be washed 
 
58 EXPLOSIVES 
 
 after each day's work if necessary. Probably the best 
 preventive methods will be found to lie in ample ventila- 
 tion, prevention of dust, and the artificial cooling of the 
 work-rooms during warm weather. When possible, workers 
 should be given a change of employment at regular intervals. 
 Under the provisions of the Factory Act they must be 
 medically examined at frequent intervals. 
 
 Trinitrotoluol is known under various trade names such 
 as trotyl, tritol, triolite, but most usually by the initials 
 T.N.T. Until recently it was specially exempted from treat- 
 ment as an explosive by an Order in Council made under 
 the Explosives Act. The numerous accidents that occurred 
 during the war have led to the withdrawal of this exemp- 
 tion, and trinitrotoluol must now be manufactured under 
 " danger " conditions. The average cost of manufacture of 
 crude T.N.T. (setting point j6-j8 C.) at six Government 
 factories during the period January- June, 1918, was 110 
 per ton, the average consumption of toluol being -491 ton 
 per ton of T.N.T. These figures must, however, be accepted 
 with some reserve, for whereas toluol, acid, and nitrate 
 seem to be reckoned in long tons (2240 Ibs.) it is not stated 
 whether T.N.T. is reckoned in long tons or in short tons 
 (2000 Ibs.), the latter being almost invariably employed 
 when dealing with explosives (C.T.J., 1919, p. 117). 
 
 Picric Acid (Trinitrophenol). Under the names of 
 Ivyddite, Melinite, etc., 'picric acid was for many years the 
 standard shell-filling used by almost all the Powers, but 
 during recent years it has largely been replaced by the 
 cheaper, safer, and more convenient T.N.T. The great 
 disadvantage of picric acid lies in its acidic character and its 
 capacity for forming highly sensitive salts, especially with 
 the heavy metals, the lead salt being the most dangerous. 
 Picric acid cannot safely be mixed with nitrates such as 
 ammonium nitrate, as owing to its strongly acid character 
 a certain amount of free nitric acid would be liberated 
 should the explosive become damp. Its use is confined 
 to military purposes, and it will probably be completely 
 displaced by T.N.T. at an early date. 
 
'EXPLOSIVE COMPOUNDS 59 
 
 Picric acid was originally manufactured by direct nitra- 
 tion of phenol, but this process is never carried on now, 
 although in 1900 a process for nitrating phenol in paraffin 
 was described (B.P. 16,628 ) and good results claimed. 
 The usual process is based on the sulphonation of phenol 
 to the monosulphonic acid with subsequent nitration and 
 simultaneous replacement of the sulphonic acid group. The 
 sulphonation is carried out with 4 parts of sulphuric acid of 
 98 per cent, strength at ioo-io5. Another four parts of 
 sulphuric acid are then added and the melt run into a nitrator 
 and cooled to 20 C. The nitrator may be made of cast 
 iron, but enamelled iron is preferable. Nitration is brought 
 about by the slow addition of mixed acid composed of equal 
 parts of concentrated sulphuric acid and nitric acid of 61 per 
 cent, strength. At first the temperature is kept below 
 40 C., but after half the mixed acid has been added the 
 temperature is slowly increased to 70-8o C. The charge 
 is then run into a series of stoneware pots and diluted with 
 an equal volume of water. On cooling the picric acid 
 crystallizes out and is filtered off, washed, whizzed, and 
 finally dried at a low temperature, usually 35 C. 
 
 A more modern process avoids the use of phenol, chlor- 
 benzole being used as the starting out point. This is first 
 nitrated to the dinitro-compound, which on boiling with 
 soda gives dinitrophenol.* This latter is readily nitrated 
 to picric acid, but details of the nitrating process are not 
 available at present. This is probably the best process, and 
 is likely to replace the older process if picric acid continues 
 to find use as an explosive. The cost of manufacture of 
 picric acid at H.M. Factory, Greetland, during the period 
 January-June, 1918, was 1847 P er l n S ton > a ^out is. 8d. 
 per Ib. The process used was the nitration of phenol 
 sulphonic acid (C.T.J., 1919, p. 162). 
 
 Picric acid melts at 122-6 C. 
 
 Tetranitroaniline. This was first obtained by Flursheim 
 in 1910 by nitrating w-nitraniline or certain near derivatives 
 
 * For details see Barnett, "Coal Tar Dyes and Intermediates," in this 
 series, pages 18 and 66. 
 
60 EXPLOSIVES 
 
 of w-nitraniline (E.P. 3224 10 ). The patentee describes the 
 nitration of w-nitraniline as follows : " One part of meta- 
 nitro- aniline is dissolved in 36 parts of strong sulphuric 
 acid (either concentrated acid or monohydrated or fuming 
 acid) at the ordinary temperature or with external cooling, 
 2j parts of sodium nitrate are then added, and the mass is 
 allowed to remain at the ordinary temperature or at a lower 
 or only slightly higher temperature for several days." He 
 also states that the nitration can be carried out by heating 
 to 70 C. and then finally, after the reaction has subsided, 
 to 100 C. It will be seen that a very excessive amount of 
 sulphuric acid is required, and the cost of the process could 
 only be kept within reasonable bounds by using the spent 
 acid for other purposes. The compound has been used for 
 detonator compositions, but tetranitromethyl aniline has 
 been found more suitable for this purpose. 
 
 Tetranitromethyl Aniline. This is really trinitro- 
 
 methyl phenylnitramine CH 3 N< 6 ^Q , and is known 
 
 usually as tetryl or tetralite. It is manufactured by nitrating 
 dimethyl aniline, one methyl group being simultaneously 
 oxidized. The process is described by Escales (" Nitro- 
 sprengstoffe ") as follows : 
 
 One hundred kilos, of dimethyl aniline are slowly added 
 to 1000 kilos, of well-cooled concentrated sulphuric acid of 
 97-98 per cent, strength. A pale brown coloured solution 
 is obtained, but it must not be too dark and must remain 
 transparent. As the solution decomposes on standing the 
 nitration should be effected as soon as possible. This is 
 brought about by running the solution slowly into 530 kilos, 
 of nitric acid of 87 per cent, strength which has previously 
 been warmed to 40 C. The strength of the nitric acid is 
 important, as if a stronger acid is used the product separates 
 in large crystals which are difficult to wash. During the 
 addition of the dimethyl aniline solution the temperature 
 at first is not allowed to exceed 44 C., but after two- thirds 
 has been added it is allowed to rise to 55 C., and when the 
 addition is complete the charge is cooked for two hours at 
 
EXPLOSIVE COMPOUNDS 61 
 
 this temperature and is then cooled and allowed to stand 
 overnight. The nitro-compound crystallizes out and the 
 majority of the spent acid can be run off. On the average 
 this has the composition 
 
 HNO 3 11-05 
 
 H 2 SO 4 74-04 
 
 H 2 O 12-09 
 
 NO 2 2-58 
 
 Nitro-compounds . . . . -24 
 
 The nitro-compound is then collected on niters, and after 
 washing first with dilute sulphuric acid and then with water 
 is dried. The yield of the crude product is 210 kg., but it is 
 unstable and should be purified at once by recrystallization 
 from benzole. The benzole is recovered from the liquors by 
 distillation, and to avoid danger of the residue exploding it is 
 best to add a large volume of water before commencing the 
 distillation. These residues are quite valueless and are burnt. 
 
 Tetryl jtnelts at I29-I30 C. and is very poisonous. Up 
 to the present it has only found application for detonators 
 or shell fuzes, but its use as a shell filling or as an ingredient 
 in blasting explosives has been proposed. During the period 
 January-June, 1918, 145*6 tons of tetryl were manufactured 
 at H.M. Factory, Queensferry, at the average cost of 297*4 
 per (short?) ton, the consumption of dimethyl aniline being 
 546 (long ?) tons per (short ?) ton of tetryl produced (C.T.J., 
 1919, p. 162). 
 
 Pentanitromethyl aniline (tetranitromethylphenyl nitra- 
 mine) has been described (B.P. 3907 10 ), but does not seem 
 to have found any application. 
 
 MISCELLANEOUS COMPOUNDS 
 
 The following compounds have been proposed for use as 
 explosives or as ingredients in the manufacture of explosives, 
 and although not in general use they are worthy of short 
 notice with a view to possible future developments : 
 
 Nitromethane, CH 3 N0 2 . A stable liquid boiling un- 
 decomposed at 101 C. It is readily obtained by the action 
 of sodium nitrite on chloracetic acid (B., 42, 3438), and owing 
 
62 EXPLOSIVES 
 
 to its low molecular weight would be useful as a means of 
 lowering the freezing point of nitroglycerine. Its high cost 
 precludes its use at present, but experiments carried out by 
 the author indicate that the yields could be greatly improved. 
 
 Tetranitromethane C(N0 2 ) 4 . This freezes at 13 C. 
 and boils undecomposed at 126 C. Owing to its large 
 content of oxygen it would be a most valuable ingredient. 
 Several processes have been described for manufacturing 
 it by the action of nitric acid or nitric anhydride on acetic 
 anhydride (D.R.P. 211,198, 211,199, 224,057) or on nitro- 
 aromatic compounds such as picric acid (D.R.P. 184,229), 
 but it is doubtful if any of them are yet technically possible. 
 Tetranitromethane is very toxic. 
 
 Nitro-sugars. These have been studied with a view to 
 their use in detonators. As a class they are soluble in water 
 and hence their isolation is troublesome. They can be 
 purified by crystallization from alcohol, but are too sensitive 
 and unstable for use (B., 1898, 68-90). 
 
 Nitro-mannitol. Mannitol gives a hexanitrate which 
 is insoluble in water and can be crystallized from alcohol. 
 It melts at 112 C. and is comparatively stable. Several 
 attempts have been made to employ it in detonators, but with- 
 out success so far. It is, however, worthy of further attention. 
 
 Nitro-starch. Many attempts have been made to 
 employ nitro-starch as an ingredient in explosive mixtures, 
 but up to the present no marked success has been obtained. 
 Starch is troublesome to nitrate, as it balls together, and the 
 only satisfactory method is to dissolve it in nitric acid and 
 then spray the solution into sulphuric acid or mixed acid. 
 So far it has been found impossible to stabilize the product 
 on an industrial scale, but as a stable nitro-starch with 
 14*04 per cent, of nitrogen has been obtained in the laboratory 
 by elaborate treatment with organic solvents it must be 
 concluded that the instability is due to impurities. Nitro- 
 starch is soluble in nitroglycerine, but does not gelatinize it. 
 For further information see S.S., 1910, 82. 
 
 Hexanitrodiphenylamine. This has been used in 
 Germany as a charge for floating mines. It is made b}^ the 
 
EXPLOSIVE COMPOUNDS 63 
 
 nitration of diphenylamine or by condensing chlordinitro- 
 benzole with aniline and then nitrating the dinitrodiphenyl- 
 amine thus obtained. It has the objectionable property of 
 being an acid and is extremely poisonous, so that its use is 
 not likely to become general (S.S., 1910, 15 ; 1913, 205, 231 ; 
 D.R.P. 86,295). 
 
 Hexanitrodiphenyl Sulphide (Picryl sulphide). This 
 can be obtained by the action of sodium thiosulphate on 
 picryl chloride (B.P. i8,353 13 ). It is very stable, non- 
 poisonous, and does not stain yellow. It is decidedly more 
 powerful than picric acid and about 10 per cent, stronger 
 than trinitrotoluol. It has been proposed for use in 
 detonators and as a shell-filling. In connection with the 
 latter, and in view of the use of gas in warfare by Germany, 
 it is interesting to note that the patentee (Carl Hartmann, 
 Schlebusch) claims that " the free sulphurous acid contained 
 in the fumes on the detonation of a striking shell renders the 
 continuance in a closed space, such as casemates, holds of 
 vessels, etc., impossible " (E.P. i8,354 13 ) . Unfortunately the 
 compound is expensive to produce, as picryl chloride can only 
 be obtained by the nitration of chlorbenzole by using excessive 
 amounts of acid. This might be remedied to some extent 
 by fortifying the waste acid from the trinitration and then 
 using it for mono- or di-nitration. The corresponding sulphone 
 is obtained by oxidation with nitric acid (D.R.P. 269,826). 
 
 Hexanitrodiphenyl Oxide. The symmetrical com- 
 pound (picric anhydride) has not been described, but an un- 
 symmetrical compound is obtained by condensing i-chlor- 
 2-4-dinitro-benzole with w-nitro-phenol and then nitrating 
 (D.R.P. 281,053). It is a stable compound of about the 
 same power as picric acid. 
 
 Hexanitro-oxanilide. This can be obtained by nitrat- 
 ing oxanilide (F.P. 391,106). It is a stable compound 
 melting at 295-300 C., and is about as powerful as tri- 
 nitrotoluol. Its temperature of explosion is rather low, and 
 hence it may find useful application as an ingredient of 
 permitted explosives for use in fiery mines. 
 
 Hexanitrodiphenyl. A stable explosive obtained by 
 
64 EXPLOSIVES 
 
 the action of copper powder on picryl chloride. It is too 
 expensive for general use, but may find application for 
 detonators (F.P. i8,333 14 ). 
 
 Spent Acids. The manufacture and concentration of 
 nitric and sulphuric acids is treated in another volume in 
 this series,* but although the recovery of spent acids from 
 nitration operations is carried out by similar means it is 
 accompanied by certain difficulties, due chiefly to the organic 
 impurities present. The recovery of spent acids from the 
 manufacture of aliphatic nitric esters is the most simple, as 
 these acids are fairly readily burnt clean. In dealing with 
 nitrocellulose waste acid the strongest portion is revivified 
 for further use by the addition of oleum and nitric 
 acid, and the nitric acid then recovered from the remainder 
 by distillation. The residual sulphuric acid still contains 
 2-3 per cent, of nitrous acid which cannot be removed by 
 distillation and it is denitrated by steam, the nitrous acid 
 being recovered as nitric acid in towers. The removal of 
 this nitrous acid is absolutely necessary, not only on the 
 grounds of economy, but also to avoid trouble with the 
 lead work of the concentration plant. The denitrated acid 
 is finally concentrated, this being almost invariably done 
 in this country in the Kessler plant, although the Gaillard 
 tower is in use by at least one big firm, and cascade plants 
 are also used. 
 
 Nitroglycerine waste acids are not distilled, but are 
 denitrated with steam and then concentrated. lyike nitro- 
 cellulose waste acids, this is easily accomplished and is usually 
 carried out in the Kessler plant. 
 
 Spent acids from aromatic nitrations are much more 
 difficult to deal with owing to the more stable nature of 
 the organic impurities which they contain. In addition 
 the separation of the nitro-compounds is slow and in fact 
 usually continues for several days or even weeks, although 
 the amount that separates is usually comparatively small 
 and hardly worth recovering. The acids usually contain 
 little or no nitric acid, but from 3 to 4 per cent, of nitrous 
 * Partington, "The Alkali Industry," in this series. 
 
EXPLOSIVE COMPOUNDS 65 
 
 acid, and hence denitration must be brought about by 
 steam. A certain proportion of the organic matter is 
 volatilized by this means, and as it becomes further nitrated 
 it sets at a comparatively high temperature and causes 
 great trouble in the condensers and towers. This is best 
 remedied by using vety capacious condensers and keeping 
 the part of them nearest the towers at about 5o-6o C., but 
 facilities must be provided for cleaning out solid matter, 
 and steam laid on so that the whole plant can be heated up 
 should signs of a stoppage appear. The denitrated acid 
 still contains a large quantity of organic matter, and this 
 tends to separate more readily owing to the greater dilution 
 of the acid. Provision must therefore be made for collecting 
 any that separates, as otherwise it may catch fire in the 
 concentration plant. In any case a considerable amount 
 always distils off during concentration, and hence all fume 
 lines and scrubbers must be run hot to prevent stoppages. 
 To reduce troubles of this nature to a minimum denitration 
 is sometimes carried out with highly superheated steam, 
 about 500 C., and this is undoubtedly the best way, as the 
 high temperature rids the acid more or less of its volatile 
 constituents and not only saves trouble in the concen- 
 trating plant, but also makes concentration more easy by 
 reducing the amount of organic matter. 
 
 Owing to the stable nature of the organic matter in the 
 sulphuric acid, concentration requires a far higher tempera- 
 ture than is the case with the acids from nitroglycerine and 
 nitrocellulose. For this reason the cascade type of plant is 
 almost invariably employed, and it is usually finished up with 
 a cast-iron pan or pans. These can be fired from the same 
 furnace as the rest of the cascade, but are much better fired 
 separately. The " fume " from these pans is at a high tempe- 
 rature and is sometimes used for denitrating the feed acid. 
 
 If the denitration has been carried out at a high tempera- 
 ture so that the denitrated acid is comparatively poor in 
 organic matter, concentration can be carried out in the 
 Kessler plant, but the heavy sludge is very apt to settle 
 out in the plateaux and block up the culottes, so that 
 T- 5 
 
66 EXPLOSIVES 
 
 the modified Kessler plants (such as the A.G.D. Concentrator) 
 would probably give better results. 
 
 This sludge is chiefly sulphate of iron which has been 
 picked up from the iron nitrators or from the waste acid store 
 tanks when these are made of steel. It is extremely trouble- 
 some, as it settles out in various parts of the plant and causes 
 stoppages, and settles out in the basins of the cascade and 
 causes them to crack. It cannot be avoided, but can- be 
 reduced somewhat by using lead in preference to iron, 
 especially when handling waste acid. Certainly this results 
 in the formation of lead sulphate, but the amount is much 
 less and it is somewhat less troublesome to deal with. 
 
 LITERATURE 
 
 NITROGLYCERINE 
 
 A description of some of the older methods of manufacture will be 
 found in " Manufacture of Explosives," O. Guttmann, London, 1905. 
 An account of the modern displacement process will be found in A.E., 
 1906, p. 90 ; J. S.C.I., 1908, 193. 
 
 Accidents in the manufacture of nitroglycerine have been numerous, 
 and the following Special Reports are very instructive : S.R., 150, 156, 161. 
 162, 164, 167, 180, 200. 
 
 NITROCELLULOSE 
 
 A great deal of information on nitrocellulose for both explosive and 
 other purposes will be found in " The Nitrocellulose Industry," by E. C. 
 Worden, 2 vols., London, 1911. 
 
 The displacement process is described in detail in A.E., 1906, p. 77, 
 whereas nitrating centrifuges are described and fully illustrated in 5.5., 
 1910, pp. 352, 413, 434, 458, 478. 
 
 The Abel process is described in detail in the Journal of the Society of 
 Chemical Industry, 1909, 180. The following Special Reports on accidents 
 will repay study : S.R., 166, 169, 206, 207. 
 
 TRINITROTOLUOL 
 
 The following references deal with its stability, use as an explosive, and 
 toxic properties : A.E., 1914, 68 ; 5.5., 1912, 425 ; 1913, 97, 213 ; 1914, 
 239, 37 8 45, 432 ; P.S., xvi., 40, 97, 213. 
 
 The majority of accidents that have been due to T.N.T. have taken 
 place during the war and reports are not yet available. The following, 
 however, will be found of interest : 5.5., 1907, 333, 413, 416 ; 1908, 298 ; 
 1909, 213; A.R., 1903,26. 
 
 PICRIC ACID 
 
 The best description of the manufacture of picric acid will be found in 
 Metallurgical and Chemical Engineering, 1915, p. 686. 
 For accidents, see S.R., 81, 139. 
 
 TETRANITROANILINE AND TETRYL 
 
 A.E., 21, 21. 36; 24, 137, 144; 25, 38. 
 5.5., 1913, 185. 
 
SECTION III. SMOKELESS PROPELLANTS 
 
 PROPEU.ANTS FOR RIFLED ARMS. 
 
 THE properties of a propellant for use with rifled arms are 
 somewhat different from those required by smooth-bore 
 arms, as the former require a slow-burning powder that 
 will impart a "push " to the projectile, whereas shot guns 
 call for a more rapidly burning explosive, the effect of which 
 is more akin to a blow. The projectile in a rifled arm 
 engages closely with the rifling, copper bands (" gas checks " 
 or " driving bands ") being provided for this purpose in 
 the case of steel shell, so that comparatively little gas can 
 escape before the projectile leaves the muzzle. If a rapidly 
 burning powder is used combustion will be complete before 
 the projectile has travelled any appreciable distance, and 
 excessive and dangerous pressure will be developed. This 
 pressure, moreover, will fall off rapidly, so that in addition 
 only low muzzle velocity will be attained. If on the other 
 hand a suitable slow -burning powder is employed combustion 
 will take place during the whole travel of the projectile, so 
 that a steady pressure will be maintained and high muzzle 
 velocity without excessive pressure will be achieved. To 
 maintain an even pressure until the moment that the pro- 
 jectile leaves the muzzle is usually mechanically impossible, 
 as it is impossible to construct most guns with the same 
 thickness of metal at the muzzle as at the breach, but the 
 longer the gun the slower burning must be the propellant. 
 In rifled arms the maximum pressure developed is usually 
 about 15 tons per square inch, whereas in shot guns it is 
 only about 2-4 tons. 
 
 Before the introduction of smokeless powder, slowness 
 01 burning was attained by the use of moulded powders, 
 
68 EXPLOSIVES 
 
 some of the pellets being as much as ij in. long. The re- 
 duction of surface achieved by moulding the powders caused 
 them to burn much more slowly, as combustion takes place 
 only on the surface. Naturally as the powder burns the 
 pellets become smaller, and consequently the surface less. 
 In order to compensate for this and maintain a steady rate 
 of combustion, they were made with one or more perfora- 
 tions. With these powders, although the external surface 
 decreased during combustion, the internal surface increased, 
 so that by choosing a suitable number of perforations a very 
 steady rate of combustion could be and was obtained. 
 These moulded powders have now gone quite out of use, 
 but the same principle is applied to smokeless powders, viz. 
 the rate of combustion is controlled by the size of the powder. 
 The following qualities are required of an ideal smokeless 
 powder : 
 
 (i) Regular Ballistics. Regular ballistics are only 
 attained with a regular rate of burning. For this reason 
 the powder must not be so brittle that it breaks up during 
 transport or combustion, and it must not be porous so that 
 combustion can spread through the mass without being 
 confined to the surface. With tubular or perforated powders 
 mechanical strength is necessary, as the gas pressure inside 
 the tubes is greater than that outside, and consequently 
 if the material is mechanically weak the tubes will burst. 
 The effective surface of flake powders may become reduced 
 owing to the flakes lying face to face, and with a view to 
 preventing this some flake powders are made with ridges 
 or knobs. Finally, the powder must contain little or no 
 volatile matter that can evaporate during storage and 
 thereby alter the composition of the explosive, and it should 
 not be affected by climatic conditions, e.g. must not be 
 subject .to freezing. 
 
 (2) Stability. This is very necessary in the case of 
 military powders which may be kept in storage for many 
 years before use. The most stable powders are usually 
 those which are least porus, as porosity frequently leads to 
 instability through oxidation. They are also less hygroscopic. 
 
SMOKELESS PROPELLANTS 69 
 
 (3) Absence of Fouling. The powder must produce a 
 minimum of fouling, and this should be of such a nature 
 that it is easily removed. The products of combustion 
 should contain no substance capable of corroding the barrel. 
 
 (4) Absence of Smoke. This can only be achieved by 
 powders which on combustion give only products which 
 are gaseous at the ordinary temperature. All powders 
 produce water on combustion, and in very cold weather 
 this is sometimes condensed to a mist. Any powder con- 
 taining a nitrate produces more or less smoke owing to 
 solid matter, as ammonium nitrate is the only nitrate giving 
 gaseous decomposition products, and this cannot be used 
 owing to its deliquescent nature. 
 
 (5) Absence of Fume. The products of combustion 
 should not contain any poisonous gas. Carbon monoxide 
 is almost always present, but is not dangerous under the 
 conditions under which propellants are used. The muzzle 
 gases of propellants containing nitroglycerine, however, 
 frequently contain a certain amount of this compound, and 
 in consequence give rise to " gun headache." This is 
 particularly the case with heavy ordnance. 
 
 (6) Absence of Erosion. Erosion is due to two causes, 
 viz. the scouring action of solid particles and the tempera- 
 ture attained by the interior surface of the arm. The 
 erosion caused by black powder is due almost solely to the 
 scouring effect of the solid products of combustion, whereas 
 in the case of modern smokeless powders erosion is due 
 to the surface of the metal being fused and then washed 
 away by the outrush of the gases, and consequently to 
 avoid erosion the temperature of combustion must be kept 
 down. 
 
 (7) Absence of Back-flash. Back-flash is due to the 
 products of combustion being rich in carbon monoxide and 
 this firing when the breach is opened. It is especially 
 dangerous in artillery, and many accidents have been caused 
 by its firing other charges lying in the turret. It can only 
 be avoided by using a powder containing sufficient oxygen 
 to burn all the carbon to carbon dioxide. 
 
70 EXPLOSIVES 
 
 (8) Absence of Flash. Flash is objected to in military 
 explosives, as it reveals the position of the gun when night 
 firing is taking place. It can be remedied by the addition 
 of neutral salts, but these produce smoke which is obj ection- 
 able by day. 
 
 (9) High Power and Density. The greater the power of 
 an explosive, the less is the weight required to produce a 
 given effect. This is important from a military point of 
 view, as it saves transport and means less weight for the 
 soldier to carry. A high density means that less room is 
 required for storage, and is specially desirable for naval 
 purposes where magazine accommodation is limited. 
 
 (10) Insensitiveness to Shock. This is also more important 
 for military than for sporting purposes. For use under 
 service conditions a high degree of insensitiveness is very 
 desirable, as the explosive should not explode when struck, 
 for example, by a rifle bullet. 
 
 (n) Quickness. The powder should not show any 
 tendency to hang fire when fired with a suitable cap and 
 primer. 
 
 Smokeless propellants for rifled arms can be divided 
 into two classes, viz. those consisting of nitroglycerine and 
 nitrocellulose with or without the addition of small quantities 
 of other materials to act as stabilizers or deterrents, and 
 nitrocellulose powders, containing no nitroglycerine, but 
 consisting of nitrocellulose with or without the addition 
 of stabilizers, deterrents, or nitrates. Although both 
 classes contain nitrocellulose, the latter are known as nitro- 
 cellulose powders and the former as nitroglycerine powders. 
 The stabilizers are compounds which are capable of taking 
 up the products of decomposition and thus maintaining 
 the powder in a state of neutrality and preventing auto- 
 catalysis. For this purpose magnesium carbonate or chalk 
 is sometimes used, especially for stabilizing nitrocellulose, 
 the latter usually being applied by using hard water 
 during the boiling process (p. 50). Of organic compounds, 
 camphor was used at one time, but it is objectionable, as it 
 is volatile, and hence powders made with camphor are liable 
 
SMOKELESS PROPELLANTS 71 
 
 to give irregular ballistics after keeping. It is now almost 
 wholly replaced by diphenylamine or mineral jelly (crude 
 vaseline) although other substances have been proposed, 
 such as diphenylurea, urea, etc. 
 
 Both nitroglycerine and nitrocellulose powders consist of 
 colloidal masses of gelatinized nitrocellulose which have been 
 pressed into ribbons, cords, tubes or sheet, these being fre- 
 quently subsequently cut into flakes when intended for use 
 with small arms. A very lively controversy has arisen as to 
 the relative merits of the two classes of powders, and the 
 question cannot be said to be settled. Against nitroglycerine 
 propellants it has been urged that the fumes of unburnt 
 nitroglycerine cause severe headache, especially in the case 
 of heavy ordnance, that they are liable to freeze at low tem- 
 peratures and that the high temperature of explosion causes 
 excessive erosion of the gun barrel. In connection with this 
 latter point Vicille carried out quantitative experiments by 
 firing charges in a closed cylinder from which the only escape 
 for the gases was through a hole i mm. in diameter in a 
 movable plug. The plug was weighed before and after 
 each shot, and the loss in weight taken as a measure of the 
 erosion. He found that Cordite had a much greater erosive 
 effect than Poudre B (a nitrocellulose propellant), and 
 experiments carried out by Sir Alfred Nobel with special 
 Cordites containing from 10 to 60 per cent, of nitro- 
 glycerine showed that within these limits the erosion in- 
 creased by some 600 per cent. On the other hand, it has 
 been stated that the erosion caused by Cordite M.D., which 
 contains much less nitroglycerine than Cordite Mark I., is 
 only slightly, if any, greater than that caused by the average 
 nitrocellulose powder. 
 
 In favour of nitroglycerine powders, it has been urged 
 that they are cheaper to make, give more regular ballistics, 
 and are less liable to produce back-flash than nitrocellulose 
 powders. They keep very well, are not liable to become 
 porous, and the solvent can be almost completely expelled, 
 whereas nitrocellulose powders are liable to become degela- 
 tinized and porous, and it is almost impossible to expel the 
 
72 EXPLOSIVES 
 
 solvent by drying for any reasonable time, and hence it is 
 usually necessary to leave from 2-4 per cent, in the explosive. 
 This gradually evaporates on keeping, and its loss naturally 
 alters the ballistics. Nitroglycerine propellants are also 
 more powerful and dense than nitrocellulose powders, so 
 that somewhat less transport and storage space are required 
 for them, great advantages from a military point of view. 
 
 It is notable that Great Britain and Italy are the only 
 two first-class Powers that rely on nitroglycerine powders 
 for all classes of arms both military and naval. The other 
 Powers either use nitrocellulose powders exclusively, e.g. 
 France, Russia, and the United States, or use nitrocellulose 
 propellants for some arms and nitroglycerine propellants for 
 others, e.g. Germany. As the best test of a propellant is 
 its prolonged trial under use, the war should furnish interesting 
 data as to the relative merits of the two classes of powders. 
 
 NITROGLYCERINE 
 
 The first propellant of this class was discovered by Nobel 
 in 1887 and named Ballistite. It was manufactured 
 originally by incorporating collodion cotton with nitro- 
 glycerine in the presence of benzole, but the method was 
 soon changed, as it was found that incorporation could be 
 carried out by agitating nitroglycerine with collodion 
 cotton in the presence of hot water, agitation being effected 
 by means of compressed air. The dough thus formed is 
 then rolled between rollers heated at 5o-6o C. until a 
 completely homogeneous and colloidal sheet is obtained, 
 which is finally cut into flakes and usually coated with 
 graphite. The Ballistite thus obtained contains on the 
 average equal weights of nitroglycerine and nitrocellulose, 
 and usually a few tenths of a per cent, of diphenylamine 
 to act as a stabilizer. Owing to the high temperature of 
 explosion Ballistite causes severe erosion, and has now been 
 largely displaced by Cordite and similar explosives containing 
 less nitroglycerine. 
 
 Cordite. Cordite was introduced as the British Service 
 
SMOKELESS PROPELLANTS 73 
 
 propellant in 1889, and originally consisted of nitroglycerine, 
 guncotton, and mineral jelly (crude vaseline) in the following 
 proportions : 
 
 Nitroglycerine . . . . . . 58 
 
 Guncotton . . . . . . . . 37 
 
 Mineral jelly . . . . . . . . 5 
 
 In spite of the cooling action of the mineral jelly, however, 
 the erosion caused to the guns was so severe that the com- 
 position had to be modified. The Cordite in use at present 
 has the composition 
 
 Nitroglycerine . . . . . . . . 30 
 
 Guncotton 65 
 
 Mineral jelly . . . . . . . . 5 
 
 and is known as Cordite M.D. to distinguish it from the 
 original Cordite (Cordite Mark I.), which is still used for 
 some purposes. 
 
 The guncotton used in the manufacture of Cordite is 
 usually manufactured from cotton waste by the displace- 
 ment process and contains 13 per cent, of nitrogen, and 85 
 per cent, is insoluble in alcohol-ether. The mineral jelly 
 must not flash below 400 Fahr. (204*5 C.) and must not 
 melt completely below 30 C. It must be free from acidity 
 and mineral impurities and its specific gravity at 38 C. 
 should not be less than -87. 
 
 The manufacture of Cordite is carried out in this country 
 as follows, other nitroglycerine propellants being made by 
 very similar methods. The guncotton, after drying and 
 subsequent cooling, is weighed out in the stoves into india- 
 rubber bags holding about 25 Ibs. each, lead weights covered 
 with leather or rubber being used. These bags are then 
 carried to the nitroglycerine department, and the required 
 weight of nitroglycerine measured off and poured into each 
 bag. The nitroglycerine can be measured out either in 
 fixed lead measuring vessels or in movable gutta-percha 
 jugs. The bags are then taken to the hand-mixing house, 
 where the contents are emptied out and mixed by hand, 
 being finally rubbed gently through a J-in. mesh sieve into 
 other bags. These "hand mixings" are much safer than 
 
74 EXPLOSIVES 
 
 nitroglycerine or guncotton alone, and most factories keep 
 a small stock of cordite paste in this form so as to facilitate 
 regular work. The next process consists in incorporating 
 the paste with a mutual solvent so as to gelatinize the nitro- 
 cellulose. Acetone has been found most suitable for this 
 purpose and is always used, although at an emergency ether- 
 alcohol could be substituted, and this has been done to a 
 considerable extent during the war. The incorporation is 
 carried out in kneading machines of the Werner-Pfleiderer 
 type (Fig. 15) and takes seven hours. The average charge 
 per machine is 150-250 Ibs., and before adding the paste 
 the interior of the machine is moistened with acetone. The 
 paste and the rest of the acetone is then added and the 
 machine set in motion, the mineral jelly being added when 
 the incorporation is half finished, viz. at the end of 3! hours. 
 The stiff dough heats up somewhat during mixing, but the 
 temperature is not allowed to exceed 40 C. and is controlled 
 by the water jacket with which the mixer is provided. 
 To prevent undue loss of acetone a light wooden cover is 
 placed over the machine. The belts of the machines are 
 liable to become strongly electrified, and ensuing sparks 
 may cause an acetone vapour explosion. To remedy this 
 the machines are earthed and the belts dressed with a mixture 
 of glycerine and water. 
 
 When incorporation is complete the charge is placed in 
 bags and removed to the press house, where it is filled into 
 gun- metal cylinders, usually being packed tight by a 
 hydraulic ram, and then pressed through a die in a hydraulic 
 press into cords (hence the name " Cordite ") of various 
 sizes or into tubes, a loo-mesh gun-metal gauze being placed 
 above the die to filter out foreign matter. Pressing into 
 tubes is effected by means of a die with a pin in the centre, 
 but when small sizes are being pressed considerable trouble 
 is experienced through a partial vacuum being formed and 
 consequent collapse of the tube. This can be avoided by 
 using a hollow pin with communication to the outer air 
 (B.P. 27,700!). 
 
 The diameter of the cord depends on the size of the 
 
& 
 
 H 
 
76 EXPLOSIVES 
 
 gun for which the Cordite is wanted. The largest size 
 pressed is approximately -5 of an inch in diameter, but all 
 Cordite is pressed through a die two or three hundredths of 
 an inch larger than the desired diameter of the finished 
 article so as to allow for shrinkage during drying. The 
 smaller sizes of Cordite are reeled on to drums as the cords 
 issue from the press, but the larger sizes are laid out on a 
 table and then cut to the required length. Drying is effected 
 in stoves heated to 40 C. and takes from a few days to 
 two or three months, the time depending on the diameter 
 of the cords, but Cordite Mark I. dries considerably 
 quicker than Cordite M.D. 
 
 After drying is complete, different batches of Cordite 
 are blended in order to assure a product with regular ballistic 
 properties. With the smaller sizes which are on reels, such 
 as rifle Cordite, this is very simply done by re-winding 
 several reels simultaneously on to a single drum. The 
 worker carrying out this process should be carefully earthed, 
 as the dry Cordite passing through his hands becomes 
 strongly electrified. The bigger sizes are blended by laying 
 the boxes containing the different batches in a row and then 
 repacking by transferring a handful from each into a different 
 box. The weight per linear inch is usually relied on as a 
 guide for making up blends. Before blending the sticks 
 are carefully picked over by hand, and any which are badly 
 distorted or contain specks of foreign matter thrown out. 
 These specks are chiefly due to brass dust formed by sliding 
 the cylinders over brass guides in the press house, and are 
 difficult to avoid. Such sticks as are rejected in the packing 
 house are re-worked after being incorporated again with 
 acetone. 
 
 The various sizes of Cordite used by the British Government 
 are denoted by a fraction, the numerator of which denotes 
 the diameter in hundredths of an inch and the denominator 
 the length of the sticks in inches. For example, size f f 
 means that the sticks are '45 in. in diameter and 25 in. long. 
 
 Cordite forms a horny mass of brownish-yellow colour. 
 The smaller sizes are flexible, but the larger sizes break 
 
SMOKELESS PROPELLANTS 77 
 
 easily if bent. Cordite Mark I. is much more flexible than 
 Cordite M.D. It is very insensitive to shock, and when 
 not strongly confined burns fiercely, but does not explode. 
 The cost of manufacturing Cordite during the period January 
 June, 1918, was about 225 per short (?) ton (C.T.J., 1919, 
 p. 189). 
 
 In the manufacture of Cordite 56 Ibs. of acetone are 
 required for every 100 Ibs. of guncotton, and for the sake of 
 economy it is necessary to recover this as far as possible, 
 by suitably treating the air exhausted from the drying 
 stoves. According to one process the acetone-laden air 
 is forced through water contained in a series of closed 
 jars arranged in the form of a cascade, the water and air 
 flowing in contrary directions. By this means the air 
 is robbed of its acetone, and this latter can be recovered 
 by distilling the water with a suitable column. The 
 process in most general use, however, takes advantage 
 of the fact that acetone forms an addition compound with 
 
 QTT 
 
 sodium bisulphite, the formula of which is (CH 3 ) 2 C<qQ -j^. . 
 
 The recovery by this process is carried out by passing the 
 air from the stoves up lead-lined towers which are packed 
 with frames on which strands of wool are woven in a criss- 
 cross pattern (B.P. 25,994 01 ). Simultaneously a strong 
 solution of sodium bisulphite is allowed to trickle down the 
 towers, the towers being usually connected in series, and 
 the liquor from the bottom of one pumped to the top of the 
 next. By this means the liquor and air are brought into 
 contact with one another on the counter-current system 
 and very complete scrubbing is effected. After circulating 
 through the towers the liquor is distilled, a little sodium 
 carbonate being first added, and the acetone thus recovered 
 purified by fractionation. 
 
 In all recovery processes there are two dangers to be 
 guarded against. One is that fire from one stove may be 
 transmitted to other stoves through the pipe line connecting 
 them with the recovery plant. This can be guarded against 
 by inserting fine wire gauzes in the pipes, these acting on 
 
7 8 
 
 EXPLOSIVES 
 
 the same principle as the Davy safety lamp. It is also 
 advisable to make some sections of the pipe of very flimsy 
 construction, so that they would be broken by an explosion 
 wave. The second danger is that Cordite gives off consider- 
 able quantities of nitroglycerine during drying, especially 
 during the later stages, and this is apt to condense and 
 accumulate in the pipes. To avoid this, all pipe lines must 
 be constructed with a fall to one or more points at each of 
 which a catch box is placed from which any accumulation 
 of nitroglycerine can be drawn off safely and conveniently. 
 Some firms make a point of keeping a little paraffin oil of 
 medium consistency (such as medium machinery oil) in 
 these catch boxes, as this has a great effect in moderating 
 the explosive properties of nitroglycerine. 
 
 The amount of solvent given off during the later stages 
 of drying large size Cordite, especially Cordite M.D., is so 
 small that it does not pay to recover it. Hence it is usual 
 to transfer these larger sizes to non-recovery stoves after 
 they have lost the greater part of their solvent. 
 
 The following gives the name, composition, and physical 
 form of the nitroglycerine propellants used for military 
 purposes by European Powers. The other Powers use 
 nitrocellulose propellants : 
 
 Country. 
 
 Propellant. 
 
 N.G. 
 
 N.C. 
 
 MJ. 
 
 Form. 
 
 Remarks. 
 
 Gt. Britain 
 
 Cordite Mark I. 
 M.D. II. 
 
 58 
 30 
 
 37 
 65 
 
 5 
 5 
 
 {Sticks } 
 (Tubes ) 
 
 N.C. has 13 % N. 
 
 Italy 
 
 Filite 
 
 50 
 
 50 
 
 
 
 Cords 
 
 i % Ph 2 NH. 
 
 
 Solenite 
 
 
 64 
 
 3 
 
 
 N.C. 12-5 %N. 
 
 Germany 
 
 Wiirfelpulver 
 Rohrenpulver 
 
 33 
 
 50 
 
 64 
 
 3 
 
 Cubes 
 Tubes 
 
 Contains Ph 2 NH. 
 
 Cordite is very largely used for sporting rifles, and in 
 addition one or two nitroglycerine propellants are manu- 
 factured in this country for sporting purposes. Of these 
 Axite and Moddite are the best known. The former is 
 practically Cordite M.D. to which 2, per cent, of potassium 
 nitrate has been added. The latter contains rather more 
 
SMOKELESS PROPELLANTS 79 
 
 nitroglycerine, and Marshall (" Explosives ") gives the result 
 of an analysis as follows : 
 
 Nitroglycerine . . . . . . 38*7 
 
 Nitrocellulose 56-8 
 
 Mineral jelly . . . . . . 4-3 
 
 Volatile . . . . . . . . -2 
 
 NITROCELLULOSE PROPELLANTS 
 
 These all consist of collodion cotton gelatinized and 
 rendered colloidal by the use of solvents and then pressed 
 into cords, tubes, or ribbons in much the same way as Cordite. 
 Gelatinization can be carried out with acetone, but the 
 colloid thus obtained is very brittle and becomes more so 
 on keeping, so that ether- alcohol is nearly always used. As 
 this does not gelatinize nitrocellulose of high nitrogen 
 content, it is very desirable to use a collodion cotton which 
 is almost completely soluble in ether-alcohol, as otherwise 
 ungelatinized fibres will render the resulting colloid porous. 
 Porosity is usually accompanied by instability as oxidation 
 takes place, and by irregular ballistics and excessive pressures 
 due to combustion spreading through the body of the 
 powder and not remaining confined to the surface. 
 
 Nitrocellulose propellants for rifled arms usually contain 
 nothing but nitrocellulose, together with a small amount of 
 stabilizers and a slight percentage of solvent which cannot 
 be removed in any reasonable time in the drying stoves. 
 More rarely they contain a little potassium nitrate, but 
 propellants containing nitrates are more used for shot guns 
 than for rifled arms, and as they are manufactured by 
 somewhat different methods they will be treated separately. 
 As gelatinization is almost invariably brought about by 
 alcohol-ether, the somewhat dangerous process of drying 
 the nitrocellulose can be avoided, the water being displaced 
 by alcohol as described on page 52. 
 
 Almost all countries have adopted nitrocellulose pro- 
 pellants for military purposes, and the manufacture of the 
 United States Military Powder serves as a general descrip- 
 tion of the methods employed. 
 
8o EXPLOSIVES 
 
 U.S. Military Powder. The nitrocellulose is prepared 
 from cotton waste either by the displacement process or 
 in nitration centrifuges, and contains 127 per cent, of nitrogen. 
 It is almost completely soluble in alcohol-ether, and is 
 pulped, washed, and whizzed in the ordinary way. Forty 
 pounds of the wet pulp, which contains 30 per cent, of 
 water, are then packed into a cylinder and treated with 
 alcohol. At first no pressure is applied and the runnings 
 are almost pure water, but after rather more than half a 
 gallon of water has run out pressure at 200 Ibs. per square 
 inch, and finally at 3500 Ibs. per square inch, is applied. The 
 block or " cheese " thus obtained weighs some 38 Ibs. 
 and contains 
 
 Nitrocellulose . . . . 73 per cent. 
 
 Alcohol . . . . . . . . 23 
 
 Water 4 
 
 The blocks are roughly broken up by wooden mallets and 
 the disintegration completed by running them in a Werner 
 and Pfleiderer mixing machine (Fig. 15, p. 75) for a quarter 
 of an hour. Bach machine takes a charge of three blocks, 
 corresponding to 42 Ibs. of pure nitrocellulose. After 
 disintegration is complete 48$ Ibs. of ether, in which 6 oz. 
 of diphenylamine has been dissolved, are added to each 
 machine and incorporation carried on for 45 minutes. The 
 charge is then transferred to hydraulic presses and sub- 
 mitted to a presstire of 3500 Ibs. per square inch, whereby 
 it is converted into elastic horny blocks weighing about 
 40 Ibs. each, but no solvent is squeezed out during the com- 
 pression. To get rid of foreign matter, such as wood chips 
 and hard nodules, the colloid is next filtered through a 
 3O-mesh gauze resting on a heavy steel plate perforated 
 with ^-in. holes. Filtration is brought about by applying 
 a pressure of 3500 Ibs. per square inch, and the powder issues 
 in the form of cords. These are again pressed into a block 
 at 3500 Ibs. per square inch and this block then squirted 
 into multitubular cords in a hydraulic press, the cords 
 having different diameters and a different number of perfora- 
 tions (from i to 7), according to the purpose for which the 
 
SMOKELESS PROPELLANTS 81 
 
 powder is required. These multitubular cords are immedi- 
 ately cut up into short lengths by means of revolving knives 
 and dried in stoves. 
 
 During the squirting of the cords a great deal of heat is 
 evolved, so that water-cooled dies must be used. It is not 
 advisable, however, to carry this cooling too far, as the 
 cutting knives work best at 30 C. 
 
 After squirting and cutting the powder contains about 
 48 per cent, of solvent, rather more than half of which is 
 ether. Owing to its volatility and to the fact that it does 
 not form addition compounds easily, ether is much more 
 difficult to recover than acetone, and not more than 40 per 
 cent, can be recovered economically, and this only by 
 using condensers served with chilled brine. The tempera- 
 ture of the condensers, however, must not be reduced too 
 far, or the water vapour which comes over simultaneously 
 may be frozen and so cause a stoppage. The ether recovered 
 is mixed with a good deal of alcohol, and is best returned 
 to the ether factory. The finished powder contains from 
 3 to 7 per cent, of solvent, depending on the size. 
 
 Poudre B. This is the French military powder, and is 
 made from a mixture of soluble and insoluble nitrocellulose 
 gelatinized with ether-alcohol to which some diphenylamine 
 and amyl alcohol have been added. The latter is used as 
 it is left in the finished explosive, and is less volatile than 
 alcohol or ether. After incorporation the mass is worked 
 between rollers at 70 C., and the rolled sheets either cut up 
 in strips or flakes or squirted through a die into ribands. 
 It is then dried at 50 C., and finally frequently washed with 
 water to reduce the amount of solvent. 
 
 The powder is decidedly porous, and several disastrous 
 explosions have been attributed to its spontaneous com- 
 bustion, the most notable of which were the total destruc- 
 tion of two battleships, the lena in 1907 and the Libert e in 
 1911. 
 
82 EXPLOSIVES 
 
 SHOT-GUN SMOKELESS PROPEU,ANTS 
 
 Much quicker burning powders are necessary for use with 
 shot guns than with rifled arms, and in order to produce a 
 good pattern, i.e. in order that the shot may not spread 
 unduly, comparatively little pressure must be present at 
 the moment that the charge leaves the muzzle. 
 
 Almost all shot-gun smokeless propellants are nitro- 
 cellulose powders to which as a rule a certain amount of 
 barium or potassium nitrate has been added, and they may 
 be roughly divided into two classes, viz. condensed powders 
 and bulk powders. The former are completely gelatinized 
 powders and are made by methods very similar to those 
 used for rifle propellants, the necessary increased rate of 
 combustion being attained by forming them into thin flakes 
 or small grains. Munroe describes the manufacture as 
 being carried out in the United States as follows : 
 
 Finely pulped wet nitrocellulose is mechanically agitated 
 with water containing 5 per cent, of barium nitrate and 2 
 per cent, of potassium nitrate in a vertical jacketed pan. 
 An emulsion of amyl acetate and water containing barium 
 and potassium nitrate is then added, and granulation allowed 
 to take place at the ordinary temperature for a few minutes, 
 after which steam is turned into the jacket and agitation 
 and heating continued for 5-6 hours, during which time 
 most of the amyl acetate and some water distil off and are 
 condensed. The contents of the vessel are then run out 
 and the grains dried and sieved, oversized and undersized 
 grains being added to the next charge in the proportion 
 of 250 Ibs. of waste to 450 Ibs. of fresh nitrocellulose. 
 
 Another American sporting powder, Indurite, is made 
 from guncotton, the soluble portion being first extracted 
 with methyl alcohol and the residue then gelatinized with 
 nitrobenzole, this latter being finally removed by treatment 
 with hot water. 
 
 One of the great disadvantages of condensed powders 
 lies in the fact that owing to their small bulk they require 
 special cartridge cases. Also in loading cartridges the 
 
SMOKELESS PROPELLANTS 83 
 
 powder is always measured out, and consequently the higher 
 the density of the powder the greater is the error in weight 
 due to slight differences in volume. For this reason " bulk " 
 powders are usually preferred to the condensed powders. 
 These are composed of grains of nitrocellulose, with or 
 without the addition of small quantities of other substances, 
 the grains being gelatinized on the surface. Such bulk 
 powders are known as 42 -grain and 33 -grain powders, 
 meaning that the charge for a 12-bore gun is 42 and 33 
 grains respectively, and that the volume occupied by this 
 amount is the same as that of the standard black powder 
 charge, viz. 3 drams. Thirty-grain powders are also made, 
 but in these gelatinization is almost complete, so that they 
 are more in the nature of condensed powders. 
 
 Most shot-gun powders contain barium and/or potassium 
 nitrate, and in many cases it is found best to incorporate a 
 much greater quantity than is desired in the finished powder, 
 the excess being subsequently removed by dissolving out 
 with water. This yields a more bulky powder, and facilitates 
 the production of one having a correct weight for a given 
 volume. 
 
 The nitrocellulose used for shot-gun powders usually con- 
 tains from 12 '0 to 12 '8 per cent, of nitrogen, but the nitrogen 
 content of nitrolignite powders is frequently lower than this. 
 
 The first process in manufacturing bulk powders is 
 graining the nitrocellulose. This can be done in several 
 ways, such as grinding in edge runners while wet or in ball 
 mills, the balls being made of lignum vitse. During this 
 process the other ingredients, such as nitrates, are added 
 and the incorporating continued until mixing is complete 
 and the grains are judged to be suitable for the class of 
 powder desired. They are then roughly sifted and dried 
 in stoves at a low temperature. After drying they are 
 again sifted to remove dust and then gelatinized on the 
 surface. This is effected in revolving drums provided with 
 ridges so as to keep the powder in motion. The solvent 
 is generally sprayed in, as if added in bulk it does not become 
 evenly distributed, with the result that some of the grains 
 
84 EXPLOSIVES 
 
 remain ungelatinized, while others become overgelatinized 
 and may adhere together and form lumps. After spraying 
 and thorough mixing so as to ensure even distribution of 
 the solvent, the grains are allowed to steep for a few hours 
 and then dried. The drying is best carried out in two 
 stages, as during the later stages the amount of solvent 
 given off is so small that it is not worth recovering. In 
 order to recover as much solvent as possible, the first part 
 of the drying is carried out in revolving drums in vacuo, 
 the vacuum pump being connected with the hollow spindle 
 of the drum through a copper coil condenser cooled with 
 chilled brine. A fine gauze is interposed between the drum 
 and the condenser in order to prevent dust being carried 
 over mechanically. In order to guard against pressure 
 being set up in the drum through the condenser becoming 
 frozen or the dust filter choked, the cover of the charging 
 hole is held in position by the vacuum only, so that should 
 the vacuum fail it falls off and at once releases any pressure. 
 After as much as possible of the solvent has been recovered, 
 the powder is removed to stoves and the drying completed 
 by spreading it in thin layers on shallow trays, no attempt 
 being made to recover solvent, as it is given off too slowly. 
 When drying is complete the powder is again sifted to 
 remove oversized and undersized grains and then allowed 
 to age for about six weeks. The ageing period is necessary 
 in order that the powder may take up a certain amount of 
 moisture from the atmosphere, and reach the state in which 
 it will be used. The ballistic properties of each batch are 
 then tested, and the various batches carefully blended so as 
 to produce a powder with standard properties. This blending 
 is most essential if different lots of the same powder are to 
 produce the same effect in use. The production of 30-grain 
 powders involves the use of nitrocellulose with a high nitro- 
 gen content in order that the smaller weight of powder may 
 produce the same power, and to reduce the rate of burning 
 gelatinization must be complete. At the same time the 
 bulk of the powder must be maintained in order that a 
 30-grain charge may occupy the standard volume of 3 drams. 
 
SMOKELESS PROPELLANTS 85 
 
 This is effected by incorporating the nitrocellulose with 
 several times its weight of barium or potassium nitrate, 
 and then drying and gelatinizing freely. The dough is 
 then pressed in much the same way as a condensed powder, 
 and after drying the nitrate is almost completely removed 
 by treatment with warm water. The same method is used 
 in making 33-grain powders, although the gelatinization is 
 not so complete. 
 
 As regards the solvents used in preparing bulk powders, 
 acetone alone is not very suitable, as it produces a brittle 
 colloid. It is, however, used sometimes in conjunction 
 with alcohol. Alcohol-ether mixture gives excellent results, 
 but is very difficult to recover. Ethyl acetate and amyl 
 acetate are both used to a large extent either alone or in 
 conjunction with other solvents, and the use of benzole has 
 also been proposed. Sometimes an aromatic nitrohydro- 
 carbon, such as dinitrobenzole or dinitrotoluol or trinitrotoluol, 
 is added to the solvent in order to assist the gelatinization. 
 Such compounds naturally remain in the powder, and con- 
 sequently when used sufficient nitrate for their combustion 
 must be added. A certain amount of an organic dyestuff , 
 such as aurine, is also generally added to the solvent in 
 order to improve the appearance of the powder. In some 
 cases also a solution of collodion is added, so as to varnish 
 the outsides of the grains. This makes them somewhat 
 less liable to take up moisture, and at the same time slows 
 down the rate of combustion. This latter is also effected by 
 glazing the finished powder by rumbling with a little graphite. 
 The table on page 86 shows the composition of a few well- 
 known sporting powders manufactured in this country. 
 
 Of the 33-grain powders, Smokeless Diamond is probably 
 the most used in this country. It chiefly consists of nitro- 
 cellulose and barium nitrate, the grain being glazed with 
 graphite. 
 
 Schultze Powder, which was one of the earliest smokeless 
 shot-gun propellants, is a nitro-lignine powder and is made 
 from wood. The wood is first carefully purified to free it 
 as far as possible from pectose and non-cellulosic substances. 
 
86 
 
 EXPLOSIVES 
 
 and then nitrated. After washing the nitro-lignine is 
 impregnated with barium nitrate, and the grains then gela- 
 tinized on the surface and hardened by spraying with ethyl- 
 alcohol or other suitable solvent. Schultze Powder has 
 always been a favourite with sportsmen for use with the 
 shot gun, but up to the present nitro-lignine has not been 
 found suitable for use with rifled arms. Probably the 
 German Government has evolved some method of rendering 
 it suitable, as the Allied blockade cut off the supply of cotton. 
 
 
 
 
 Imperial 
 Schultze. 
 
 Amberite. 
 
 E.C. 
 
 Schultze. 
 
 Kyroch's Sporting 
 Smokeless. Ballistite. 
 
 N.G. .. 
 
 
 
 
 _ 
 
 _ 
 
 _ 
 
 37-6 
 
 N.C. .. 
 
 
 
 . - 
 
 7 1 
 
 79 
 
 62-1 
 
 52-1 62-3 
 
 Nitro-lignin 
 
 
 
 80-1 
 
 
 
 
 
 
 D.N.T. 
 
 
 
 
 
 
 
 
 
 
 
 I9'5 
 
 KN0 3 
 
 
 
 
 
 I "2 
 
 4'5 
 
 1-8 
 
 
 Ba(N0 3 ) 2 
 
 
 
 10-2 
 
 18-6 
 
 7'5 
 
 26-1 
 
 22*2 
 
 Camphor 
 
 
 
 
 
 . 
 
 
 
 
 i 
 
 W.M. 
 
 
 
 
 
 **4 
 
 3-8 
 
 
 
 2*7 
 
 M.J. .. 
 
 
 
 7*9 
 
 5'8 
 
 
 
 4'9 
 
 
 
 Starch 
 
 
 
 
 
 
 
 
 3'5 
 
 
 
 Carbon 
 
 
 
 
 
 
 
 
 
 
 
 Ash .. 
 
 
 
 . 
 
 
 
 . 
 
 
 
 '9 
 
 Volatile 
 
 
 
 1-8 
 
 2 
 
 l-l 
 
 1-6 
 
 I '2 
 
 Schultze cube Powder is a 30-grain fully gelatinized 
 powder, and is probably derived from cotton or wood pulp. 
 In France, where the manufacture of explosives is a State 
 monopoly, the following sporting powders are provided : 
 
 
 Poudre S. 
 
 Poudre J. 
 
 Poudre M. 
 
 Poudre T. 
 
 N.C 
 
 
 
 65 
 
 83 
 
 71 
 
 TOO 
 
 Ba(N0 3 ) 2 
 
 
 
 29 
 
 
 20 
 
 
 
 KN0 3 .. 
 
 
 
 6 
 
 
 
 5 
 
 Am 2 Cr 2 O 7 
 
 
 
 
 
 M 
 
 
 
 
 K 2 Cr 2 7 
 
 
 
 
 
 3 
 
 
 
 Camphor 
 
 
 1 
 
 
 3 
 
 
 
 Gelose .. 
 
 
 
 
 
 
 
 i 
 
 
 
 Number of grains per gram 
 Charge for 1 6-calibre gun wit 
 
 h 
 
 1000 
 
 250-300 
 
 3500 2500 
 
 30 grams No. 6 shot 
 
 
 2-4 2-8 
 
 2'I I'Q 
 
 Density 
 
 
 500 -750 
 
 '475 
 
 565 
 
 Mean pressure, Kg. per cm. 2 
 
 445 
 
 35 
 
 5OO 
 
 47 
 
SMOKELESS PROPELLANTS 87 
 
 Poudre T bis is very similar to Poudre T, but is rather 
 quicker. 
 
 Poudre S is made by mixing the ingredients wet under 
 light edge runners and then drying and incorporating with 
 ethyl-alcohol, the dough being formed into grains by passing 
 it through a sieve. It produces a great deal of fouling. 
 
 Poudre J is made by incorporating the nitrocellulose with 
 ether-alcohol and very finely ground bichromates and then 
 rolling out. 
 
 Poudre M is made in much the same way as Poudre S, 
 but the grains receive a final treatment with ether-alcohol 
 in which camphor and collodion are dissolved. It is a powder 
 which is apt to develop excessive pressures. 
 
 Poudre T contains no nitrate or bichromate, and the 
 gelatinization is brought about by a mixture of ethyl acetate 
 and acetone. 
 
 Of the Belgian sporting powders, Mullerite, which contains 
 no mineral salts, and Clermonite, which is a mixture of nitro- 
 cellulose and barium and potassium nitrate, are the best knowni 
 
 Several German powders have acquired a good reputa- 
 tion. Among them may be mentioned Fasan and Tiger, 
 which are roughly 42-grain powders ; Rothweil and Walsrode, 
 33-grain powders ; and Saxonia and Adler-Marke, 30-grain 
 powders. They are made in much the same way as the 
 corresponding British powders. Walsrode is gelatinized with 
 ethyl acetate. 
 
 AUPHATIC SOLVENTS 
 
 The solvents used in the manufacture of smokeless pro- 
 pellants are expensive and add considerably to the cost of 
 manufacture. Alcohol up to the present has been obtained 
 by the fermentation of sugars or starches, molasses, potato 
 and maize being the chief raw materials. Recently, how- 
 ever, sawdust and the sulphite liquor obtained as a waste 
 product in the manufacture of paper pulp has been used, as 
 on hydrolysis with acids the cellulosic substances are broken 
 down into fermentable sugars. Considerable difficulties have 
 been met with in carrying out the process on a commercial 
 
88 EXPLOSIVES 
 
 scale, but these are gradually being overcome, and a good 
 deal of attention is being paid to the subject in the United 
 States. A purely synthetic process is also in course of 
 development, and consists in converting acetylene into 
 acetaldehyde and then reducing this to alcohol. 
 
 Ether has usually been manufactured by the action of 
 sulphuric acid on alcohol, but probably the catalytic de- 
 hydration of alcohol will prove to be a less costly process in 
 the future. 
 
 Acetic acid, used for the manufacture of ethyl acetate 
 and acetone, is usually obtained as a by-product in the 
 carbonization of wood. Unfortunately coniferous woods are 
 quite unsuited for the purpose, and even with hard woods 
 the yield is very poor. Here again attempts are being made 
 with considerable success to introduce purely synthetic 
 methods. In these the starting out substance is acetylene, 
 which, when treated with sulphuric acid in the presence of 
 mercuric sulphate, takes up water and passes into acetalde- 
 hyde, this being readily oxidized to acetic acid 
 
 CH CH 3 CH 3 
 
 III ->l->| 
 
 CH CHO COOH 
 
 The process is an old one, but it is only during the last two 
 or three years that any success has been achieved, and it is 
 still too early to predict to what extent the process is likely 
 to come into general use. One of the great troubles is the 
 tendency of the aldehyde to polymerize the resinous sub- 
 stances. 
 
 Acetone has generally been manufactured by the dry 
 distillation of calcium acetate, this decomposing at 300 C. 
 into the carbonate and acetone 
 
 (CH 3 CO) 2 Ca =CaC0 3 + (CH 3 ) 2 CO 
 
 Acetone, accompanied by fusel oil, can, however, also be 
 obtained by the fermentation of starch, and seaweed and 
 horse-chestnuts also appear suitable for the purpose. In 
 Great Britain a company was floated in 1912 to work the 
 process, the primary object, however, being to obtain the 
 
SMOKELESS PROPELLANTS 89 
 
 fusel oil and from it synthetic rubber. This latter part of 
 the scheme does not seem to have been a success, but the 
 company has produced acetone for war purposes. In the 
 United States a large plant for the fermentation of seaweed 
 has been put down by the Herculose Powder Company on 
 the Pacific sea-board, potash being obtained amongst other 
 things as a by-product, and in Great Britain experimental 
 work has been done at Penzance in Cornwall. In these 
 processes the residues, after the extraction of the valuable 
 products, are burnt in gas producers and so furnish a large 
 percentage of the heat required for running the works. 
 Iodine and bromine are also recovered, but for this purpose 
 the weed should be cut from the sea bottom at a considerable 
 depth, as that washed up on to the shore is comparatively 
 poor in these elements. 
 
 LITERATURE 
 
 The manufacture of Cordite is described in detail in "Treatise on 
 Service Explosives," 1907, published by Authority, and an illustrated 
 description of the New Explosives Company's Cordite plant appeared in 
 Arms and Explosives, 1898, p. 242. 
 
 Litigation on the Cordite patents is referred to in A.E., 1897, pp. 89, 
 106, 116, 172. 
 
 The manufacture of the United States Military Smokeless Powder is 
 given in detail by E. C. Worden in "Nitrocellulose Industry," vol. ii., 
 1911 ; and also in the Journal of the United States Artillery, 1910, p. 140. 
 
 The use of nitromethane for assisting gelatinization is covered by 
 F.P. 394,992. The addition of nitroguanidine for reducing the tempera- 
 ture of explosion is covered by U.S.P. 899,855, and the use of tartrates 
 for the same purpose by E.P. I5,565 06 . 
 
 Producing flaked powders with knobs or ribs to prevent the flakes 
 lying face to face is the subject of E.P. I2,892 06 , 2I.779 05 . 
 
 Experiments on the stability, or lack of stability, of Poudre B are 
 described in P.5., xv., i; 5.5., 1910, pp. 345, 369, 389; 1911, pp. 303, 
 327, 441, 464. 
 
 Vielle's experiments on erosion are described in P.5., xi. 157. 
 
 Smokeless propellants in general are discussed in 5.5., 1913, pp. 126, 
 2 ^5, 307, 330, 352, and the relative merits of nitroglycerine and nitro- 
 cellulose propellants in 5.5., 1913, pp. 368, 393. 
 
 Experiments on the behaviour of smokeless propellants when burnt 
 in quantities of from i to 10 tons are described with photographs in 5.5., 
 1914, PP. 187, 217. 
 
 A large number of works on interior and exterior ballistics, most of 
 them more or less mathematical, have been published from time to time, 
 but the following can be recommended : 
 
 J. M. Ingalls, " Interior Ballistics," New York, 1912. 
 
 C. Cranz, "Lehrbuchder Ballistik," 3 vols., Berlin, 1910-1913. 
 
 P. Charbonniere, "Balistique Interieure," Paris, 1908. 
 
 A. C. Crehore and G. O. Squier, " Polarizing Photo-Chronograph," 
 New York, 1897. 
 
SECTION IV.-BLASTING EXPLOSIVES 
 
 FOR blasting hard rock a powerful and brisant explosive 
 is required, more especially in operations such as tunnelling, 
 where it is not required to obtain the material in large 
 pieces, and an explosive with high density is also desirable 
 for this class of work, as the cost of making bore holes in 
 hard material is very considerable. Softer minerals require 
 a slower burning explosive, as otherwise they are shattered 
 too much and excessive amounts of dust are produced. 
 For this reason and on account of its cheapness, gunpowder 
 is still extensively used for quarrying. For work in coal 
 mines a mild explosive is required for coal getting in order 
 that the material shall not be unduly shattered, and a more 
 brisant explosive for ripping and clearing away stone. At 
 the same time the explosive used must not fire the mine 
 gases nor cause a coal-dust explosion. Explosives for use 
 in fiery mines are known in this country as Permitted 
 Explosives, and are treated in the next section. 
 
 For use in wet situations a satisfactory blasting explosive 
 should not be readily spoilt by water, although this trouble 
 can be largely got over by using waterproof wrappers. 
 Finally, as blasting explosives are largely used by ignorant 
 people, they should be as fool-proof as possible. Explosives 
 containing nitroglycerine are liable to freeze, and in this 
 state are difficult to detonate. There is a statutory obliga- 
 tion to thaw out such explosives before use in a proper 
 warming pan, but in spite of this accidents occur every 
 year through miners thawing out frozen explosives over a 
 fire. The warming pans are very simple in construction 
 and consist of felt-covered, double-walled tin-plate vessels, 
 the explosive being placed in the inner vessel and warm 
 water in the annular space. By their use explosives can 
 
BLASTING EXPLOSIVES 91 
 
 be thawed in safety, but the process takes time, and to some 
 minds the temptation to thaw over a fire seems irresistible. 
 
 Except in the case of very heavy charges, the danger 
 from fumes is not great when surface blasting is carried on, 
 but in underground workings the case is different. The 
 poisonous fumes that result from the detonation of an 
 explosive include carbon monoxide, due in part to lack of 
 oxygen and in part to the paper wrapper. L,ack of oxygen 
 in the explosive mixture can be remedied by the addition 
 of more oxidizing agent, but it is not safe to remove the 
 wrapper before inserting the cartridge into the bore hole. 
 Metal foil wrappers might be substituted for paper, but this 
 would only be changing one evil for another, as the metallic 
 oxide in itself would be objectionable unless aluminium or 
 tinfoil were used. The only satisfactory safeguard would 
 seem to lie in ample ventilation. Explosives containing 
 barium or lead salts give off poisonous fumes due to the 
 salts of these metals, and ammonium perchlorate explosives 
 are very liable to evolve chlorine unless alkali nitrate is also 
 present in sufficient quantity to provide a base for the 
 chlorine to unite with. Finally, explosives containing nitro- 
 aromatic hydrocarbons may give off poisonous fumes of 
 these if detonation is incomplete through insufficient oxygen 
 or through the use of too weak a detonator. 
 
 All composite blasting explosives consist of an oxidizing 
 agent and oxidizable matter, any or none of which may be 
 explosives in themselves. In gunpowder, for example, the 
 sulphur and charcoal provide the combustible matter and 
 the nitre the oxidizing agent, none of these being capable 
 of explosion alone. Blasting Gelatine, on the other hand, 
 consists of nitrocellulose as combustible matter and nitro- 
 glycerine as an oxidizing agent, both these ingredients 
 being capable of exploding alone. An intermediate stage 
 is represented by Gelignite, in which an explodable and 
 a non-explodable oxidizing agent (nitroglycerine and potas- 
 sium nitrate) is used in conjunction with explodable and 
 non-explodable combustible matter (nitrocellulose and 
 wood meal). 
 
92 EXPLOSIVES 
 
 The following list gives the chief oxidizing agents avail- 
 able industrially, together with the maximum amount of 
 available oxygen per 100 grams : 
 
 N.G. ..3'5 I KC10 3 .. ..37 
 
 KNO 3 . . 40 NaClO 3 . . . . 45 
 
 NaNO 3 .. 47 KC1O 4 .. ..46 
 
 AmNO 3 . . 20 NaClO 4 . . . . 52 
 
 Ba(NO 3 ) 2 . . 30 , AmClO 4 . . 27 
 
 Pb(NO 3 ) 2 . . 24 (PbO) Ba(ClO 4 ) 2 . . 38 
 
 Pb(N0 3 ) 2 . . 29 (Pb) 
 
 Of these it should be noted that nitroglycerine, ammonium 
 nitrate, and ammonium perchlorate are all capable of being 
 exploded, although ammonium nitrate is only exploded 
 with difficulty. The chlorates are also capable of exploding, 
 as they are endothermic compounds and one or two accidents 
 have been due to chlorate explosions. 
 
 A large number of combustible matters is available, of 
 which the following are the most important : 
 
 Nitrocellulose. 
 
 Dinitrobenzole. 
 
 Di- an4 tri-nitrotoluol. 
 
 Mono- di- and tri-nitronaphthalene. 
 
 Wood meal. 
 
 Charcoal. 
 
 To a lesser extent starch, flour, potato meal, and the 
 like are also used, as they help the resulting mixture to bind 
 together. Castor oil enters into the composition of certain 
 chlorate mixtures, as it renders them less sensitive to shock. 
 
 Finally, inert substances such as kiesselguhr, silica, mica, 
 etc., are used for absorbing nitroglycerine in some explosives 
 such as Dynamite, and neutral salts such as sodium chloride 
 are used as "coolers " in Permitted Explosives. 
 
 Blasting explosives, other than black powder, can be 
 roughly divided into four classes, viz. : (i) Dynamite and 
 its Congeners ; (2) Gelatinized Explosives ; (3) Chlorate 
 Mixtures ; (4) Ammonium Nitrate Explosives. The division 
 is not a very sharp one, but is the most convenient method 
 of classification, 
 
BLASTING EXPLOSIVES 93 
 
 DYNAMITE AND ITS CONGENERS 
 
 When Nobel first introduced nitroglycerine as a blasting 
 explosive it was used in the liquid form, but was frequently 
 transported in a frozen condition in order to minimize the 
 danger. In spite of all precautions, however, numerous 
 accidents occurred, so that the transport of nitroglycerine 
 either in the liquid or in the frozen state was soon forbidden. 
 This caused Nobel to seek some inactive substance that 
 would absorb the oil and render its conveyance and use 
 safe without interfering with its explosive properties. He 
 found kiesselguhr, a form of siliceous earth found in Germany, 
 Austria, Norway, Australia, and Scotland, to be most suitable, 
 as good qualities will take up three times their weight of 
 nitroglycerine and still remain dry ; but in his patent he also 
 claimed the use of other materials such as ground brick, 
 dry plaster, etc. He named the explosive thus obtained 
 Dynamite. 
 
 Kiesselguhr, or guhr as it is usually called, varies very 
 much in quality, some samples being quite unsuited for 
 Dynamite manufacture owing to their very poor absorptive 
 power or high content of sand. The content of organic 
 matter is also very variable, running from 4-5 per cent, to 
 as high as 35 or 40 per cent, in the case of many of the 
 Scotch deposits. In any case, the guhr requires to be 
 thoroughly calcined before use in order to burn this off, 
 and must then be sifted through a 3O-mesh sieve in order 
 to get rid of sand. This latter process is absolutely essential, 
 as grains of sand would give rise to undue friction when 
 making up the cartridges and might well cause an explo- 
 sion. After calcining the guhr usually has a pink colour 
 due to oxide of iron, but some samples are almost white, 
 and when this is the case most manufacturers add a little 
 red ochre in order that the finished Dynamite may have 
 the characteristic red-brown colour. 
 
 The manufacture of Dynamite is carried out as follows : 
 The guhr is weighed out after sieving into wooden boxes 
 or rubber bags and taken to the nitroglycerine department, 
 
94 EXPLOSIVES 
 
 where the requisite quantity of nitroglycerine is measured 
 out and added. The boxes or bags are then carried to the 
 mixing house, where they are emptied out into lead tanks 
 and the contents thoroughly mixed. This can be done by 
 hand by rubbing the loose Dynamite repeatedly through a 
 coarse sieve (about 8-mesh), or after a rough mixing by 
 hand the loose Dynamite can be transferred to a Werner 
 and Pfleiderer mixing machine (Fig. 15, p. 75) and mixing 
 then completed mechanically. The resulting powder should 
 not feel moist, but at the same time it must not be too dry 
 or it will not bind properly in the dynamite pumps and will 
 not detonate easily in use. If too moist more guhr can 
 be added or from '5 to i per cent, of barium sulphate can 
 be mixed in, as this lowers the absorptive capacity of the 
 guhr. If too dry more nitroglycerine must be added. 
 With a little experience it is easy to judge whether the 
 explosive is of the right consistency or not. Dynamite 
 mixing is an extremely unpleasant occupation for those 
 not used to it, as the dusty explosive enters the mouth and 
 nose and causes very severe headache. Those engaged 
 continuously in the process as a rule get acclimatized, but 
 when, as is often the case, the explosive is only manufactured 
 intermittently the workers suffer severely, even those who 
 have been used to handling nitroglycerine jellies getting 
 headache at first when put on to Dynamite. 
 
 For converting the loose Dynamite into cartridges the 
 Guttmann dynamite pump (Fig. 16) is almost universally 
 used. It consists of a plunger working vertically between 
 two loose guides, motion being imparted by a horizontal 
 lever. The end of the plunger is shod with lignum vitae 
 and works in a brass tube of the same diameter as the 
 finished cartridge, plenty of clearance being allowed between 
 the plunger and the brass tube so as to avoid friction. 
 The upper end of the brass tube is fixed into a brass block, 
 usually covered with leather, to which is attached the lower 
 end of a conical bag made of cloth or light leather. The 
 upper and wider end of this bag is attached to a boss further 
 up the plunger by means of three strings, so that at each 
 
BLASTING EXPLOSIVES 
 
 95 
 
 upward stroke of the plunger the bag gets a jerk. An 
 inverted bell is fixed to the plunger just above the bag, so 
 as to prevent explosive working up into the guides. 
 
 In pumping cartridges the loose Dynamite is fed into 
 the bag with a wooden scoop, and the plunger then worked 
 up and down by hand. Bach upward stroke jerks some of 
 the powder into the brass tube, which the following down- 
 
 FIG. 1 6. Dynamite Pump. 
 
 ward stroke compresses into a more or less coherent mass 
 which issues at the lower end as a rod. This is broken off 
 from time to time and wrapped in parchment paper. The 
 most usual diameters for Dynamite cartridges are f in. and 
 | in., and the most usual weight 2 oz. Ordinary Dynamite, 
 consisting of 75 per cent, of nitroglycerine and 25 per cent, 
 of guhr, with the possible addition of small quantities of 
 
9 6 
 
 EXPLOSIVES 
 
 ochre for colouring, or a trace of calcium or magnesium 
 carbonate to render it more stable, is known in Europe 
 as Dynamite No. i to distinguish it from the less powerful 
 Dynamites formerly made to some extent, viz. Dynamite 
 No. 2, consisting of 18 per cent, of nitroglycerine, 10 per 
 cent, of carbon, and 72 per cent, of nitre ; and Dynamite 
 No. 3, consisting of 37*5 per cent, of nitroglycerine, 12*5 
 per cent, of guhr, and 25 per cent, each of wood meal and 
 nitre. In the United States, however, guhr Dynamite 
 goes by the name of Giant Powder, the name Dynamite 
 being reserved for mixtures of nitroglycerine, wood meal, 
 and sodium nitrate. 
 
 In France, in addition to guhr Dynamite, Dynamites 
 are also made from a mineral called randanite, composed 
 of weathered felspar, with or without the addition of 
 absorbent silica either from natural sources or manufactured 
 by passing silicon fluoride into water. The Government 
 factory at Vonges, for example, makes the following 
 grades : 
 
 No. x. 
 
 No. 2. 
 
 No. 3. 
 
 Special. 
 
 
 1 
 
 
 N.G 75 
 
 5 3 
 
 90 
 
 Randanite . . . . 20-8 
 
 I 
 
 I 
 
 Silica 3*3 
 
 48 
 
 65 
 
 8 
 
 MgCOs ! '4 
 
 
 
 
 
 i 
 
 CaC0 3 
 
 i '5 
 
 I 
 
 . 
 
 Ochre 
 
 '5 
 
 5 
 
 - 
 
 Slag 
 
 _ 
 
 4 
 
 
 In Spain mica is sometimes used as an absorbent, the 
 product containing 42 per cent, of nitroglycerine. 
 
 Dynamite had a great vogue when first introduced, but 
 is comparatively little used now as it has been largely 
 replaced by gelatinized explosives, although there is still 
 a fair demand for it. It freezes more easily than nitro- 
 glycerine, and in the frozen state is difficult to detonate. 
 It is very brisant in nature, and has the great dis- 
 advantage that in contact with water the nitroglycerine is 
 displaced. 
 
BLASTING EXPLOSIVES 
 
 97 
 
 In order to utilize the excess of oxygen present in nitro- 
 glycerine many powders have been made in which a com- 
 bustible absorbent has been used in place of guhr. Charcoal 
 made from cork has great absorptive power, and an explosive 
 consisting of 90 per cent, of nitroglycerine and 10 per cent, 
 of cork charcoal was manufactured at one time under the 
 name of Carbo-dynamite. It was too violent and expensive 
 for most purposes, however, and wood meal is more usually 
 employed. Atlas Powder, for example, consists of nitro- 
 glycerine 75 and wood meal 21 per cent., the balance being 
 made up of chalk with or without the addition of a little 
 sodium nitrate. 
 
 These wood meal Dynamites are deficient in oxygen, and 
 in order to supply this deficiency nitrates are added. This 
 class of explosive has become extremely popular in the 
 United States, where many blasting explosives are made 
 consisting of varying quantities of nitroglycerine, wood 
 meal, and sodium or ammonium nitrate. Sodium nitrate is 
 preferred to the potassium salt on account of its lower price, 
 but it is decidedly hygroscopic, and ammonium nitrate is 
 still more so, so that these explosives readily take up water 
 which in turn displaces the nitroglycerine. For this reason 
 they have never come into use in this country. 
 
 The following table gives a few examples of American 
 Straight Dynamites, but it must be borne in mind that the 
 figures are only average ones and considerable divergence is 
 often met with : 
 
 Dynamice. 
 
 70 per cent. 
 
 60 per cent. 
 
 50 per cent. 
 
 40 per cent. 
 
 30 per cent. 
 
 N.G. .. 
 
 7 
 
 60 
 
 50 
 
 40 
 
 3 
 
 W.M. 
 
 20 
 
 I6'5 
 
 T 4 
 
 12 
 
 IO 
 
 NaNO 3 
 
 7 
 
 22-5 
 
 35 
 
 47 
 
 59 
 
 Na 2 CO 3 ) 
 
 
 
 
 
 
 MgC0 3 
 
 3 
 
 I 
 
 I 
 
 i 
 
 i 
 
 CaCo 3 ) 
 
 
 
 
 
 
 Of these 40 per cent. Dynamite is probably the most 
 used, and is frequently known as Hercules Powder. 
 T. 7 
 
Carbonite. 
 
 Safety Nitro. 
 
 Stonite. 
 
 25 
 
 70 
 
 68 
 
 40-5 
 
 12*6 
 
 4 
 
 34 
 
 17-4 
 
 
 
 98 EXPLOSIVES 
 
 Other well-known American blasting powders of this 
 class are 
 
 N.G 
 
 W.M 
 
 NaNOg . . 
 
 KNO 3 8 
 
 Guhr ...... 20 
 
 Carbonate . . . . '5 
 
 An explosive of this class much used in South Africa is 
 I,igdyn, which has the composition 
 
 N.G 40 
 
 W.M. .. .+ 13 
 
 NaN0 3 45 
 
 Wheat flour . . . . . . . . 2 
 
 As will be seen, it is very similar in composition to the 
 American 40 per cent. Dynamite or Hercules Powder. 
 Similar mixtures are also used in the United States in 
 which about half the nitroglycerine has been replaced by 
 ammonium nitrate. These are known as Ammonia Dyna- 
 mites, and are made in several grades, 40 per cent. Ammonia 
 Dynamite, for example, containing about 20 per cent, of 
 nitroglycerine and the same amount of ammonium nitrate, 
 the balance being made up of sodium nitrate and wood meal. 
 
 Another favourite type of explosive used in America is 
 a kind of crude gunpowder to which nitroglycerine has been 
 added. The gunpowder base is composed of sulphur and 
 sodium nitrate, and powdered coal is frequently substituted 
 for charcoal. In some cases wood meal is added to assist 
 the absorption of the nitroglycerine. The following are 
 typical examples of this class of explosive : 
 
 N.G. 
 
 NaN0 3 . . 
 
 S .. 
 
 Charcoal . . 
 
 Coal .... 15 20 18 
 
 W.M. .... 5 
 
 Judson 
 
 Vulcan 
 
 Stump 
 
 Low 
 
 Powder. 
 
 Powder. 
 
 Powder. 
 
 Powder. 
 
 5 
 
 30 
 
 20 
 
 5 
 
 64 
 
 52*5 
 
 50 
 
 70 
 
 16 
 
 7 
 
 5 
 
 7 
 
 
 
 10 
 
 
 
 
 
BLASTING EXPLOSIVES 
 
 99 
 
 GELATINIZED EXPLOSIVES 
 
 In 1875 Nobel discovered that collodion cotton was 
 capable of dissolving in nitroglycerine to form a jelly. This 
 discovery, which was of an accidental nature and due to 
 Nobel having cut his finger and closed the wound with 
 collodion prior to his carrying out some experiments with 
 nitroglycerine, has had a very far-reaching effect on the 
 explosives industry, as it must be regarded not only as the 
 forerunner of all gelatinized blasting explosives, but also of 
 the nitroglycerine propellants. 
 
 Gelatinized explosives have several great advantages 
 over Dynamite. In the first place they dispense with all 
 inert ingredients, so that the whole of the explosive is of an 
 active nature. Hence much more powerful explosives can 
 be obtained, but at the same time these are easier to dope 
 down by the addition of wood meal and nitrates. The 
 jellies are far less sensitive to moisture than Dynamite 
 and can remain in contact with water for a reasonable 
 time without the nitroglycerine being displaced, and at 
 the same time they are less sensitive to shock. The labour 
 involved in making them up into cartridges is much less 
 than is the case with Dynamite and is also much safer, as 
 the somewhat dangerous dynamite pump is not required. 
 
 Up to the present all gelatinized explosives have con- 
 tained nitroglycerine, but jellies can also be obtained by 
 warming collodion cotton with certain nitroaromatic hydro- 
 carbons such as the so-called liquid trinitrotoluol. Un- 
 fortunately these jellies are very difficult to detonate and 
 are not very stiff, and so have not as yet found any applica- 
 tion. Future research, however, may enable these dis- 
 advantages to be overcome and thus render possible a 
 gelatinous explosive containing no nitroglycerine. 
 
 In manufacturing gelatinous explosives the dry collodion 
 cotton is weighed out into bags and carried to the nitro- 
 glycerine department, where the requisite quantity of 
 nitroglycerine is measured out, poured on to the collodion, 
 
100 
 
 EXPLOSIVES 
 
 and the whole mixed by hand. The thin liquid is then 
 carried in gutta-percha buckets with light wooden lids to 
 the mixing house, where it is transferred to water-jacketed 
 lead tanks. The water in the jacket is kept at about 50 C., 
 but the temperature of the explosive should not exceed 
 40-45 C. Gelatinization is allowed to proceed for some 
 hours, usually overnight, and the charge then transferred 
 to a mixing machine and mixed mechanically for an hour, 
 any dope, such as wood meal and potassium nitrate, being 
 added at this point. The machines are best jacketed with 
 warm water to prevent the jelly becoming too stiff, and are 
 usualty of the Werner and Pfleiderer type shown in Fig. 15, 
 
 FIG. 17. McRoberts Type Incorporating Machine (Plan). 
 
 p. 75. To avoid all chance of nitroglycerine entering the 
 bearings, however, the McRoberts mixer, shown diagramma- 
 tically in Figs. 17 and 18, is sometimes preferred. In this 
 case the explosive mixing pan is carried on a platform that 
 can be lowered so that the mixing arms clear the top of the 
 pan and allow it to be withdrawn. In charging the machine 
 the pan is withdrawn and the jelly loaded into it, after 
 which it is wheeled into place and the platform raised. 
 Stops are provided to prevent the pan being raised too high 
 and consequently the revolving arms coming in contact 
 with the bottom. Opinions differ as regards the merits 
 of the two types of machine, but the Werner and Pfleiderer 
 type is usually preferred and would seem to cause no more 
 
BLASTING 
 
 10 1 
 
 accidents than the McRoberts type. They are specially 
 built for the purpose, and precautions are taken to guard 
 against explosive entering the bearings. The McRoberts 
 machines have the advantage that the whole process of 
 gelatinization and incorporation can be carried out in the 
 same tank, thus avoiding transferring the jelly from the gela- 
 tinization tank to the incorporating machine ; but, on the 
 other hand, having to move a heavy article like the mixing 
 
 U 
 
 FIG. 1 8. McRoberts Type Incorporating Machine 
 (Sectional Elevation). 
 
 tank is decidedly objectionable. When incorporation is 
 complete the jelly is transferred to wooden boxes and carried 
 to the cartridge huts, where it is put through " sausage " 
 machines and the resulting cord cut up with double-bladed 
 brass knives and then wrapped in parchment paper. 
 
 These " sausage " machines (Figs. 19 and 20) are con- 
 structed of gun-metal in such a way that all bearings are 
 external so that no explosive can get into them, and sufficient 
 clearance is left where the shaft enters to avoid friction. 
 
lo: 
 
 EXPLOSIVES 
 
 They are provided with internal ribs to prevent the jelly 
 from merely being revolved, and are always worked by hand. 
 The conical type (Fig. 19) was the original type used, but 
 the circular type (Fig. 20) is now generally preferred, as it 
 puts less pressure on the explosive. In making the usual 
 size of cartridge, viz. f in. or } in., two nozzles are used except 
 
 FIG. 19. Sausage Machine for Gelatinized Explosives. 
 
 in the case of very stiff jellies such as Blasting Gelatine, 
 when only one is used. 
 
 Gelatinized explosives, like all explosives containing 
 nitroglycerine, have a great tendency to freeze, and in this 
 
 FIG. 20. Sausage Machine for Gelatinized Explosives. 
 
 condition are difficult to detonate. Many accidents have 
 been caused by frozen explosives, as some of the cartridges 
 in the shot hole may escape detonation and remain mixed 
 with the mineral brought down. Also it is difficult to 
 persuade miners to thaw frozen explosives in a warming 
 pan, so that many fatalities have occurred through their 
 being thawed over a fire or by other improper means. labo- 
 ratory experiments point to frozen explosives being less 
 
BLASTING EXPLOSIVES 103 
 
 sensitive to shock than unfrozen ones, but these experi- 
 ments are quite misleading owing to the small quantities 
 used. Experience under working conditions shows most 
 decidedly that in the frozen state they are more sensitive, 
 and not a few accidents have been caused through miners 
 trying to make a hole in a frozen cartridge in which to 
 insert a detonator. 
 
 For this reason many attempts have been made to add 
 substances to the nitroglycerine which will lower its freezing- 
 point sufficiently to allow it to remain liquid at ordinary 
 working temperatures. The freezing-point coefficient of 
 nitroglycerine is 70-5, but Raoult's law only holds good for 
 very dilute solutions, and these are of but little value from 
 a technical point of view. 
 
 Non-freezing explosives were originally made by adding 
 nitrobenzole or nitrotoluol to the nitroglycerine, but un- 
 fortunately these greatly decrease the power and render 
 detonation more difficult. At present trinitrotoluol is 
 generally used and is frequently applied in the form of the 
 so-called liquid T.N.T., as this mixes more readily with the 
 nitroglycerine than solid T.N.T. 
 
 In Great Britain, where very low temperatures are not 
 encountered, the amount used is 5-10 per cent, of the weight 
 of nitroglycerine, but in America and on the Continent 
 20-25 per cent, is frequently used. 
 
 In Germany explosives are made with a mixture of 
 nitroglycerine and dinitroglycerine, tetranitrodiglycerine or 
 dinitrochlorhydrin, and in France dinitroglycol is used. As 
 would be expected from their lower molecular weight, these 
 are more effective than nitroaromatic hydrocarbons. 
 Unfortunately the majority of suitable substances with 
 low molecular weight are too volatile, but nitromethane 
 (B.P. 101 C.) has been proposed, as 10 per cent, reduces 
 the freezing-point of nitroglycerine to 15 C. Its cost, 
 however, is against its use at present. 
 
 Dinitroacetyl glycerine and dinitroformin (D.R.P. 
 209,943) have also been proposed. The latter is very 
 easily made by heating glycerine with half its weight of 
 
104 EXPLOSIVES 
 
 oxalic acid to 100 C. and finally to 150 C., and then nitrating 
 the product. The oil thus obtained contains 33 per cent, 
 of dinitroformin dissolved in nitroglycerine and is almost 
 unfreezable. 
 
 The three standard gelatinized explosives in use in Great 
 Britain are Blasting Gelatine, Gelatine Dynamite, and 
 Gelignite, the average composition of which is shown in 
 the following table : 
 
 N.G. C.C. W.M. KN0 3 . 
 
 Blasting Gelatine . . 92 8 
 
 Gelatine Dynamite 75 5 5 J 5 
 
 Gelignite . . . . . . 60 4 8 28 
 
 Of these Gelignite is far the most used, and may in fact 
 be regarded as the standard high explosive. 
 
 Blasting Gelatine, which forms a stiff translucent jelly, 
 is too brisant for most purposes, although used for hard 
 rock. It is the most powerful explosive on the market, 
 but has several serious drawbacks. In the first place it 
 hardens on keeping, and at the same time becomes very 
 insensitive so that it can only be exploded by means of an 
 extra heavy detonator. It also has a great tendency to 
 sweat or exude nitroglycerine, especially if it has been 
 frozen and thawed several times. The sweating is some- 
 times quite excessive, and the nitroglycerine may actually 
 be seen running out of the cases. Needless to say such 
 Blasting Gelatine is very dangerous. The exudation trouble 
 is very noticeable with explosive that has been exported 
 to the antipodes, and is probably accentuated by the passage 
 through the tropics, hundreds of tons being condemned 
 every year in Australia on account of exudation. It is 
 very difficult to obtain a good Blasting Gelatine that will 
 not sweat and probably most depends on the quality of 
 collodion used. This should contain about 12 per cent, 
 of nitrogen, should have been nitrated at a low temperature 
 and only washed in hot water and not boiled. Finally, it 
 should not have been over-pulped as this, like boiling, 
 adversely affects its gelatinizing powers. Other gelatinized 
 explosives such as Gelatine Dynamite and Gelignite also 
 
BLASTING EXPLOSIVES 
 
 105 
 
 have a tendency to sweat, but these give little trouble as 
 the wood meal holds back the nitroglycerine. 
 
 Since 1914, when the outbreak of war made potash 
 supplies scarce, Gelatine Dynamite and Gelignite have been 
 made with sodium nitrate in place of the potassium salt. 
 
 Nitroglycerine is slightly gelatinized when used for a 
 large number of explosives, as by thickening it without 
 actually forming a jelly its tendency to be displaced by 
 water is lessened. 
 
 In the United States many grades of Gelatin or Gelatin 
 Dynamite are manufactured, in some of which the wood 
 meal is partly replaced by flour and sulphur. They usually 
 contain one per cent, of calcium carbonate, and have a 
 nitroglycerine content of from 20 to 60 per cent. 
 
 In France gelatinized explosives are known as Gommes, 
 Dynamites Gelatines, or simply Gelatinees, and are manu- 
 factured in great variety, both potassium and sodium 
 nitrate being used. The following table shows a few typical 
 examples : 
 
 
 N.G. 
 
 C.C. 
 
 KN0 3 
 
 NaNO 3 
 
 W.M. 
 
 Gomme extraforte 
 
 92 
 
 8 
 
 _. 
 
 _ 
 
 
 
 Gomme B . . 
 
 86 
 
 5 
 
 4 
 
 
 
 5 
 
 Gomme G . . 
 
 83 
 
 5 
 
 
 IO 
 
 2 
 
 Gomme ^B 
 
 74 
 
 6 
 
 *5'5 
 
 . - 
 
 4 '5 
 
 Gelatinee iB 
 
 64 
 
 3 
 
 
 24 
 
 8 
 
 Gelignite . . 
 
 60 
 
 3 
 
 27 
 
 
 10 
 
 D)^namite Gelatinee 2C 
 
 43 
 
 2 
 
 4* 
 
 " 
 
 4 
 
 Dynamite No. 4 and Dynamite No. 5 are both jellies 
 containing sodium nitrate, the former containing 59 and 
 the latter 48 per cent, of nitroglycerine. 
 
 The Belgian Forcites are very similar in nature : 
 
 
 N.G. 
 
 C.C. 
 
 KN0 3 
 
 NaNOg 
 
 W.M. 
 
 MgCOg 
 
 Forcite extra 
 
 74 
 
 6 
 
 14 
 
 __ 
 
 5 
 
 I 
 
 Forcite superieure 
 Forcite No. i 
 
 64 
 49 
 
 3 
 
 2 
 
 
 24 
 3^ 
 
 8 
 13 
 
 I 
 
 Some Belgian Forcites also contain ammonium nitrate. 
 
106 EXPLOSIVES 
 
 CHLORATE AND PERCHLORATE MIXTURES 
 
 The formation of chlorates from the metallic chloride 
 and oxygen is an endothermic reaction, and consequently 
 chlorates in themselves are capable of explosion 
 
 KC1 + 30 = KC1O 3 - ii -9. Cal. 
 NaCl + 30 = NaC10 3 - 13-1 Cal. 
 BaCl 2 + 60 = Ba(C10 3 ) 2 - 25-9 Cal. 
 
 The explosion of a chlorate is brought about by heat, 
 or by heat in conjunction with shock, and although the 
 explosion is usually not violent several serious accidents 
 have occurred. The instability of chlorates renders chlorate 
 mixtures very sensitive, and in most countries the use of 
 chlorates in conjunction with sulphur is prohibited. In 
 Great Britain the only form of chlorate explosive that is 
 authorized is Cheddite, the chlorate in this case being pro- 
 tected and rendered less sensitive by oil. In other countries, 
 however, Sprengel explosives are permitted, in which the 
 chlorate and the combustible matter are only brought in 
 contact with one another immediately before charging the 
 bore hole. Chlorates must never be used in conjunction 
 with ammonium salts, such as ammonium nitrate, as under 
 these conditions double decomposition is liable to take place 
 with the production of the highly unstable ammonium 
 chlorate, a salt liable to spontaneous explosion 
 
 KC10 3 + AmN0 3 = KNO 3 + AmClO 3 
 
 Perchlorates, on the other hand, are much more stable 
 than chlorates, as their formation from the chloride and 
 oxygen is an exothermic reaction 
 
 KC1 + 40 = KC10 4 +7-9 Cal. 
 NaCl + 40 = NaClO 4 + 2-4 Cal. 
 BaCl 2 + 80 - Ba(C10 4 ) 2 + 4-3 Cal. 
 
 Ammonium perchlorate is also stable, but is capable of 
 explosion although only with difficulty. Its detonation is 
 represented by the equation 
 
 NH 4 C1O 4 = C1+O 2 + N + 2H 2 O (gaseous) + 38-3 Cal. 
 
BLASTING EXPLOSIVES 107 
 
 It is about as sensitive to blows as picric acid, but the 
 explosion does not usually spread throughout the mass. 
 
 Chlorates are invariably manufactured by the electrolysis 
 of chlorides, and on further electrolysis pass intoperchlorates. 
 For this reason commercial perchlorates are liable to be 
 contaminated with chlorate, and such contamination renders 
 them quite unsuitable for use in the manufacture of explo- 
 sives. This is particularly so in the case of ammonium 
 perchlorate, as the presence of sodium or potassium chlorate 
 would render the product liable to double decomposition 
 with the production of ammonium chlorate. 
 
 Of the chlorates the potassium salt is the most used, as 
 the sodium salt is very soluble and deliquescent and con- 
 sequently difficult to obtain pure. The latter, however, 
 enters into the composition of some French Cheddites, and 
 barium chlorate is used to some extent as an ingredient in 
 fireworks. Of the perchlorates the almost insoluble potassium 
 salt is most used, although the ammonium salt can be obtained 
 pure at a reasonable price.* This latter salt has scarcely 
 received the attention it deserves in this country, but now 
 that it has been manufactured for war purposes it will 
 probably receive greater attention. It has the advantage 
 of giving only gaseous products, but unfortunately these 
 include chlorine. Chlorine fume can be prevented by adding 
 alkali nitrate in sufficient quantity to provide a base to 
 combine with the chlorine but such mixtures are liable to 
 deliquesce owing to the formation of ammonium nitrate 
 and alkali perchlorate by double decomposition. 
 AmC10 4 + KN0 3 = KC1O 4 + AmNO 3 
 
 For Permitted Explosives, however, the base might be 
 added in the form of an oxalate, this acting at the same 
 time as the " cooler," or the base might be added in the 
 form of a salt of a suitable organic acid, the organic 
 part of the molecule providing the requisite combustible 
 matter. 
 
 * In 1918 the cost of manufacture of ammonium perchlorate was 99 
 per ton as compared with ^45 per ton for ammonium nitrate (C.T.J., 
 1919, p. 162). 
 
108 EXPLOSIVES 
 
 Sprengel Explosives. These consist of cartridges of 
 potassium chlorate, which immediately before use are dipped 
 into a liquid combustible. They are not authorized in Great 
 Britain, as the process of dipping is a manufacturing opera- 
 tion within the meaning of the Act and can therefore only be 
 carried out on licensed premises and under " danger " con- 
 ditions. These explosives are used, however, to a consider- 
 able extent on the Continent and in America, but have the 
 disadvantage that the penetration of the combustible liquid 
 is very uneven, so that uncertain results are obtained. In 
 France " Explosif 63 " or " Promethee " is much used, and 
 consists of cartridges containing 80, 90 or 95 per cent, of 
 potassium chlorate mixed with 20, 10 or 5 per cent, of 
 manganese dioxide, and dipped into a mixture containing 
 50 per cent, of nitrobenzole and 50 per cent, of turpentine 
 or naphtha, or a mixture of these. The American explosive, 
 Rack- a- Rock, is very similar. 
 
 lyiquid air explosives, "Oxyliquits," may be mentioned 
 at this point as they are of the Sprengel type although con- 
 taining no chlorate. They consist of a solid organic absorbent 
 such as cork dust, on which liquid air or oxygen is poured just 
 before use. They were used in the construction of the Simplon 
 tunnel, and are said to have been widely used in Germany 
 for general blasting purposes during the war, but are not 
 likely to come into general use, as liquid air has obvious 
 disadvantages and inconveniences. Also the density of the 
 explosive is low so that the cost of making bore holes is 
 excessive. lyiquid air, however, is cheap, especially where 
 extensive mining operations are in progress and large 
 quantities of explosive required. The great advantage of 
 liquid air explosives lies, perhaps, in the absence of danger 
 from misfires or incomplete detonation. With ordinary 
 explosives accidents due to misfires necessitating the with- 
 drawing of the charge or insertion of a new detonator are 
 not uncommon, and incomplete detonation in which 
 cartridges or parts of cartridges remain in the debris are 
 apt to lead to accidents through being struck with a 
 pick or shovel. With liquid air explosives these dangers 
 
BLASTING EXPLOSIVES 109 
 
 do not exist, as the air rapidly evaporates. They are 
 not authorized in Great Britain, for the same reason 
 that chlorate explosives of the Sprengel class are not 
 authorized. 
 
 Cheddites. These were discovered by Street, and 
 derive their name from Chedde, the town in France where 
 chlorates were principally manufactured. They consist 
 usually of potassium chlorate mixed with a fatty oil, usually 
 castor oil, which has been thickened by dissolving aromatic 
 nitro-compounds in it, although some French Cheddites 
 are made with paraffin. As nitro-compounds a mixture of 
 mononitronaphthalene and dinitrotoluol is generally used, 
 and although the original Cheddite contained 2 per cent, 
 of picric acid this was soon replaced by dinitrotoluol. In 
 their manufacture the nitro-compounds are first dissolved 
 in the oil at a temperature of 70 C. and the finely ground 
 dry chlorate added slowly. The whole is well mixed by 
 hand, first hot and then in a semi-cold condition, sifted and 
 then compressed into cartridges in wooden moulds. In 
 order to obtain a satisfactory explosive the degree of com- 
 pression must be carefully controlled, especially as Cheddites 
 are usually rather easily compressed. If the density is too 
 low full power is not developed, whereas if too high detona- 
 tion becomes difficult or impossible. For this reason con- 
 siderable care is required in making up the cartridges, as 
 some Cheddites are very readily compressed, especially 
 those made with sodium chlorate. The following table 
 shows the velocity of detonation of three different Cheddites 
 at different densities, the experiments being carried out in 
 copper tubes 22 mm. in diameter. The explosives used had 
 the composition 
 
 Type 6o 4 . P. S. 
 
 KC10 3 .... 75 90 
 
 NaClO 3 .... 89 
 
 M.N.N. .. .. i 
 
 D.N.T 15 
 
 Paraffin 10 n 
 
no 
 
 EXPLOSIVES 
 
 Temperature. 
 
 3-4 
 
 TYPE 6o 4 
 
 Density. 
 
 81 
 
 i '39 
 1-48 
 
 1-62 
 EXPI,OSIF P 
 
 Temperature. 
 
 3C. 
 
 15 C. 
 
 Temperature. 
 
 17 C. 
 
 EXPI,OSIF S 
 
 Density. 
 
 81 
 
 92 
 
 i'45 
 1-56 
 
 Velocity. 
 Metres per sec. 
 
 2457 
 3045 
 3156 
 
 3099 
 2820 
 
 Velocity. 
 Metres per sec. 
 
 2137 
 3044 
 3185 
 3621 
 
 3475 
 Incomplete 
 
 2940 
 
 3457 
 
 3565 
 
 Incomplete 
 
 Velocity. 
 Metres per sec. 
 
 2191 
 
 2475 
 2966 
 2940 
 2688 
 Incomplete 
 
 The density acquired by the same explosives under 
 different pressures is shown in the following table, the 
 pressure being given in kilograms per cm. 2 : 
 
 Type 6o 4 . 
 
 Explosif P. 
 
 Explosif S. 
 
 Pressure. 
 
 Density. 
 
 Pressure. 
 
 Density. 
 
 Pressure. 
 
 Density. 
 
 '7 
 
 1-25 
 
 *7 
 
 9 
 
 02 
 
 92 
 
 1*4 
 
 1-31 
 
 1*6 
 
 '99 
 
 3 
 
 1*29 
 
 1-6 
 
 I-38 
 
 5'9 
 
 I'2I 
 
 6 
 
 1*33 
 
 2-1 
 
 I '40 
 
 8-0 
 
 1-29 
 
 '7 
 
 1*39 
 
 3 -2 
 
 1*46 
 
 2O'O 
 
 1*37 
 
 *'4 
 
 1-47 
 
 4-8 
 
 1*5* 
 
 58'0 
 
 i'59 
 
 3- 2 
 
 i'55 
 
BLASTING EXPLOSIVES 
 
 in 
 
 The following table shows the composition of the chief 
 French Cheddites : 
 
 
 KC10 3 . 
 
 NaCI0 3 . 
 
 Castor oil. 
 
 M.N.N. 
 
 D.N.T. 
 
 Paraffin. 
 
 Fype 60 
 
 80 
 
 __ 
 
 6 
 
 12 
 
 2 
 
 
 
 Fype 41 
 
 80 
 
 
 
 8 
 
 12 
 
 
 
 
 
 D 2 
 
 79 
 
 
 
 5 
 
 I 
 
 15 
 
 
 
 3 4 
 
 90 
 
 
 
 
 
 
 
 
 
 10 
 
 _)g 
 
 
 79 
 
 5 
 
 1 
 
 16 
 
 ~ 
 
 Of these O 5 is the most brisant and O 3 the least. 
 
 Cheddites are also authorized and used in Great Britain, 
 but the demand is not great. Thus in 1910, out of a total 
 consumption of 15,000 tons of blasting explosives of all 
 classes, only 60 tons were Cheddite. 
 
 In Germany mixtures of chlorates and resin are used to 
 some extent, e.g. Silesia No. 4 consists of 80 per cent, of 
 potassium chlorate and 20 per cent, of resin. Some years 
 ago attempts were made to introduce similar explosives 
 into Great Britain under the name of Steelite. These were 
 composed of potassium chlorate and resin which had been 
 previously oxidized by nitric acid. They never came into 
 general use, although Colliery Steelite was on the old " Per- 
 mitted " list, but failed at the Rotherham test. It had the 
 composition 
 
 KC10 3 .. 
 Oxidized resin 
 Castor oil 
 Moisture 
 
 .. 23-5-26-5 
 
 0-1 
 
 Perchlorates have been suggested as a substitute for 
 nitre in black powder, but have not been used to any extent. 
 A British explosive, Polarite, was introduced some years 
 ago as a substitute for Gelignite and seemed to consist of 
 a non-freezing Gelignite containing T.N.T. in which potassium 
 perchlorate was used in place of nitre. The German explo- 
 sive, Permonite, was on the old " Permitted " list in Great 
 
H2 EXPLOSIVES 
 
 Britain, but failed to pass the Rotherham test. It had the 
 composition 
 
 KC10 4 31-34 
 
 N.G 3-4 
 
 C.C -5-1 
 
 AmNO 3 39-43 
 
 T.N.T 11-13 
 
 Starch . . . . . . . . 5-9 
 
 W.M. ^ 1-5-3-5 
 
 Glycerine ) 
 
 Gelatine ( " " I '5-3'5 
 
 The French Government experimented with two Cheddites 
 made with ammonium per chlorate and having composition 
 
 No. i. No. 2. 
 
 AmClO 4 82 50 
 
 D.N.T 13 15 
 
 NaNO 3 30 
 
 Castor oil . , 5 5 
 
 but did not authorize them as they presented no advantages 
 over existing Cheddites. The use of castor oil, however, in 
 the presence of perchlorate would seem useless as, unlike 
 the chlorates, they are not sensitive to friction. 
 
 The Belgian Yonckites are ammonium perchlorate ex- 
 plosives for use in coal mines, and consist of ammonium 
 perchlorate mixed with sodium and ammonium nitrate, 
 trinitrotoluol and sodium chloride. 
 
 The Swedish explosive, Blastine, is composed of ammo- 
 nium perchlorate, sodium nitrate, D.N.T. and paraffin. 
 Pernitral was the name of an explosive authorized in this 
 country a few years ago, but the manufacture of which 
 does not seem to have been taken up. It had the 
 composition 
 
 AmClO 4 40 
 
 NaNO 3 30 
 
 Solid T.N.T 10 
 
 liquid T.N.T 10 
 
 Al powder . . . . . . . . 10 
 
BLASTING EXPLOSIVES 113 
 
 Samples tested by the author seemed to be somewhat 
 more powerful than Blasting Gelatine, but unfortunately a 
 No. 8 detonator was required in order to obtain the full 
 effect. 
 
 AMMONIUM NITRATE EXPLOSIVES 
 
 Explosives consisting of ammonium nitrate in conjunc- 
 tion with combustible matter, a nitroaromatic hydrocarbon 
 for preference, were first proposed by Favier in 1885. They 
 have the advantage of being cheap and safe to manufacture 
 and use, but have the serious disadvantage of being very 
 hygroscopic, so that even when put up in carefully waxed 
 cartridges they take up moisture rapidly and become unfit 
 for use in a few weeks. As a class they have extremely 
 low temperatures of explosion, and for this reason are largely 
 used as coal mine explosives (see Section V.), but are also 
 used to some extent for general blasting purposes. Their 
 use for general purposes is likely to extend in the near future 
 owing to the low price at which they can be manufactured. 
 The best-known British explosives of this class are discussed 
 in the next section, but the following have been used to a 
 considerable extent in Germany 
 
 Astralit. Fulmenit. 
 
 AniNO 3 81 82-5 
 
 T.N.T ii ii 
 
 Paraffin Oil . . i i 
 Meal . . . . . . 2 
 
 Coal i 
 
 N.G 4 
 
 Charcoal . . . . . . 1-5 
 
 Guncotton 4 
 
 Westfalit fur Kohle. 
 
 AmNO 3 . . . . 91 
 
 KNO 3 .. .. 4 
 
 Resin . . . . . . 5 
 
 For ordinary blasting purposes it has been proposed to 
 increase the power of ammonium nitrate explosives by the 
 T. 8 
 
H4 EXPLOSIVES 
 
 addition of aluminium powder, the heat of combustion of 
 which is very high 
 
 2A1 + 3O 2 = 2A1 2 O 3 + 760 Cal. 
 
 The best known of these explosives is Ammonal, which 
 for ordinary blasting purposes contains about 25 per cent, 
 of aluminium powder, the balance being ammonium nitrate 
 and T.N.T. Ammonals containing much less aluminium, 
 however, are also manufactured, for example 
 
 AmNO 3 . . . . 94 93 88 81 
 
 Al 3 3 8 15 
 
 C 3 44 
 
 T.N.T 4 
 
 Gesteins-Westfalit contains dinitrotoluol, and has the 
 composition 
 
 AmNOg 84-5 
 
 Al 3'5 
 
 D.N.T 12-0 
 
 In all explosives of this nature the aluminium is added 
 in the form of a fine powder, but too fine a state of sub- 
 division is to be avoided, as very finely powdered aluminium 
 oxidizes readily in the air. As a rule the commercial 
 " aluminium bronze " is used. This is manufactured by 
 rolling aluminium into very thin sheets, which are then cut 
 into strips and ground. 
 
 Very similar explosives in which calcium silicide is used 
 in place of aluminium are also manufactured, Sabulite 
 being an explosive of this class. The use of ferrosilicon has 
 also been proposed (A.P. 1,277,043), although it does not 
 seem to have come into use. 
 
 In making up ammonium nitrate explosives into cart- 
 ridges two methods are used. If loaded by hand the paper 
 is rolled on a wooden rod of suitable size and one end folded 
 in and closed. The paper cylinder thus formed is then 
 inserted closed end downwards in an aluminium tube fixed 
 in a block of wood, and the explosive fed in through an 
 aluminium funnel and well rammed with a wood or aluminium 
 
BLASTING EXPLOSIVES 
 
 rod. This method has little to recommend it except that 
 the plant can be bought for a few shillings. A much more 
 satisfactory method is to use a helix machine very similar 
 to the " sausage " machines used for gelatinized explosives, 
 the machine being made to work against a suitable resistance 
 in order to pack the powder evenly and firmly. A simple 
 machine of this nature for use with hand power is shown in 
 Fig. 21. The explosive is fed in through the hopper and the 
 
 FIG. 21. Cartridge Filling Machine for Ammonium Nitrate Explosives. 
 
 paper cylinder held against the nozzle by means of a cord 
 and weight. As the loading proceeds the paper is forced 
 backwards away from the nozzle, an adjustable stop being 
 provided to indicate when loading is complete. By varying 
 the weight the explosive can be packed more or less tightly 
 at will. In Germany similar machines are used that are 
 power-driven, but these as a rule are vertical. 
 
 TONITK 
 
 This was formerly much used for blasting purposes, and 
 consisted of compressed guncotton containing from 25 to 40 
 per cent, of a nitrate, usually barium or potassium nitrate. 
 Its interest is now chiefly historical. 
 
 LITERATURE 
 DYNAMITE 
 
 Two interesting accidents which have occurred in the manufacture of 
 Dynamite are described in StR., 145, 184; 
 
Ii6 EXPLOSIVES 
 
 GELATINIZED EXPLOSIVES 
 
 The following accounts of accidents are instructive: S.R., 151, 201. 
 For notes on the exudation of nitroglycerine from Blasting Gelatine, 
 see A.E., 1914. 
 
 CHLORATE EXPLOSIVES 
 
 Much information on the properties of Cheddites will be found in 
 P.S., xi., 22; xii., 123; xiii., 29, 144, 282; xiv., 26, 33, 192; xv., 135, 
 212, 247 ; xvi., 66. 
 
 Two accidents in this country are described in S.R., 135 and 185. 
 
 AMMONIUM NITRATE EXPLOSIVES 
 E.P. 2139"; 16,277; A.P. 1,277,043. 
 
 BLASTING 
 O. Guttmann, " Blasting," London, 1906. 
 
SECTION V. SAFETY COAL MINE 
 EXPLOSIVES 
 
 THE use of explosives in coal mines is always attended by 
 the risk of firing the mine gases and coal dust. This ignition 
 may be due to some extent to the vibration set up by the 
 shock of the explosion, but the greatest risk is due to local 
 rise in temperature caused by the flame of the explosion or 
 by the adiabatic compression of the gas. Air, for example, 
 when adiabatically compressed to 60 kg. per cm. 2 suffers a 
 rise in temperature of 670 C., whereas at 100 kg. per cm. 2 it is 
 820 C., and at 200 kg. per cm. 2 it is 1060 C. A mixture of air 
 and fire damp will inflame at 650 C., but at this temperature 
 there is a period of induction of about 10 seconds, although 
 this period grows progressively shorter with increasing 
 temperature. Under working conditions in a mine rapid 
 diffusion takes place so that although locally the temperature 
 may rise far above the point of inflammation, the diffusion of 
 the overheated gases cools them before the period of in- 
 duction is complete, and hence no explosion results. Of 
 course, there is a limiting temperature above which the 
 period of induction is so short that inflammation takes place 
 before diffusion has had time to lower the temperature below 
 the ignition point, and for safety it is consequently necessary 
 to select explosives and conditions of shot firing in such a 
 way that the local rise in temperature is not excessive. 
 The problem is a difficult one, as mine conditions are very 
 variable, and the chief danger arises from abnormal cases, 
 such as blown-out shots. Consequently the tests applied 
 are of an empirical nature, although designed as far as possible 
 to represent actual working conditions. Usually they 
 imitate what might happen in a mine under the worst possible 
 conditions. 
 
 In order to investigate the problem and lay down rules 
 
n8 
 
 EXPLOSIVES 
 
 for blasting in gassy mines, almost all civilized countries 
 in which coal mining is an important industry have appointed 
 Commissions. The first of these was appointed in France 
 in 1877, the British Commission being appointed two years 
 later, and the Prussian Commission in 1881. The Belgian 
 and Austrian Commissions were both set up at a rather later 
 date. The result of these Commissions has been the setting 
 up of galleries in which explosives can be fired into a gas 
 mixture, or into air or gas laden with coal dust, and the 
 laying down of regulations limiting the composition of the 
 explosives which may be used, the weight that may be used 
 in any one blast, and the conditions under which blasting 
 may be carried out. 
 
 Explosive. 
 
 Density. 
 
 Velocity of Length of Duration ! **"" 
 Detonation. Flame. of Flame, i R ^tio 
 
 (KN0 3 
 
 75 
 
 
 
 G.P. C. 
 
 12 
 
 I-0 4 
 
 200-300 i 10 77 1:330 
 
 Is. 
 
 13 
 
 
 
 R r /N.G. 
 
 B - G - (c.c. 
 
 92 
 8 
 
 I-6 3 
 
 7700 224 9*72 i : 883 
 
 Dynamite {Q jjl 
 
 75 
 25 
 
 1-58 
 
 6818 228 8-31 1:620 
 
 (N.G.* 
 
 63|5 
 
 
 i 
 
 Ic.c. 
 
 Gelignite }NaNO 3 
 
 27 
 
 I-6 7 
 
 6210 150 1*23 i : 101 
 
 (W.M. 
 
 8 
 
 
 
 
 AmNO 3 
 
 80 
 
 
 
 
 N.G. 
 
 3'8 
 
 
 
 Donarite 
 
 C.C. 
 
 '2 
 
 I-3I 
 
 3930 69 -40 1:15 
 
 
 T.N.T. 
 
 I2'O 
 
 
 4137 
 
 
 Flour 
 
 4 -0 
 
 
 (confined) 
 
 
 
 AmNO 3 
 
 80-3 
 
 
 
 
 
 KN0 3 
 
 5' 
 
 
 
 Ammon- 
 Carbonite 
 
 N.G. 
 C.C. 
 
 4-0 
 
 2 
 
 I'll 1753 51 '32 
 
 1:7-4 
 
 
 Coal 
 
 Starch 
 
 6-0 
 4*5 
 
 
 3*95 
 (confined) 
 
 
 
 AmNO 3 92 
 
 2137 
 
 Thunderite 
 
 T.N.T. 
 
 4 
 
 1-07 3654 -33 
 
 
 
 
 Flour 
 
 4 
 
 
 (confined) 
 
 
 
 
 
 i 
 
 
 Bichel has investigated the duration of flame by firing 
 explosives at night and photographing the flame through a 
 quartz lense on a moving film. He finds that in all cases the 
 flame outlasts the time of detonation, and has named the 
 
SAFETY COAL MINE EXPLOSIVES 119 
 
 ratio duration of detonation : duration of flame the " after- 
 flame ratio." He finds that safety explosives have a very 
 short flame duration, and consequently a high after-flame 
 ratio, the table in the preceding page showing some of his 
 figures, velocity of detonation being given in metres per 
 second, duration of flame in thousandths of a second and 
 length of flame in millimetres. The experiments were carried 
 out with 100 grams of explosives made up in cartridges of 
 30 mm. diameter, and fired from a gun similar to those used 
 in the official testing galleries. 
 
 In the American testing station at Pittsburg several 
 explosives were analyzed and the flame from 200 grams 
 photographed, and the heat liberated measured. The 
 following very interesting figures were obtained. The heat 
 liberated is expressed in major calories per kilogram, and 
 the duration of flame in milliseconds 
 
 Composition. 
 
 Weight of 
 wrapper per 
 100 grams. 
 
 Per cent. CO 
 in products 
 of Explosive. 
 
 Heat Duration 
 liberated. of Flame. 
 
 D.N.T. 
 
 17-85 . 
 
 
 
 ; 
 
 M.N.N. 
 
 1*30 
 
 
 
 l 
 
 Castor oil 
 
 5*32 . 
 
 5 
 
 41 
 
 1065 '196 
 
 KC10 3 
 
 75'36 . 
 
 
 
 
 
 H 2 
 
 17 . 
 
 
 
 
 
 N.G. 
 
 8-13 
 
 
 
 
 
 M.N.T. 
 
 3'57 
 
 
 
 
 
 Castor oil 
 
 81 . 
 
 
 
 
 
 N.C. 
 
 56 
 
 6'5 
 
 5*9 
 
 1169 
 
 279 
 
 AmNO 3 
 
 82-11 . 
 
 
 
 
 W.M. 
 
 4-30 . 
 
 
 
 
 
 H 2 O 
 
 52 - 
 
 
 
 
 
 KN0 3 
 
 65'3i 
 
 
 
 
 
 C. 
 
 19-52 
 
 
 
 
 
 S. 
 
 2-63 . 
 
 None 
 
 4 
 
 622*7 i3 
 
 Paraffin 
 
 3' 35 
 
 
 
 
 Starch 
 
 8-73 
 
 
 
 
 This last explosive would appear to be Bobbinite, and 
 in view of its great flame duration it is scarcely surprising 
 that it does not pass the Rotherham Test. 
 
 Will has also studied the duration of flame by photo- 
 graphic methods. He took his photographs on a drum 
 
120 EXPLOSIVES 
 
 covered with a sensitive film over which was laid an opaque 
 screen, in which a series of equidistant slits were cut, the 
 whole being rapidly rotated behind a fixed opening. By 
 this means he obtained a species of cinematograph photo- 
 graphs in the form of a- series of bands. He found that with 
 explosives deficient in oxygen the flame dies away very 
 rapidly and then revives, the secondary flame being of much 
 greater duration than the primary flame. This secondary 
 flame is due to the carbon monoxide escaping from the bore 
 hole and burning in contact with atmospheric oxygen, and 
 can be prevented by the addition of a few per cent, of an 
 alkali salt, the salts of the alkali metals being far more 
 effective than the salts of the alkali earths or of lead. 
 
 The first proposal for rendering explosives used in fiery 
 mines safe by reducing the temperature of explosion was due 
 to MacNab, who in 1873 suggested placing a cartridge of 
 water immediately above the charge in the bore hole. This 
 suggestion was soon followed by others, in which wet moss 
 or a jelly containing 90 per cent, of water was substituted for 
 the inconvenient cylinder of water, but none of these met 
 with any great success, partly owing to the tendency of the 
 miners to omit using them, and partly owing to the contents 
 being blown about in large lumps, and not being sufficiently 
 pulverized by the explosion. The next step was the use of 
 salts containing water of crystallization, such as magnesium 
 sulphate, as these could be incorporated with the explosive 
 itself, and this method is still used to a slight extent, although 
 almost all modern safety explosives rely on the chlorides of 
 sodium, potassium or ammonium as " coolers," the cooling 
 being brought about by the heat absorbed by the volatiliza- 
 tion, and to some extent also by the dissociation of these 
 salts. Ammonium chloride has the disadvantage that it 
 is apt to spoil the detonation of the explosive, and it must be 
 used in conjunction with at least one equivalent of an alkali 
 nitrate to provide a base with which the free chlorine 
 liberated during the explosion may combine. It also 
 renders the explosive hygroscopic as double decomposition 
 takes place with the production of ammonium nitrate 
 
SAFETY COAL MINE EXPLOSIVES 121 
 KN0 3 + NH 4 C1 = KC1 + NH 4 N0 3 
 
 A salt containing water of crystallization when used in 
 conjunction with ammonium nitrate is also objectionable, 
 as the nitrate is apt to rob it of its water and to become liquid 
 by solution. 
 
 In Great Britain explosives that may be used in fiery 
 mines are known as " Permitted Explosives/' in the United 
 States as " Permissible Explosives," in France as " Explosifs 
 de Surete," or " Explosifs Anti-grisouteuses," in Belgium as 
 "Explosifs S. G. P." ("Sure Grisou Poussieres "), and in 
 Germany as " Wetter- or Wettersichere Sprengstoffe." 
 
 Test Galleries. The German gallery is at Gelsenkirchen- 
 Schalke, and is 35 metres long. It is elliptical in section, and 
 has a sectional area of two square metres, the major axis 
 being vertical and 1*8 metres long, and the minor axis 
 i "35 metres long. Shots are fired into an explosion chamber, 
 formed by partitioning off a length of 5 metres by means of 
 a paper diaphragm, from a gun with a bore 4 cm. in diameter 
 and 70 cm. deep. The gun is inclined at a slight angle, and 
 the shots are fired without any stemming. There is a 
 statutory obligation for owners of fiery mines to use only 
 " safe explosives," but it rests with the owner to decide what 
 explosive is safe. Several private galleries also exist, 
 notably the one at Neubabelsberg. 
 
 The Austrian gallery is 293 metres long, and is part of 
 an abandoned mine. The shots are fired suspended in the 
 mine, and not from a gun, thus representing more or less 
 the conditions of an explosive exploding accidentally before 
 being placed in the shot hole. 
 
 The Belgian gallery at Frameries, near Mons, is similar 
 to the German gallery described above, but is 85 metres 
 long. The shots are fired unstemmed from a gun with a 
 bore 5*5 cm. in diameter and 46 cm. deep, the gun being 
 inclined at an angle. The explosive gas used is air containing 
 8 per cent, of fire damp, the mixture being warmed to 
 25 C. The power of the explosive is determined by com- 
 parison with Dynamite No. i in the Trauzl lead block, and 
 
122 EXPLOSIVES 
 
 in order to pass the test ten shots of an amount equivalent 
 to 175 grams of Dynamite must fail to fire the gas mixture, 
 and also fail to fire coal dust. The largest charge that satis- 
 fies these conditions is the " charge limite " or the maximum 
 amount of that explosive that may be used in any one blast. 
 
 The French galleries are at lyievin, one being 15 metres 
 long and 2 metres in area, and the other 300 metres long and 
 2 '8 metres in area, both being of circular section and supplied 
 with natural gas. The French regulations, however, are 
 not based on experiment, but rather on theoretical considera- 
 tions. For use in coal mines an explosive must on detonation 
 yield no combustible products such as carbon monoxide, 
 and for use in rock (explosif roche) its calculated temperature 
 must not exceed 1900 C., or for use in coal (explosif couche) 
 1500 C. These calculated temperatures are based on the 
 heat of combustion of the constituents and on the specific 
 heat of the products of combustion, and further details will 
 be found in Section VIII. 
 
 The United States gallery is situated at Pittsburg, It is 
 100 ft. long by 6 ft. 4 in. in diameter, and is constructed of 
 boiler plate, and closed at one end by concrete. Safet} 7 doors 
 are placed along the top to prevent undue pressure being 
 developed. Shelves are placed along the sides of the 
 gallery to hold coal dust, this dust being obtained from 
 bituminous coal ground until it passes a loo-mesh sieve. 
 
 The shots are fired unstemmed from a gun 24 in. in 
 diameter and 36 in. long, with a bore hole 2 J in. in diameter 
 and 21 J in. deep. Natural gas (roughly equal parts of 
 methane and ethane) is used, and the gas-air mixture is 
 warmed to 77 F. Power is determined in the ballistic 
 pendulum (see Section VIII.) and is compared with American 
 40 per cent. Straight Dynamite of the composition 
 
 N.G ....... 40 
 
 NaNO 3 ...... 44 
 
 W.M ....... 15 
 
 ...... i 
 
 In order to pass the test and be placed on the list of 
 
SAFETY COAL MINE EXPLOSIVES 123 
 
 " Permissible Explosives/' an explosive must fulfil the 
 following conditions : 
 
 1. Ten shots of a weight equivalent to | Ib. of the 
 standard 40 per cent. Dynamite fired into 8 per cent, of gas 
 must cause no explosion. 
 
 2. Ten shots of the same weight fired into 4 per cent, of 
 gas with the addition of 20 Ibs. of coal dust must cause no 
 explosion. 
 
 3. Ten shots of the same weight fired into 40 Ibs. of coal 
 dust must cause no explosion. 
 
 The limit-charge is determined by firing amounts in- 
 creasing by 25 grams into 4 per cent, of gas and 20 Ibs. of 
 coal dust until the maximum amount is found of which 
 10 shots can be fired without causing an explosion. The 
 composition of explosive is not published. 
 
 The first British gallery was built at Woolwich, and was 
 only 27 ft. 6 in. long by 2 ft. 6 in. diameter. The explosives 
 were fired from a gun with a bore hole 30 in. deep and if in. 
 diameter, and were stemmed with a definite weight of dry 
 clay. The explosive mixture used was air containing 15 per 
 cent, of coal gas. This gallery has been abandoned since 
 1912, in which year the Rotherham gallery came into use. 
 This is 50 ft. long by 5 ft. in diameter, and is constructed 
 of J in. mild steel plate. The explosion chamber is 18 ft. 
 long, and is separated from the rest of the gallery by a paper 
 diaphragm. The outer end is closed by a |-in. steel plate, a 
 hole being provided for inserting the gun and arrangements 
 made for a gas-tight joint. The explosion chamber has 
 three windows made of f-in. plate glass, each being 6 in. 
 square. There are nine pressure release valves on the top. 
 
 The gas is measured in a gas holder, and then made to 
 circulate with the air in the explosion chamber by means of 
 fans, complete mixing being brought about in 3 minutes. 
 The mixture used contains 13*4 per cent, of gas. 
 
 The gun is of steel (wire construction), with a bore hole 
 55 mm. in diameter and 120 cm. deep. 
 
 The following are the conditions regulating the test as 
 abstracted from A.R. 1912 : 
 
124 EXPLOSIVES 
 
 The explosive must be on the L,ist of Authorized Ex- 
 plosives. The Secretary of State may at any time cause 
 any explosive on the Permitted Ijst to be formally retested. 
 Notice of any such formal retest will be sent to the manu- 
 facturer of the explosive. 
 
 For the test the following weights and sizes of cartridges 
 must be supplied : 
 
 33 Ibs. if" x 8 oz. 
 10 Ibs. if" x 4 oz. 
 
 5 Ibs. if" x 2 oz. 
 
 2 Ibs. if" x 4 oz. 
 
 The Secretary of State reserves to himself the right of 
 storing all explosives submitted for the Official Test for at 
 least 30 days prior to the test. 
 
 The fees for testing an explosive are : 
 
 Testing a new explosive . . . . . . 50 
 
 Testing an altered explosive . . . . . . 30 
 
 Bach experimental shot . . . . . . i 
 
 These experimental shots have no official significance, but 
 are for the benefit of manufacturers in order to enable them 
 to form some idea as to whether an explosive is likely to pass 
 or not before paying the somewhat heavy fee for the Official 
 Test. 
 
 The Official Test is carried out as follows (official descrip- 
 tion) : 
 
 " Shots will be fired into a mixture of gas and air until 
 the largest charge which can be fired without igniting it is 
 found. Further shots will then be fired, beginning with this 
 charge and, in the event of an ignition, reducing the charge 
 until five shots of the same weight have been fired without 
 igniting the mixture. Shots will then be fired with the 
 charge so determined into coal dust, and the same procedure 
 adopted until 5 shots have been fired without igniting the 
 coal dust. The lower of the charges thus determined will 
 be known as the ' maximum charge/ In making alterations 
 
SAFETY COAL MINE EXPLOSIVES 125 
 
 to the weight of the charges, the increment or decrement 
 of charge will not be less than two ounces." 
 
 " In loading the gun the charge will be pushed to the 
 bottom of the bore (a clay plug having been previously 
 inserted to protect the crown of the bore), and will have no 
 tamping. The coal dust will be ground to such a degree of 
 fineness that not less than 90 per cent, will pass through a 
 sieve of 150 meshes to the linear inch." 
 
 " In addition to the foregoing shots, other shots will be 
 fired at the ballistic pendulum, and the swings registered on 
 the sliding scale provided for the purpose will be recorded. 
 The mean swing thus obtained will be published in com- 
 parison with that given by a charge of Gelignite containing 
 60 per cent, of nitroglycerine." 
 
 " Every shot will be fired electrically, and in the case of 
 high explosives a detonator of the size recommended by the 
 manufacturer or the person submitting the explosive will, 
 subject to the approval of the Home Office, be used." 
 
 " Each shot will be fired in the case, wrapper or covering 
 in which the explosive is proposed to be employed in actual 
 use." 
 
 " An explosive will be considered to have passed the test 
 if- 
 
 " (i) The ' maximum charge ' as above determined, is not 
 
 less than eight ounces. 
 
 " (2) If in the shots at the pendulum no appreciable 
 amount of the charge has been left unexploded. 
 " (3) If, in the opinion of the officer in charge of the 
 testing, the explosive has exploded in a satisfactory 
 manner when fired untamped at the gallery." 
 " The heaviest charge which may be fired from the gun 
 is 2} Ibs." 
 
 The following are extracts from the chief conditions 
 governing the packing and use of Permitted Explosives (Coal 
 Mines Act, Order in Council, Sept. ist, 1913) : 
 
 " No drill shall be used for boring a shot hole unless it 
 allows at least a clearance of J in. over the diameter of the 
 cartridge which is intended to be used in the shot hole." 
 
126 EXPLOSIVES 
 
 " Every charge shall . . . have sufficient stemming, and 
 each such charge shall consist of a cartridge or cartridges of 
 not more than one description of explosive." 
 
 " In all coal mines in which inflammable gas has been 
 found within the previous three months in such quantity as 
 to be indicative of danger, no explosive, other than a 
 Permitted Explosive . . . shall be used." 
 
 " In all coal mines which are not naturally wet throughout 
 no explosive, other than a Permitted Explosive . . . shall 
 be used ... in any road or any dry and dusty part of the 
 mine." 
 
 The following regulations must be followed as regards 
 packing and marking, and are in addition to those made 
 under the Explosives Act, 1875 : 
 
 Every outer package must bear the words " As defined in 
 the lyist of Permitted Explosives." 
 
 Each inner package must bear the words " Permitted 
 Explosive, to be used only with not less than No. 
 detonator," the number of the detonator being that which is 
 given in the Permitted I4st. It must also be marked with 
 the name of the explosive, the name of the manufacturer, 
 the place and date of manufacture, and the nature and 
 proportion of the ingredients as set forth in the Permitted 
 lyist. 
 
 Each cartridge must be stamped with a P set in a crown, 
 and must bear the words " Not more than ounces in any 
 one shot hole," the number of ounces being the maximum 
 charge as determined by the Official Test. 
 
 In the Permitted I/ist each explosive is denned as con- 
 sisting of certain ingredients, a maximum and minimum 
 figure being given for each to allow for manufacturing error. 
 This allowance, which is fixed by the manufacturer with 
 the approval of the Home Office, is frequently absurdly high. 
 For example, Super-excellite No. 2 is defined as containing 
 not more than 6 or less than 4 parts by weight of nitro- 
 glycerine. In making up a 500-lb. batch with the mean 
 value, 5 parts, 25 Ibs. of nitroglycerine would be required, but 
 an error of 5 Ibs. in either direction might be made without 
 
SAFETY COAL MINE EXPLOSIVES 127 
 
 departing from the definition. Needless to say an error of 
 5 in 25 is absurd. A liberal allowance with a hygroscopic 
 substance like ammonium nitrate is more sensible, but even 
 here the allowance is decidedly high. These high allow- 
 ances for error mean that a manufacturer could make an 
 explosive with a number of ingredients and submit a sample 
 to the Official Test in which the inert matters were kept at 
 their maximum and the active ingredients at a minimum. 
 After having passed the test he could then reverse the process 
 and sell an explosive in which the inert material was at a 
 minimum, and the active ingredients at a maximum, although 
 this actual mixture might not have passed the test if sub- 
 mitted. 
 
 The Permitted lyist also states the name of the manu- 
 facturer, and the situation of the factory in which the 
 explosive must be made, the smallest detonator which may 
 be used to fire the explosive and the greatest weight that 
 may be used in any one shot hole. It states the nature of 
 the wrapper, e.g. parchment paper, tin-lead alloy cases, etc., 
 and in the case of waterproofed cartridges states the nature 
 of the waterproofing material, e.g. paraffin wax, carnauba 
 wax, wax and resin, etc. It does not, however, set any 
 limit to the relative weight of the wrapper, although this is 
 considerable, especially in small cartridges, and when of a 
 combustible nature forms a part of the explosive. However, 
 the weight of the wrapper would be difficult to fix, as it 
 varies so much with the different sizes and, possibly, is not 
 of such importance as it would appear to be. For example, 
 Ammonite No. i and Ammonite No. 5 have the same com- 
 position, viz. 
 
 AmNO 3 73-77 
 
 T.N.N 4-6 
 
 NaCl 19-5-21-5 
 
 H 2 O o-i 
 
 but No. 5 is made up in waxed paper cartridges, whereas 
 No. i is made up in cases " of lead and tin alloy thoroughly 
 waterproofed with pure paraffin wax." The former gives 
 
128 EXPLOSIVES 
 
 a swing of 2*41 in. with the ballistic pendulum and has a 
 maximum charge of 26 oz., whereas the latter gives a 
 swing of 2*42 in., and has a maximum charge of 24 oz. 
 These figures are very close, but it must be borne in 
 mind that both are stated to be waxed, and that Ammonite 
 contains a very large excess of oxygen over and above that 
 required for the complete combustion of the trinitronaphtha- 
 line present. The case might be quite different with those 
 explosives which contain only just sufficient oxygen for 
 complete combustion, as the waxed wrapper would then 
 cause the production of large quantities of carbon monoxide. 
 In order to examine the influence of the wrapper two 
 series of experiments were carried out in the Belgian galleries. 
 In the first series Grisounite roche, an explosive containing a 
 considerable excess of oxygen and having the composition 
 
 AmNO 3 . . . . . . 91*5 
 
 D.N.T. .. 8-5 
 
 was used, and the combustible gas in the products of com- 
 bustion estimated. The results obtained were striking 
 
 Per cent. 
 Wrapper. combustible gas. 
 
 None . . . . . . . . . . . . 2*4 
 
 Asbestos paper . . . . . . . . 4*0 
 
 Paraffined paper . . . . . . 20*0 
 
 Aluminium or tinfoil . . . . . . 2*0 
 
 Paraffined paper plus 20 grams coal dust . . 37*5 
 
 Tin foil plus 20 grams coal dust . . . . 55*6 
 
 The last figure is rather extraordinary and seems difficult of 
 explanation. 
 
 In the second series of experiments various Belgian coal 
 mine explosives were fired in the gallery with different 
 wrappers, and the charge limite determined. In all cases the 
 use of paraffined paper in place of unparaffined paper 
 lowered the charge limite to a very marked extent, in some 
 cases by as much as 85 per cent., both when fired into gas 
 and when fired into coal dust. Metal foil also reduced the 
 charge limite but to a lesser extent, this reduction being 
 
SAFETY COAL MINE EXPLOSIVES 129 
 
 probably due partly to the great heat of combustion of the 
 metal. The substitution of asbestos paper for ordinary 
 paper, on the other hand, was found to raise the charge limite 
 by as much as 50 per cent. From this it is obvious that the 
 effect of the wrapper is very great, but no data are available 
 as to the influence of wrappers on different sizes of cartridges, 
 nor do any experiments seem to have been carried out in 
 this country. 
 
 In gallery tests the diameter and length of the bore hole 
 of the gun used affects the test to a marked extent, and 
 experiments have been carried out in Germany on these 
 lines. Two guns were used, one having a bore 55 mm. in 
 diameter and 57*5 cm. long, and one having a bore 40 mm. 
 in diameter and 70 cm. long. It was found that when 
 fired from the 55 mm. gun cartridges of 35 mm. diameter 
 gave decidedly higher maximum charges when fired into gas 
 than cartridges of 55 mm. diameter, whereas with coal dust 
 there was but little difference. On the other hand, 35 mm. 
 cartridges fired from a 40 mm. gun gave slightly higher charges 
 both in gas and in coal dust than did 40 mm. cartridges. 
 
 The length of the bore hole has also a considerable 
 influence, the longer the hole the bigger the maximum charge 
 obtained, but this is probably due to the increased cooling 
 surface of the metal. The influence of the magnitude of the 
 sectional area of the gallery has also been studied, and a 
 decreasing area is accompanied by a decreasing charge 
 limite, but results are very irregular. In some cases the 
 reduction is greatest when the explosive is fired into gas, and 
 in others the reduction is greater when coal dust is used. 
 
 No gallery test can be said to represent the conditions 
 actually attained in mining practice, but they all err on the 
 safe side by providing for conditions more dangerous than are 
 likely to be met with. Tamping has a great influence, and 
 the absence of tamping makes the gallery tests much more 
 severe, whereas in blasting, of course, shots are never fired 
 without stemming. 
 
 As regards the British test, this differs from the Belgian 
 and American tests by not specifying any temperature for 
 T. 
 
130 EXPLOSIVES 
 
 the gas in the explosion chamber, although workings are 
 frequently decidedly warm. Another point which seems to 
 be completely overlooked is barometric pressure. Some 
 workings are several thousand feet deep, and as the baro- 
 metric height increases by about -f 6 in. for every hundred 
 feet descended, the increased pressure in these workings is 
 considerable. Surface variations of barometer in this 
 country do not, as a rule, exceed i in., corresponding to 
 a depth of 1000 ft., but pending properly constituted experi- 
 ments it would be an advantage if the barometer reading 
 and temperature of the gas at the time of the test was stated 
 in the Permitted Ivist. Owing to the slight variations of 
 barometric pressure experienced the information might not 
 be of great value, but the trouble would be so slight that it 
 would be worth doing. As will be seen from the above 
 remarks, a vast amount of experimental work should be 
 carried out on the use of explosives in the presence of in- 
 flammable gas mixtures and coal dust. So far no work at all 
 seems to have been done in this country, except the official 
 testing of explosives for manufacturers. Owing to the 
 expense it is hardly work that a private individual, or even 
 a company, would care to take up, and from the national 
 importance of the subject it is decidedly one that should be 
 taken in hand by the Government. The Rotherham station 
 has now been in use for six years, but so far there seems to 
 have been no attempt made to carry out any research. The 
 subjects that particularly require investigating are : (i) the 
 influence of the wrapper; (2) the influence of barometric 
 pressure ; (3) the relative efficiency of the various " coolers " ; 
 (4) temperature of explosion; (5) duration of flame; (6) 
 velocity of detonation ; and (7) the diameter of the cartridges. 
 British Permitted Explosives. The number of explo- 
 sives on the British I^ist of Permitted Explosives is now (1919) 
 77. Of these all the non-hygroscopic explosives are put up 
 in cartridges of parchment paper, whereas with one or two 
 exceptions the hygroscopic explosives are put up in paper 
 cases made thoroughly waterproof with a wax such as 
 paraffin, carnauba or ceresin wax, or with a mixture of wax 
 
SAFETY COAL MINE EXPLOSIVES 131 
 
 and resin. Of the exceptions Stanford Powder, Ammonite 
 No. i and Ammonite No. 4 are put up in cases made of lead 
 and tin alloy, thoroughly waterproofed with wax ; and 
 Abelite No. 4 is put up in a waxed paper case " with or 
 without an additional covering of tin foil." A German ex- 
 plosive, Tutol No. 2, which was on the list at the outbreak of 
 the war, was put up in a non- waterproofed wrapper of parch- 
 ment paper and an outer wrapper of waterproofed paper, 
 this outer wrapper being removed before charging the shot 
 hole. This was an obvious attempt to get over the influence 
 of the wrapper as far as possible, and although the explosive 
 is no longer on the Permitted I^ist it is worth giving its 
 composition 
 
 N.G 24-26 
 
 NaNO 3 28-30 
 
 NaCl 8-5-10-5 
 
 W.M 31-34 
 
 NaHC0 3 o--5 
 
 H 2 2-5-5 
 
 It gave a swing at the ballistic pendulum of 2'ii in., as 
 compared with 3-27 in. given by an equal weight of 
 Gelignite containing 60 per cent, of nitroglycerine, and the 
 maximum charge was 22 oz. 
 
 It is difficult to classify the explosives on the list, but, 
 roughly, they fall into three groups, viz. (i) those containing 
 no nitroglycerine, but consisting of a nitroaromatic hydro- 
 carbon in conjunction with ammonium nitrate with or 
 without sodium or potassium nitrate ; (2) those containing 
 nitroglycerine and combustible matter in conjunction with 
 a nitrate ; (3) those containing potassium perchlorate. 
 
 It is noticeable that the only explosives containing barium 
 nitrate are those rich in nitroglycerine (20-30 per cent.) and 
 containing no nitroaromatic compound, and that all the 
 perchlorate explosives are also rich in nitroglycerine (20-40 
 per cent.) except Sunderite, which contains only 8-10 parts. 
 
 Of the " coolers," the chlorides of sodium, potassium and 
 ammonium are all used, of which the potassium salt seems to 
 be the most effective. Ammonium chloride tends to spoil 
 
132 
 
 EXPLOSIVES 
 
 detonation, and in any case can only be used in conjunction 
 with sodium or potassium nitrate, as a fixed base must be 
 provided with which the chlorine liberated can combine. 
 Ammonium oxalate is also used as a cooler, but its use up 
 to the present is confined to explosives containing nitro- 
 glycerine. It is present in large quantity, 25-40 per cent., 
 in all the perchlorate mixtures except Samsonite No. 2. 
 
 The most powerful explosive on the list is Victor Powder, 
 containing about 9 per cent, of nitroglycerine and giving a 
 swing of 2*96 in., the next most powerful being Nationalite 
 No. i, containing as explosive ingredients only T.N.T. and 
 ammonium nitrate, and giving a swing of 2*91 in. 
 
 No attempt will be made to enumerate all the explosives 
 on the list, but the following tables give some of the chief 
 ones arranged for purposes of comparison. In all cases, the 
 " swing " is that given at the ballistic pendulum by 4 oz., 
 and is to be compared with the swing of 3*27 in. given by 
 the same weight of Gelignite containing 60 per cent, of nitro- 
 glycerine. 
 
 The mean value of the maximum and minimum parts by 
 weight as set forth in the L,ist of Permitted Explosives is 
 given in all cases. 
 
 EXPLOSIVES CONTAINING NO NG. 
 
 
 
 
 
 
 
 
 
 
 
 
 gu 
 
 rt "> 
 
 Explosive. 
 
 H 
 
 
 
 o 
 
 
 0* 
 
 n 
 
 O 
 
 . 
 
 
 
 3 
 
 
 t'n 
 C 
 
 u C 
 J O 
 
 
 /H 
 
 & 
 
 e 
 
 fc 
 
 rt 
 
 d 
 
 rt 
 
 a 
 
 e* 
 
 
 S3 
 
 
 H 
 
 Q 
 
 
 
 fc 
 
 
 fc 
 
 
 K 
 
 W 
 
 s 
 
 Bellite No. 2 
 
 _ 
 
 12 
 
 61 
 
 _ 
 
 _ 
 
 
 
 27 
 
 . 
 
 '35 
 
 2-42 
 
 32* 
 
 Bellite No. 4 
 
 
 
 13 
 
 68-5 
 
 
 
 
 
 
 
 18 
 
 
 
 7.5 
 
 272 
 
 12 
 
 Abelite No. i 
 
 67 
 
 7 
 
 68 
 
 
 
 - 
 
 
 
 17*5 
 
 
 
 '5 
 
 2-85 
 
 14 
 
 Nationalite No. i 
 
 1.5 
 
 
 
 66 
 
 
 
 
 
 
 
 I9'5 
 
 
 
 '5 
 
 2-92 
 
 12 
 
 Bellite No. i f 
 
 15 
 
 
 
 63-5 
 
 
 
 
 
 
 
 16-5 
 
 
 
 
 
 274 
 
 20 
 
 Nationalite No. 2 
 
 15 
 
 
 
 63-5 
 
 
 
 
 
 21 
 
 
 
 . 
 
 5 
 
 2-63 
 
 20 
 
 Roburite No. 4 
 
 16-5 
 
 
 
 60 '5 
 
 
 
 - 
 
 
 
 22*5 
 
 
 
 75 
 
 2-86 
 
 18 
 
 Kentite 
 
 15 
 
 
 
 34 
 
 33*5 
 
 
 
 
 
 
 
 I 7 
 
 i 
 
 2*64 
 
 18 
 
 Anchorite.. . . ' 12 
 
 
 
 34 
 
 
 
 33 
 
 
 
 
 
 20 
 
 75 
 
 273 
 
 14 
 
 Expedite . . . . 12 
 
 
 
 34*5 
 
 33 
 
 
 
 
 
 
 
 2O 
 
 75 
 
 2-62 
 
 32 
 
 Denaby Powder ..13 
 
 
 
 34 
 
 33*5 
 
 
 
 
 
 
 
 *9'5 
 
 75 
 
 274 
 
 18 
 
 Super-Curtisite . . 10 
 
 
 
 
 29'5 
 
 
 
 
 
 
 
 22 
 
 i 
 
 271 
 
 16 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 * This was the largest charge that could be loaded into the gun. 
 f Contains also 3*5-5 '5 parts of starch. 
 
COAL MINE EXPLOSIVES 133 
 
 In the preceding table the following comparisons are in- 
 teresting. Bellite No. 4 and Abelite No. i are almost identi- 
 cal in composition, except that in the latter half the D.N.B. 
 has been replaced by an equal weight of T.N.T. This has 
 increased the power and at the same time raised the maxi- 
 mum charge by 2 oz. In Nationalite No. i the substitution 
 has been taken further, with the result that still greater 
 power is obtained, although the maximum charge has fallen 
 back to 12 oz. Bellite No. i differs only from Nationalite 
 No. i in containing less salt and rather less ammonium 
 nitrate which, surprisingly enough, has caused a falling off 
 in power and an increase in the maximum charge. This may 
 be due to influence of wrapper, or more likely to a different 
 method of incorporating the ingredients. Anchorite and 
 Expedite are very similar in composition, although the 
 maximum charges show a big difference. 
 
 The following permitted explosives contain no nitro- 
 glycerine, and all contain a very large excess of oxygen over 
 and above that required for the complete combination of 
 the oxidizable ingredients : 
 EXPLOSIVES CONTAINING NO N.G. BUT A LARGE EXCESS OF OXYGEN. 
 
 Explosive. 
 
 H 
 
 55 
 
 55* 
 Jzj 
 
 jzs 
 
 fc 
 
 i 
 
 a 
 
 o 
 
 i 
 
 
 
 
 ^ 
 
 . 
 
 "S 
 
 !| 
 1 
 
 
 H 
 
 Q 
 
 H 
 
 
 fc 
 
 H 
 
 & 
 
 
 
 < 
 
 K 
 
 w 
 
 ^ 
 
 Dreadnaught 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Powder 
 
 4 
 
 
 
 
 
 75 
 
 I5-5 
 
 
 
 
 
 
 
 5 
 
 '5 
 
 2-05 
 
 32 
 
 Westfalite No. 3 
 
 5 
 
 . 
 
 
 
 59'5 
 
 
 14 
 
 
 
 
 
 21 
 
 '5 
 
 2'55 
 
 12 
 
 Ammonite 
 
 
 5*5 
 
 
 
 73 
 
 . 
 
 
 21 
 
 
 
 
 
 '5 
 
 2-44 
 
 18 
 
 Ammonite No. 4 
 
 
 
 4 
 
 
 
 66 
 
 10 
 
 
 
 
 
 20 
 
 
 
 '5 
 
 I '76 
 
 30 
 
 Ammonite No. 5 
 
 
 
 
 5 
 
 75 
 
 
 
 
 
 20-5 
 
 
 
 
 
 '5 
 
 2*41 
 
 26 
 
 Ammonite No. i 
 
 
 
 
 
 5 
 
 75 
 
 
 
 -* 
 
 20-5 
 
 " 
 
 *~~ 
 
 '5 
 
 2*42 
 
 24 
 
 In the above, Dreadnaught Powder is interesting as having 
 a large maximum charge, although it contains very little 
 cooler. Also the difference in the maximum charges of 
 Ammonite and Ammonite No. 5 is bigger than one would 
 expect from the slight difference in composition. The only 
 difference between the composition of Ammonite No. i and 
 Ammonite No. 5 is that the latter is put up in waxed paper 
 and the former in metal foil cases. 
 
134 
 
 EXPLOSIVES 
 
 EXPLOSIVES POOR IN N.G. 
 
 Explosive. 
 
 o* 
 fc 
 
 i 
 
 n 
 
 | 
 
 i 
 
 
 f 
 
 4 
 
 1 
 
 i 
 
 H 
 
 O 
 
 5 
 < 
 
 O^ 
 
 sT 
 
 t 
 
 1 
 
 & . 
 
 I- *~* 
 JO 
 
 Jl 
 
 Super-Excellite 
 
 4-2 
 
 3 
 
 75'2 
 
 7-2 
 
 _ 
 
 _ 
 
 _ 
 
 _ 
 
 10 
 
 75 
 
 274 
 
 10 
 
 Super-Excellite 
 No. 2 . . 
 
 5 
 
 
 
 50 
 
 20 
 
 __ 
 
 ^ 
 
 __ 
 
 5 
 
 15 
 
 75 
 
 272 
 
 14 
 
 A i Monobel . . 
 
 10 
 
 
 
 60 
 
 
 
 
 
 
 
 20 
 
 
 
 i 
 
 278 
 
 28 
 
 A 2 Monobel * . . 
 
 IO 
 
 9 
 
 59 
 
 
 
 
 
 
 
 20 
 
 . 
 
 
 
 i 
 
 2 '44 
 
 22 
 
 Thames Powder 
 
 
 
 
 
 
 
 
 
 
 
 
 
 No. 2 . . 
 
 10 
 
 9 
 
 58-5 
 
 
 
 . 
 
 21 
 
 
 
 
 
 
 
 i 
 
 2 '59 
 
 22 
 
 Viking Powder* 
 
 
 
 
 
 
 
 
 
 
 
 
 
 No. i . . 
 
 10 
 
 9 
 
 59 
 
 
 
 
 
 19*5 
 
 
 
 . 
 
 
 
 i 
 
 2*44 
 
 26 
 
 Viking Powder * 
 
 
 
 
 
 
 
 
 
 
 
 
 
 No. 2 . . 
 
 8'5 
 
 8 
 
 67 
 
 
 
 
 
 15 
 
 
 
 . 
 
 
 
 
 2'59 
 
 18 
 
 Rex Powder 
 
 12 
 
 7'7 
 
 59'5 
 
 
 
 
 
 I9'5 
 
 
 
 
 
 
 
 "2 
 
 2'6l 
 
 20 
 
 Stomonal No. i 
 
 10 
 
 
 56 
 
 
 
 6 
 
 I9'5 
 
 
 
 
 
 
 
 
 2-68 
 
 20 
 
 Stomonal No. 2 
 
 10 
 
 6 
 
 61 
 
 
 
 
 
 17 
 
 . 
 
 . 
 
 6 
 
 
 2'57 
 
 3 
 
 Monobel No. i . . 
 
 8'5 
 
 8 
 
 68 
 
 
 
 . . 
 
 15 
 
 . 
 
 
 
 
 
 
 2'8l 
 
 10 
 
 Victor Powder . . 
 
 8-5 
 
 8 
 
 68 
 
 
 
 
 
 
 15 
 
 
 
 
 
 
 2-96 
 
 18 
 
 Victor Powder 
 
 
 
 
 
 
 
 
 
 
 
 
 
 No. 2 f 
 
 8'5 
 
 8 
 
 66-5 
 
 
 
 . 
 
 
 
 15 
 
 
 
 
 
 I 
 
 2-63 
 
 16 
 
 Du Font's Per- 
 
 
 
 
 
 
 
 
 
 
 
 
 
 missible No. i 
 
 9*5 
 
 7*5 
 
 67'5 
 
 
 
 
 
 15 
 
 
 
 
 
 
 
 "75 
 
 2-82 
 
 18 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 * Contains in addition '5-1*5 MgCO 3 . f Contains in addition 0-2 MgCO 3 . 
 
 Of the powders in the above list Ai Monobel and Stomonal 
 No. i both contain a large excess of oxygen, this being reme- 
 died in the case of A2 Monobel by the addition of wood meal. 
 
 A2 Monobel is almost identical with Viking Powder No. i, 
 except that in the latter sodium chloride has been substituted 
 for potassium chloride, the result being an increased maximum 
 charge with the same power contrary to what would be ex- 
 pected (cf. Monobel No. i and Victor Powder). On the 
 other hand, Thames Powder No. 2 is almost identical with 
 Viking Powder No. i, but has a smaller maximum charge, 
 although it is more powerful. As these explosives are made 
 by different firms the variation may be due to different 
 mixing or to a different amount of wax on the wrapper. 
 
 Victor Powder and Victor Powder No. 2 are very 
 similar, except for an optional 0-2 per cent, of magnesium 
 carbonate in the latter, and the difference in power is quite 
 remarkable. The official definition gives in each case nitro- 
 glycerine 7'5-9'5, potassium chloride 14-16, and wood meal 
 
SAFETY COAL MINE EXPLOSIVES 135 
 
 7-9. For Victor Powder the ammonium nitrate is given as 
 66-5-69-5, and for Victor Powder No. 2 as 65-68 with 
 magnesium carbonate 0-2. Consequently without departing 
 from the definition the two explosives could be made up to 
 have the same composition, and this serves as a good example 
 of the excessive allowance for manufacturing error permitted 
 in the definition (see p. 126). Du Font's Permissible No. i is 
 the only American made explosive on the British Permitted 
 L,ist at present. It is very similar to Viking Powder No. 2. 
 Dynobel No. 3 and No. 4 have the following composition, 
 and represent an intermediate stage between the foregoing 
 explosives poor in nitroglycerine and the explosives rich in 
 nitroglycerine :- Dynobel Dynobel 
 
 No. 3. No. 4. 
 
 N.G. . . . . . . . . 14-16 14-16 
 
 C.C '25-75 '25-75 
 
 D.N.B. ) 
 
 D.N.T. 2-5-5 2-4 
 
 T.N.T. j 
 
 AmNO 3 51-54 44-47 
 
 W.M 4-6 4-6 
 
 NaCl 24-26 28-31 
 
 MgCO 3 o-i o-i 
 
 H 2 O . . . . . . . . 0-2 0-2 
 
 Swing 2-50 2-35 
 
 Max. charge . . . . 18 oz. 30 oz. 
 
 Dynobel No. 2 is similar, but contains more nitroglycerine, 
 
 18-5-20-5 parts. 
 
 EXPLOSIVES RICH IN N.G. 
 
 Explosive. 
 
 
 
 o 
 
 . 
 
 1 
 
 cf 
 
 ~c? 
 
 o" 
 
 o" 
 
 ^ 
 
 X 
 
 O 
 
 a 
 
 O 
 
 si 
 '$ 
 
 If 
 
 
 S5 
 
 o 
 
 ^ 
 
 en 
 
 a 
 
 ^ 
 
 M 
 
 X 
 
 
 K 
 
 W 
 
 s 
 
 Britonite No. 2 . 
 
 24 
 
 _ 
 
 35 
 
 _ 
 
 . . 
 
 
 
 30-5 
 
 _, 
 
 8 
 
 3-2 
 
 2-26 
 
 24 
 
 Pitite No. 2 
 
 24 
 
 . 
 
 34*5 
 
 
 
 
 
 
 
 29'5 
 
 
 
 8 
 
 37 
 
 2-15 
 
 32 
 
 Super-Kolax 
 
 25-5 
 
 
 
 27 
 
 7 
 
 
 
 
 25*5 
 
 
 
 7 
 
 3 
 
 2*10 
 
 3 
 
 Super- Kolax No. 
 
 28-5 
 
 I 
 
 28 
 
 8-5 
 
 5 
 
 
 
 i6'5 
 
 
 
 9'5 
 
 3'5 
 
 2'2I 
 
 32* 
 
 Cambrite . . 
 
 23 
 
 
 
 33*5 
 
 
 
 3'7 
 
 
 
 27'5 
 
 
 
 8 
 
 4*7 
 
 1*98 
 
 3 
 
 Kynarkite 
 
 25 
 
 
 
 35 
 
 
 
 3 
 
 
 
 28 
 
 
 
 5 
 
 3'7 
 
 2'2I 
 
 20 
 
 Britonite No. 3 . 
 
 24'5 
 
 
 
 
 ~ 
 
 
 _ 
 
 28 
 
 12 
 
 _ 
 
 3 
 
 2-59 
 
 22 
 
 * This was the greatest weight that could be loaded into the gun. 
 
136 EXPLOSIVES 
 
 It should be noticed that Britonite No. 2 and Pitite No, 2 
 are very similar, and the two explosives could be made up to 
 have the same composition without departing from their 
 official definitions, although the maximum charge differs 
 by 8 oz. 
 
 It will further be observed that in all these explosives a 
 large quantity of wood meal is used to absorb the nitro- 
 glycerine, and that, except in the case of Britonite No. 3, 
 deliquescent salts are not used. This is on account of the 
 danger of water being taken up and displacing the nitro- 
 glycerine. 
 
 A comparison of Duxite and Arkite No. 2 is very in- 
 structive in showing the great difference in maximum charge 
 that can be brought about by a slight difference in composi- 
 tion. Duxite is a German-made explosive that was placed 
 on the British Permitted I/ist in 1914, although it has since 
 been removed. Arkite is made by Kynoch-Arklow, I/td., 
 and was also placed on the list in 1914, and is still there. The 
 official definitions of these explosives are 
 
 Duxite. Arkite No. 2. 
 
 N.G 31-33 31-33 
 
 C.C 75-1*5 '5-1-5 
 
 NaNO 3 . . . . . . . . 27-29 
 
 KNO 3 .. 26-28 
 
 W.M 8-10 8-10 
 
 AmOx. . . . . . . . . 28-31 29-31 
 
 H 2 O 0-2-5 0-2 
 
 Swing . . . . . . . . 2-45 2*41 
 
 Max. Charge . . . . . . 12 oz. 40 oz. * 
 
 As will be seen, the two explosives are almost identical, 
 except that Duxite contains sodium nitrate in place of 
 potassium nitrate. The enormous difference in the maximum 
 charges is probably due to the wrapper, Arkite No. 2 being 
 put up in parchment paper and Duxite in paper water- 
 proofed with paraffin wax. 
 
 The only Permitted Explosive which is a true jelly is 
 Super- Rippite. It is officially defined as follows : 
 
 * This is the greatest charge which may be loaded into the gun. 
 
SAFETY COAL MINE EXPLOSIVES 137 
 
 N.G 
 
 C.C 
 
 KNO 3 
 
 Borax (dried at 100' 
 
 KC1 
 
 H 2 O (total) 
 
 Swing 
 
 Max. charge 
 
 C. 
 
 51-53 
 2-4 
 
 7-9 
 5-8 
 
 2'53 
 18 oz. 
 
 It is put up in non-waterproofed wrappers of parchment 
 paper. Samsonite No. 2 and Samsonite No. 3 are somewhat 
 similar, but the former contains 10-12 parts of potassium 
 perchlorate. 
 
 The following explosives containing potassium perchlorate 
 are on the Permitted L,ist : 
 
 EXPLOSIVES CONTAINING PERCHLORATE. 
 
 
 
 
 $ 
 
 P.H 
 
 
 
 
 
 
 
 ff 
 
 Explosive. 
 
 
 
 H^ 
 
 jd 
 
 
 f? 
 
 X 
 
 
 ai 
 
 38 
 
 
 o 
 
 o 
 
 *a 
 
 
 
 * 
 
 3 
 
 O 
 
 a 
 
 o 
 
 | 
 
 as. 
 
 
 
 
 o 
 
 H 
 
 C/l 
 
 & 
 
 
 
 < 
 
 K 
 
 W 
 
 s 
 
 Swale Powder 
 
 19 
 
 I 
 
 4 
 
 _ 
 
 9 
 
 37*5 
 
 28 
 
 I 
 
 2'50 
 
 20 
 
 Ajax Powder 
 
 22-5 
 
 '75 
 
 3 
 
 
 
 10-5 
 
 37*5 
 
 25 
 
 '75 
 
 2*69 
 
 12 
 
 Neonal . . 
 
 21 
 
 i 
 
 '2 
 
 
 
 15 
 
 37 
 
 25 
 
 i 
 
 2-56 
 
 16 
 
 Dynobel .. 
 
 32-5 
 
 '75 
 
 
 
 
 
 9'5 
 
 27 
 
 29*5 
 
 '75 
 
 2'6l 
 
 22 
 
 Herculite 
 
 33 
 
 i 
 
 
 
 
 
 9 
 
 27 
 
 29 
 
 i 
 
 2'72 
 
 16 
 
 Neonal No. i 
 
 40 
 
 2 
 
 ~ 
 
 ~ 
 
 4*5 
 
 H 
 
 39*5 
 
 '5 
 
 2'5I 
 
 3<> 
 
 Among these it is noticeable that Dynobel and Herculite 
 are almost identical in composition and could be made to 
 have the same composition without departing from the 
 official definitions. The difference of the maximum charges 
 is 6 oz., which may be accounted for by a different 
 method of mixing, as the explosives are made by different 
 firms, Dynobel being made by Nobel's Explosives Co., Ltd., 
 and Herculite by the British Explosives Syndicate. 
 
 Bobbinite is a non-detonating explosive of the gunpowder 
 type which has failed to pass the Rotherham test, but the 
 use of which is permitted under certain conditions until 
 December 3ist, 1919. There are two definitions, of which 
 the second is the most popular 
 
138 EXPLOSIVES 
 
 ist Definition. 2nd Definition. 
 KNO 3 62-65 63-66 
 
 c 17-19*5 18-5-20-5 
 
 s .. 1-5-2-5 1*5-2-5 
 
 Ammonium Sulphate > 
 
 Copper Sulphate 5 3 7 
 
 Paraffin Wax . . . . 7-9 
 
 Rice or Maize Starch . . 2-5-3-5 
 
 Moisture . . . . . . 0-2-5 "3 
 
 Density (not exceeding) . . 1-42 1*48 
 
 Each pellet must be coated with paraffin wax of a melting 
 point not less than 1 20 Fahr., and be contained in a wrapper 
 of brown paper. There is no limit to the charge which may 
 be used. 
 
 The conditions for its use are as follows : It may only be 
 used " for bringing down coal (whether by shots placed in 
 the coal or by shots placed in the stratum immediately above 
 or below the coal) and only in ... mines which are not 
 liable to blowers or sudden outbursts of firedamp, and in 
 which firedamp does not exist in the coal at a pressure which 
 makes the use of such explosives dangerous, and in which the 
 dust ... is either naturally so largely composed of in- 
 combustible matter as not to be dangerous or has been 
 rendered so by artificial means." 
 
 " The explosives shall only be used with an electric fuse 
 containing 5 grains of gunpowder or with other means 
 equally efficient in igniting the explosive, but not with a 
 detonator or electric detonator." 
 
 German Explosives. A considerable number of 
 " Wettersichere Sprengstoffe " are available for use in 
 German coal mines, of which the following give a fair idea 
 of the types used : 
 
 Neu Westfalit. Wetter-Fulmenit. 
 
 D.N.T. .. 10-9 T.N.T. .. 5*5 
 
 AmNO 3 . . 70-3 G.C. . . 4*0 
 
 Flour * .. 2-0 AmNO 3 .. 75*5 
 
 NaCl .. 16-8 C .. .. i'5 
 
 Max. charge 540 grams. Paraffin oil 2 '5 
 
 NaCl 10 -o 
 
SAFETY COAL MINE EXPLOSIVES 139 
 
 Dahmenit. 
 Naphthalene 
 AmNO 3 
 K 2 Cr 2 O 7 
 
 T.N.T. 
 AmNOg 
 KNOg . . 
 Flour .. 
 Nad .. 
 Max. Charge 
 
 Tremonite S. II. 
 Dinitroglycerol 
 
 C.C 
 
 Meal 
 
 T.N.T 
 
 AmNO 3 
 NaCl 
 
 Dorfit I. 
 
 Dorfit II. 
 
 6 
 
 15 
 
 61 
 
 65 
 
 5 
 
 5 
 
 4 
 
 4 
 
 20 
 
 15 
 
 532 grams. 
 
 300 grams. 
 
 33 
 i 
 
 12 
 
 2'5 
 26'5 
 
 25 
 
 Gelatin-Carbonit. 
 
 N.G 25*5 
 
 C.C 7 
 
 AmNOg .. v 41-5 
 Glycerine and Gelatine 7*0 
 NaCl 25*3 
 
 Gelatin-Wetterastralit I. 
 
 16 
 4 
 
 Dinitrochlorhydrin 
 
 N.G 
 
 C.C 
 
 M.N.T i 
 
 D.N.T 2 
 
 Potato meal 8 
 
 W.M. 
 AmNOg 
 NaNO 3 
 Am. Ox. 
 NaCl . . 
 Oil 
 
 5 
 40 
 
 75 
 2*5 
 14*0 
 
 2 
 
 This latter explosive probably constitutes a record in 
 complexity of composition. 
 
 Austrian Explosives. The Austrian coal fields are only 
 of small extent, and the manufacture of explosives is a 
 Government monopoly. As a result only two explosives 
 are made for use in coal mines. They are Dynammon and 
 Wetter-Dynammon, and have the composition 
 
 AmNOg 
 
 KNOg 
 
 C 
 
 Dynammon. 
 .. 87 
 
 13 
 
 Wetter-Dynammon. 
 
 94 
 
 2 
 
 4 
 
 Belgian Explosives. A considerable number of 
 
140 
 
 EXPLOSIVES 
 
 explosives are on the Belgian I,ist of Explosifs S.G.P., of 
 which the following are typical examples : 
 
 Dynamite Antigrisouteuse II. Grisoutite. 
 
 N.G. 
 
 W.M. 
 
 Na 2 SO 4 .ioH 2 
 
 MgS0 4 .7H 2 
 
 Charge limite 
 
 N.G. 
 KNO 3 
 Ba(N0 3 ) 2 . . 
 Flour 
 Tan Meal 
 Na 2 CO 3 . . 
 Charge limite 
 
 N.G. 
 
 T.N.T. 
 
 KC10 4 . . 
 
 AmClO 4 . . 
 
 AmNO 3 . . 
 
 NaNO 3 . . 
 
 Flour 
 
 Glycerine gelatine 
 
 W.M. 
 
 NaCl 
 
 Charge limite 
 
 44 
 
 . 12 
 
 44 
 650 grams 
 
 44 
 
 12 
 
 44 
 300 grams. 
 
 Kohlen Carbonite. Minite. 
 
 25 
 
 34 
 
 i 
 
 25 
 
 35 
 
 39*5 
 
 '5 "5 
 
 . . 9 grams 750 grams. 
 
 Permonite S.G.P. Yonckite 10 bis. 
 
 .. 6 
 
 7 IO 
 
 29*5 
 
 4 
 3 
 3 
 
 24-5 
 900 grains 
 
 25 
 30 
 15 
 
 20 
 
 A large number of ammonium nitrate explosives are also 
 on the list of explosifs S.G.P. , of which the following table 
 gives a few typical examples : 
 
 Explosive. 
 
 n 
 
 | 
 
 0* 
 
 1 
 
 | 
 
 o" 
 9 
 
 | 
 
 d 
 
 ts 9 
 11 
 
 
 H 
 
 Q 
 
 
 M 
 
 fc 
 
 
 o J- 
 
 
 
 
 
 
 
 j 
 
 
 Densite 4 . . 
 Densite 3 . . 
 Favier 2 bis. 
 
 19 
 
 4 
 
 2-4 
 
 18 
 74 
 
 45*5 
 
 22 
 
 ~~* 
 
 2O 
 
 850 
 700 
 500 
 
 Fractorite B. 
 
 
 
 2'8 
 
 75 
 
 
 
 
 
 2*2 
 
 2O 
 
 450 
 
SAFETY COAL MINE EXPLOSIVES 141 
 
 A calcium silicide explosive, Sabulite Antigrisouteuse, 
 is also on the list, and has the composition 
 
 T.N.T 6 
 
 AmNO 3 54 
 
 KNO 3 22 
 
 Ca 2 Si 5 
 
 AmCl 13 
 
 French Explosives. The French explosifs de surete, 
 or explosifs antigrisouteuses, are defined by calculation of 
 temperature of explosion, and are divided into two classes, 
 viz. " Grisounites roches," with a temperature of explosion 
 of between 1500 C. and 1900 C., which can only be used in 
 rock, and Grisounites couches with a temperature of ex- 
 plosion below 1500 C. which can be used in coal. The 
 following are a few examples : 
 
 Explosif. 
 
 M.N.N. 
 
 D.N.N. 
 
 T.N.N. 
 
 AmNO,. 
 
 NaNO 3 . 
 
 KN0 3 . 
 
 N i a, bis.couche 
 
 _ 
 
 _ 
 
 5 
 
 95 
 
 _ 
 
 _ 
 
 N 4 couche 
 
 
 
 - 
 
 5 
 
 90 
 
 
 
 5 
 
 N ib, bis. roche 
 
 . 
 
 8'5 
 
 
 91'5 
 
 
 
 
 N ic, bis. roche 
 
 . 
 
 I2'6 
 
 . 
 
 87-4 
 
 
 
 N 2 roche . . 
 
 2O 
 
 
 
 
 
 
 80 
 
 
 N 3 roche . . 
 
 
 
 
 
 27 
 
 15 
 
 58 
 
 
 
 LITERATURE 
 COMMISSIONS 
 
 A summary of the reports of the various commissions first appointed 
 to inquire into the use of Explosives in coal mines will be found in " Revue 
 Universelle des Mines," 2nd Series, vols. 18 and 19 (Liege, 1886). The 
 British Report was published as an official document, " Final Report of 
 H.M. Commissioners Appointed to Inquire into Accidents in Mines " (1886), 
 and the French Report in " Annales des Mines," 1888, and in " Congrds 
 International des Mines," 1889. 
 
 FLAME 
 
 C. E. Bichel, " Testing Explosives," English translation by A. Larsen, 
 London, 1905. 
 
 J.C.S.I., 1899, p. 7. 
 
 S.S., 1908, p. 408 ; 1909, pp. 323, 343. 
 
 P.S., 1910, p. 164. 
 
 Bulletin of the U.S. Bureau of Mines, No. 66. 
 
 Reproductions of flame photographs will also be found in A. Marshall, 
 " Explosives," London, 1917. 
 
142 EXPLOSIVES 
 
 GALLERIES 
 
 The U.S.A. Gallery is described in detail in Bulletin of the Bureau of 
 Mines, No. 15. This publication contains much interesting information 
 on " Permissible Explosives," and together with Bulletin No. 66 should be 
 studied by any one interested in American conditions. Unfortunately it 
 does not give the composition of the explosives used. 
 
 The Brit] ;h Gallery at Rotherham is described with drawings in A.R., 
 1912, p. 83. 
 
 An account of the Continental galleries will be found in A. Marshall, 
 " Explosives," and P. F. Chalons, " Les Explosifs Modernes." 
 
 The effect of turbulence on the ignition of gas mixtures is discussed 
 in Soc., 1919, p. 87. 
 
 WRAPPERS 
 " VIII. International Congress of Applied Chemistry," vol. iv. p. 138. 
 
 SIZE OF BORE HOLE AND GALLERY 
 S.S., 1910, pp. 221, 225 ; 1911, pp. 321, 344, 371. 
 
 PERMITTED EXPLOSIVES 
 
 The composition of the explosives on the British Permitted List will be 
 found in the following " Explosives in Coal Mines Orders " : 
 
 September ist, 1913. February 3rd, 1916. 
 
 February loth, 1914. April I4th, 1916. 
 
 April 7th, 1914. April 26th, 1916. 
 
 May I3th, 1914. September 21 st, 1916. 
 
 June 22nd, 1914. November 2ist, 1916. 
 
 August 29th, 1914. May 9th, 1917. 
 
 January I5th, 1915. November 5th, 1917. 
 
 January 28th, 1915. May 3oth, 1918. 
 
 April ist, 1915. August 2nd, 1918. 
 
 July 3rd, 1915. November 28th, 1918. 
 
 August i6th, 1915. January 25th, 1919. 
 
 The composition of a large number of continental explosives is given in 
 A. Marshall, " Explosives," London, 1917. 
 
SECTION VI. PERCUSSION CAPS, DETO- 
 NATORS AND FUZES 
 
 THE actual mechanism of detonation is uncertain, but it is 
 probably either a very rapid wave of compression raising the 
 temperature locally in successive layers, or it is a vibration 
 of the molecules of such a nature that it causes disruption 
 into more stable forms of matter. In any case, when the 
 majority of explosives burn the rate of burning increases 
 until it reaches detonation, the velocity of detonation then 
 remaining practically constant. 
 
 In order to be suitable for use as an initiator an explosive 
 must be of such a nature that the acceleration is very rapid, 
 burning passing into detonation in the least possible time. 
 Further, it must keep well, and although for some purposes 
 sensitiveness to shock is essential, this must not be so ex- 
 cessive that the manufacture and handling of the material 
 is accompanied by undue danger. 
 
 No chemical compound fulfils all these conditions, and 
 of the various ones that have been proposed from time to 
 time only two have been found suitable for practical purposes, 
 viz. mercury fulminate and lead azide. Of these mercury 
 fulminate possesses fair acceleration, and is not unduly 
 dangerous to handle when proper precautions are taken. 
 It, however, is expensive, does not keep well, and the mercury 
 fumes evolved during its explosion have a bad effect on brass 
 cartridge cases. Also, like all mercury compounds, it is very 
 poisonous, and consequently workers must be carefully pro- 
 tected from inhaling dust, and special means must be taken 
 to dispose of effluent such as wash water, which may contain 
 traces of mercury. This is particularly necessary when the 
 factory is situated near rivers containing fish. 
 
 I^ead azide, on the other hand, possesses excellent accelera- 
 tion, and keeps well. It is less sensitive than mercury 
 
144 EXPLOSIVES 
 
 fulminate when in small crystals, but, unlike fulminate, it 
 readily forms large crystals, and these are so sensitive that 
 they explode when touched even when under water. It is 
 somewhat less expensive and less poisonous than fulminate, 
 but, on the other hand, the plant required for its manufacture 
 is much more expensive. 
 
 Mercury fulminate is still the most used initiator, but 
 lead azide is coming into more general use, and probably 
 in the future will displace fulminate to a considerable extent. 
 The properties required of an initiator depend a good deal 
 on the conditions under which it is to be used. Blasting 
 charges are always fired by means of a fuze or an electric 
 current, so that, provided the initiator is sensitive to heat, 
 there is no need for it to be sensitive to shock. On the other 
 hand, except in the case of non-detonating explosives such 
 as gunpowder, it is required to detonate the explosive and not 
 merely to start combustion. Hence, detonators for blasting 
 purposes require to be powerful, as otherwise the charge will 
 either be merely ignited, or detonation will be incomplete. 
 
 Propellants, on the contrary, are not detonated, but 
 ignited, so that a weak initiator is used, this firing a priming 
 composition or " flaming mixture/' which in turn fires the 
 propellant. These flaming mixtures are of a very inflammable 
 nature, and consist usually either of fine grain gunpowder or 
 of antimony sulphide mixed with an oxidizing agent. In 
 the case of small arms only slight power is available, that 
 due to the fall of the hammer, so that an initiator very 
 sensitive to shock must be used. With quick-firing guns 
 more power is available. With heavy ordnance plenty of 
 power is available, so that great sensitiveness is not required, 
 and the initiator in this case usually contains no explosive 
 properly so called, but is more akin to match composition. 
 Naval guns and guns of position are frequently fired electri- 
 cally, so that sensitiveness to heat only is called for. 
 
 Mercury Fulminate, Hg(ONC) 2 .This is an endother- 
 mic compound, the heat of formation being 62*9 Cal. It 
 is always manufactured by the action of ethyl alcohol on a 
 solution of mercury in nitric acid. The reaction is a very 
 
 J 
 
PERCUSSION CAPS, DETONATORS AND FUZE 145 
 
 violent one, and in order to obtain a satisfactory yield the 
 manufacture must be carried out on what is practically 
 a laboratory scale, only about 3 Ibs. of fulminate being made 
 at a time. Several recipes have been published differing 
 only in minor details, but the following description gives a 
 good general idea of how the manufacture is usually carried 
 out. 
 
 The plant consists of glass bottles or retorts of about 
 50 litres capacity each, each being connected to a stoneware 
 or silica worm condenser and with a brick scrubbing tower. 
 Ample draught must be provided to draw off the fumes, as 
 they are very poisonous. They consist largely of nitrous 
 acid, aldehyde, ethyl nitrate, ethyl nitrite and unchanged 
 alcohol, and are highly inflammable. The process is carried 
 out by dissolving 500 grams of mercury in 4500 grams of 
 nitric acid (D = 1400) . The solution of mercuric nitrate thus 
 obtained is warmed or cooled to 25 C., and 5 litres of 
 94 per cent, spirit added. The reaction starts after about 
 15 minutes, and lasts for about three-quarters of an hour./ If, 
 however, the temperature of the nitrate solution has been 
 much below 25 C., it may be necessary to apply gentle heat 
 in order to start the reaction, whereas if the temperature has 
 exceeded 25 C., the reaction maybe uncontrollably violent. 
 XDuring the reaction the temperature rises to about 85 C., 
 and much liquid distils over and condenses.. TMs distillate 
 is not of great value, but can be used to replace part of the 
 spirit for the next batclju"* When the reaction is over the 
 contents of the vessel are allowed to cool, about i litre of 
 water is added, and the whole then poured out into a porcelain 
 dish, and the fulminate thoroughly washed with cold water, 
 first by decantation and then on a muslin filter. The wash 
 waters are collected, made alkaline with lime, and the 
 mercury thus precipitated, filtered off, and recovered. 
 About 10 per cent, of the total mercury used is recovered by 
 this means, and after the precipitated mercury has been 
 filtered off the liquors can usually be safely run to waste, 
 although, as a matter of safety, they should be dealt with 
 so that they do not find their way by infiltration into any 
 T. 10 
 
146 EXPLOSIVES 
 
 drinking water supply or into any stream stocked with 
 fish. 
 
 The fulminate thus obtained is quite safe so long as it 
 is preserved wet. It is only dried immediately before use, 
 the drying being carried out by spreading it on paper trays 
 in a stove heated to 35 C. These stoves usually take 100 Ibs. , 
 and great care must be taken not to unload them until the 
 fulminate is quite cold, fulminate being much more sensitive 
 when warm. Thus obtained, it forms a grey powder, the 
 yield being about 650 grams from 500 grams of mercury^x 
 which corresponds to about 90 per cent, of theory. If a 
 little metallic copper and hydrochloric acid is added to 
 the nitrate solution just before the spirit, an almost white 
 product is obtained, but this is less pure than the grey. 
 
 -Culminate has a specific gravity of about 4-4, and 100 c.c. 
 of water dissolves "07 gram at 13 C., "17 gram at 49 C., 
 and *8 gram at 100 C. It can be quantitatively estimated 
 by titration with thiosulphate 
 
 N N 
 
 Lead Azide, || ^>N Pb N/ ||. In making lead azide, 
 
 W ^ 
 
 metallic sodium is first converted into sodamide, NaNH 2 , 
 by heating it to 350 C. and then passing a brisk current of 
 dry ammonia gas over the surface. Considerable heat is 
 evolved, and by using a fairly brisk stream of ammonia the 
 temperature is maintained during the reaction without 
 external heating. The reaction is easily followed by testing 
 the gas at the exit, a rapid falling off in the hydrogen content 
 indicating that the whole of the sodium has been used up. 
 The sodamide thus formed is next converted into sodium 
 azide by heating it to i5o-25o C. in a stream of nitrous 
 oxide (laughing gas) 
 
 2NaNH 2 + N 2 O = NaN 3 + NaOH + NH 3 
 
 The sodium azide thus formed is dissolved in water, and 
 lead salt thrown down by double decomposition with lead 
 
PERCUSSION CAPS, DETONATORS AND FVZE 147 
 
 acetate. It forms a white crystalline powder which is almost 
 insoluble in cold water, and not much more so in hot water. 
 It has a tendency to form large crystals, and these may 
 explode spontaneously even when under water. Small or 
 moderate crystals are less sensitive to shock and heat than 
 mercury fulminate, and owing to its high acceleration it is 
 more effective as an initiator. Thus it has been found that 
 whereas -25 gram of fulminate was required to detonate 
 trinitrotoluol, "05 gram of lead azide was sufficient under 
 the same conditions. It is chiefly used in conjunction with 
 tetryl or T.N.T. in composite detonators. 
 
 Other sensitive chemical compounds, such as diazo- 
 benzene nitrate, nitrodiazobenzene nitrate, lead picrate and 
 nitrogen sulphide have been proposed for use as initiators 
 from time to time, but with no success, as in all cases the 
 acceleration is too slow. 
 
 Caps. Cap composition for small arms is usually a 
 mixture of fulminate of mercury, potassium chlorate, 
 antimony sulphide and other oxidizable matter to which 
 ground glass is frequently added to increase the sensitiveness. 
 For ordnance, where more power is available, the fulminate is 
 usually omitted. Sometimes gelatine or gum arabic is 
 added to give coherence to the composition, but the addition 
 is by no means necessary unless the mixing is done wet. 
 
 The following table shows the composition of some 
 British and Austrian caps : 
 
 
 British 
 S.M. 
 (Cordite). 
 
 British 
 (Cordite). 
 
 British 
 Q.F. 
 (Cordite). 
 
 Austrian, 
 for rifles. 
 
 Austrian, 
 for shot 
 guns. 
 
 Austrian, 
 for friction 
 tubes. 
 
 Fulminate . . 
 
 8 
 
 19 
 
 
 13*7 
 
 33'9 
 
 
 KC10 3 ... 14 
 
 33'3 
 
 12 
 
 41*5 
 
 21-6 
 
 66-2 
 
 Sb 2 S 3 .. 18 
 
 42-9 
 
 18 
 
 33'4 
 
 
 
 33*1 
 
 Meal G.P. . . ! i 
 
 2-4 
 
 I 
 
 
 
 
 
 S i i 
 
 2-4 
 
 I 
 
 
 
 
 
 
 
 Glass 
 
 
 I 
 
 10-7 
 
 43*2 
 
 
 
 Gum 
 
 
 
 
 
 
 
 
 
 '7 
 
 Gelatine . . 
 
 
 
 
 
 " 
 
 '7 
 
 l'3 
 
 
 Herz has suggested the use of copper ammonium thio- 
 sulphate, prepared by treating copper ammonium sulphate 
 
148 EXPLOSIVES 
 
 with sodium thiosulphate, and lead thiosulphate in con- 
 junction with potassium chlorate, and has claimed good 
 results with the following mixtures, although they do not 
 seem to have come into use : 
 
 KC10 3 57-3 54-5 51-5 53 
 
 Cu(NH 3 ) 4 S 2 O 3 .. . . 427 40-5 37-1 27-5 
 
 PbS 2 3 .. 7-4 5-5 
 
 Sb 2 S 3 . . . . . . 11*0 
 
 Glass . . . . . . 4*0 4*0 3*0 
 
 In preparing cap composition the powdered ingredients 
 are sieved separately and then mixed, either in the wet or 
 in the dry state. In Great Britain and in France the mixing 
 is usually done dry, but in Austria and Germany wet mixing 
 is frequently preferred. When the mixing is carried out 
 in the wet way it is absolutely necessary to add gum or other 
 binding material to prevent the ingredients separating. 
 Sufficient water, in which the binding material has been 
 dissolved, must be added to form a thick mud, but an exces- 
 sive amount must be avoided, as if present it will carry away 
 some of the chlorate and also interfere with the granulating 
 of the material. Too little water, on the other hand, renders 
 the composition dangerous. In any case, great care must be 
 taken that none of the composition gets on to the edge of the 
 mixing dish and becomes dry. In order to avoid loss of 
 chlorate by solution in the water, alcohol is sometimes added, 
 as by this means the solubility of the chlorate is greatly 
 lowered. In any case, after mixing the composition is 
 granulated by rubbing through horse-hair or silk sieves, and 
 then dried and sifted. It is not advisable to load the caps 
 with the wet composition and then dry them as was done at 
 one time, as under these conditions the composition is apt to 
 form a hard mass which is unduly sensitive. For use in 
 the wet process the fulminate is not, of course, dried, the 
 paste containing about 15 per cent, of water being used. 
 When mixing by the dry method the ingredients, with the 
 exception of the fulminate, are first mixed, the fulminate 
 then added and the mixing repeated. The object of this 
 
PERCUSSION CAPS, DETONATORS AND FUZE 149 
 
 procedure is, of course, to do as much of the mixing as 
 possible before adding the dangerous fulminate. Owing 
 to the dangerous nature of the substances dealt with the 
 mixing is done in very small quantities, from one-half pound 
 to two pounds being the usual charge. The plant used is 
 very simple, and consists either of a papier mache drum 
 revolved by hand, or of a cloth or light leather " jelly-bag." 
 When the drum method is used the preliminary mixing of 
 the ingredients other than the fulminate is assisted by the 
 addition of soft rubber balls, thus converting the papier 
 mache drum into a sort of crude ball mill. These balls are 
 removed, however, before the fulminate is added. 
 
 The " jelly-bag " is probably the best and most used 
 mixing machine, and is shown in Fig. 22. It consists of a 
 conical bag of cloth or light leather, the upper and wider end 
 being attached to a frame. To the inside of the apex is 
 attached a cord carried over pulleys to the operator, who is 
 at a safe distance and behind a suitable screen. By pulling 
 the cord the bottom of the bag is raised, thus turning over 
 the contents and mixing them, a movable stop being pro- 
 vided to prevent the cord being pulled too far and thus causing 
 the contents of the bag to be spilt. On releasing the cord 
 the bag is returned to its normal position, either by the 
 weight of the composition or by a counterpoise. Some- 
 times rubber discs are added to make the mixing more 
 thorough. During the mixing a vessel of water is placed 
 under the bag to catch any composition which may be 
 accidentally upset, but when mixing is complete this is 
 replaced by a paper box. The operator then retires behind 
 the screen, removes the movable stop, and, by pulling the 
 cord, turns the bag outside in, the composition being guided 
 into the cardboard box by the conical funnel surrounding 
 the bag. The method is extremely safe, as even should a 
 charge explode during mixing the operator is well pro- 
 tected. To allow the operator to watch the bag a narrow 
 slit may be made in the screen, but a window of Triplex 
 safety glass would probably be more satisfactory. This 
 has been tested officially with most encouraging results, 
 
150 
 
 EXPLOSIVES 
 
 a 
 
 n" "D 
 
 FIG. 22. Jelly-bag Mixing Machine for Cap and Detonator Composition. 
 
PERCUSSION CAPS, DETONATORS AND FUZE 151 
 
 the following description of the test being taken from 
 4 ..,19x7: 
 
 " A block of Triplex Safety Glass 2| in. thick was securely 
 fixed by |-in. angle iron plates to a screen of timber 3 in. thick, 
 and 4500 grains weight of fulminate of mercury was fired close 
 underneath the glass. The result was to shatter the wooden 
 screen work, large pieces of timber flying 150-200 ft. in the 
 air, but the Triplex glass, although cracked in all directions, 
 was found to be absolutely whole a clear demonstration 
 of the great protection to an operator that would be afforded 
 by this glass during work with detonators." 
 
 The metallic cap cases are stamped out of sheet copper, 
 
 FIG. 23. Percussion Cap Filling Machine. 
 
 or, less frequently, brass, and are varnished internally. The 
 composition is filled in in the following manner : The cases 
 are placed in depressions in a bronze plate, called a " hand," 
 1000 being the usual number. Another plate, usually 
 made of ebonite, is then placed on the " hand," this plate 
 having perforations corresponding to the depressions in 
 the " hand," but is placed in such a position that the rows 
 of perforations come between the rows of depressions 
 (Fig. 23). The thickness of the upper plate is so chosen that 
 the correct weight of composition just fills the perforations. 
 Rather more than the weight of composition required to fill 
 1000 caps is then placed on the upper plate and brushed into 
 
152 EXPLOSIVES 
 
 the perforations so as to fill them, any excess of composition 
 being removed with a soft brush. The operator then retires 
 behind a screen and slides the upper plate along the lower 
 until the perforations correspond with the depressions, and 
 the composition falls into the caps. The upper plate is 
 then removed, and the "hand" placed in a hydraulic or 
 mechanical press provided with a number of pistons, each 
 piston entering one cap. The pressure applied is about 
 200-250 Ibs. per cap, and usually there are sufficient pistons 
 in each press to press one or two rows of caps at a time, the 
 " hand " being moved forward in order to allow the next 
 row to be treated. After pressing, any loose composition 
 is fanned away and the caps then varnished by placing a 
 single drop of alcoholic shellac on the top of the composition, 
 after which the alcohol is dried off at a low temperature. If 
 the caps are to be transported a tin disc must be inserted into 
 each (see page 14), and this is frequently done in any case. 
 It is fixed by pressing in presses similar to those used for the 
 composition, and is subsequently varnished. 
 
 Caps only contain about *5-'6 grain (say, -04 gram) of 
 composition, so that the amount of composition required 
 for a " hand " holding 1000 caps does not exceed 50 grams. 
 Consequently it is not difficult to provide adequate pro- 
 tection in the way of shields for the workers. Undoubtedly 
 Triplex Safety Glass windows in these shields will prove a 
 great convenience by allowing the operations in progress to 
 be watched, while at the same time providing adequate 
 protection. 
 
 Officially, caps are defined as containing not more than 
 half a grain of composition, or not more than *6 grain if 
 it contains less than 25 per cent, of fulminate. If they 
 contain more they must be treated as detonators (see page 
 14). Caps can be roughly tested by observing the marks 
 produced when they are flashed against a sheet of white 
 paper at a given distance, or, more accurately, by a modifica- 
 tion of the crusher gauge. More elaborate methods deter- 
 mine the length or duration of the flame, and the tempera- 
 ture of explosion is determined by an electrical or optical 
 
PERCUSSION CAPS, DETONATORS AND FUZE 153 
 
 pyrometer. References to these methods will be found at 
 the end of the section. 
 
 The use of mercury and antimony is objectionable with 
 brass cartridge cases, as these metals have a bad effect on the 
 brass, but so far no satisfactory substitutes seem to have 
 been discovered. In the same way, the chloride resulting 
 from the chlorate causes rusting. An all-organic initiator 
 would be a valuable discovery, but so far has not been 
 attained. 
 
 Detonators. Detonators being required to produce 
 detonation and not ignition require to be much more power- 
 ful than caps. Until comparatively recently they have been 
 chiefly composed of a mixture of 80 per cent, of fulminate of 
 mercury and 20 per cent, of potassium chlorate rammed into 
 copper tubes, although a great many French detonators 
 contain only fulminate. In recent years composite de- 
 tonators have been largely used in which T.N:T. or, 
 better, tetryl is first pressed into the case and a detonating 
 composition of fulminate and chlorate or of lead azide 
 pressed on to the top of this. These detonators are practi- 
 cally a detonator and primer combined, the fulminate or 
 azide detonating the T.N.T., or tetryl, which in turn 
 detonates the cartridge. They have the advantage of being 
 cheaper than non-composite detonators, and of involving 
 the use of much less of the dangerous fulminate. The small 
 amount of fulminate used, however, has one disadvantage, 
 and that is that the effect of deterioration is much more 
 marked. Fulminate does not keep well, and if the amount 
 is reduced to a minimum, as is the case in composite 
 detonators, there is much greater chance of irregular results 
 being obtained. This objection does not, of course, apply 
 to composite detonators made up with lead azide in place of 
 fulminate. 
 
 The size of detonators has been standardized in all 
 countries, and the following table shows the sizes, together 
 with the charge of fulminate-chlorate mixture (80 per cent, 
 fulminate), and the charges for a few composite detonators 
 of equal strength : 
 
154 
 
 EXPLOSIVES 
 
 
 External dimensions. 
 
 Charge (grams). 
 
 No. 
 
 Length. 
 
 Diameter. 
 
 Fulminate KC1O 3 . 
 
 T.N.T. or Tetryl. 
 
 Fulminate. 
 
 
 mm. 
 
 mm. 
 
 "3 
 
 
 
 I 
 
 16 
 
 5'5 
 
 '4 
 
 
 
 
 
 2 
 
 22 
 
 5'5 
 
 '54 
 
 
 
 
 
 3 
 
 26 
 
 5*5 
 
 6 5 
 
 1 
 
 4 
 
 28 
 
 6-0 
 
 8 
 
 
 - . 
 
 5 
 
 30-32 
 
 6-0 
 
 ro 
 
 '3 
 
 '3 
 
 6 
 
 35 
 
 6-0 
 
 1*5 
 
 4 
 
 "4 
 
 7 
 
 40-45 6-0 
 
 2'0 
 
 '75 
 
 '5 
 
 8 
 
 5-55 6-7 
 
 2-5 '9 
 
 '5 
 
 Of these Nos. 5 and 6 are usually used for nitroglycerine 
 explosives, and No. 7 for ammonium nitrate explosives. 
 No. 8 is not much used, although probably better results 
 would be obtained by employing somewhat stronger 
 detonators than is the custom. 
 
 French composite detonators have been manufactured 
 containing picric acid, but they are somewhat uncertain, 
 and, in any case, picric acid in contact with copper is most 
 objectionable. The copper tubes for detonators are stamped 
 out of sheet copper, and on account of the dimensions only 
 the very best soft copper can be used. The methods em- 
 ployed in the filling operation are much the same as those 
 used in rilling caps. The empty cases are filled into per- 
 forations in an ebonite plate, each perforation being lined 
 with brass to prevent distortion, and being of such a size, 
 that the detonator is a snug but not a tight fit. Usually 
 only 100 detonators are treated at a time, the charge for 
 each being measured out in the perforations of a sliding plate 
 in exactly the same way as when caps are being filled. The 
 pressing is carried out in presses with 100 pistons, each 
 piston being a loose fit in the detonator so as to avoid 
 friction. The pressure employed is about 250 kg. per cm. 2 
 (60 kg. per detonator), and this raises the density of the 
 charge to about 2*2. By using higher pressure higher 
 density is attained, but the effectiveness of the detonator 
 falls off considerably. After pressing they are rumbled with 
 sawdust to remove any loose composition, and then packed. 
 
PERCUSSION CAPS, DETONATORS AND FUZE 155 
 
 The British regulations for packing specify that the 
 detonators shall be packed in sawdust in tin boxes lined with 
 felt or paper, and that the ends shall rest against a felt pad. 
 These tin boxes are packed in outer cases, and if the package 
 thus formed contains over 1000 detonators the outer case 
 must be double, with a space of not less than 3 in. between 
 the walls. If over 5000 detonators are in one case, the case 
 must be provided with handles for lifting, and the maximum 
 number of detonators that can be packed in any case is 
 10,000. 
 
 Detonators in which the one end is left open are fired 
 by means of a safety fuze, the end of the fuse being pushed 
 down until it touches the composition and then held in 
 place by constricting the mouth of the detonator with a 
 pair of pliers. Electrical firing, however, is rapidly increas- 
 ing, and detonators for this purpose are known as electric 
 detonators, and are of two types, viz. high tension and low 
 tension. In the high-tension detonators firing is brought 
 about by an electric spark passing between two points and 
 igniting a flaming mixture. They are not much used as, 
 under working conditions, the high-tension current needed 
 is liable to short circuit, and the detonators cannot be tested 
 before use. I/ow-tension detonators are actuated by the 
 electrical heating of a fine platinum wire, only a low voltage 
 current (2-3 volts) being required. They can be tested 
 before use by determining their resistance on a Wheatstone 
 bridge, a sensitive galvanometer and a very small current 
 being used. The platinum wire might actually be embedded 
 in the composition, but this system would be unreliable, as 
 it would probably be broken during pressing, and, in any case, 
 there would be danger of friction being set up through move- 
 ments of the free ends. The system always employed is to 
 solder a very fine platinum wire on to the leads which are 
 in turn cemented into the open mouth of the detonator by 
 means of sulphur or bitumen. Previous to this, however, 
 a bead of a flaming mixture of sulphide of antimony and 
 chlorate of potash is melted on to the platinum wire. In 
 use, the heating of the platinum wire ignites this flaming 
 
156 EXPLOSIVES 
 
 mixture, which in turn ignites the detonator composition. 
 As a source of current a small dynamo is generally used, the 
 armature being revolved by depressing a plunger, this being 
 geared on to the armature by a rack and spur-wheel. When 
 almost at the bottom of its stroke this plunger closes the 
 circuit with the detonator, this arrangement being provided 
 so that no current passes until the speed of the armature, 
 and hence the voltage, has had time to reach a sufficient 
 magnitude to make ignition certain. 
 
 Several methods have been proposed for testing de- 
 tonators, such as the lead block test, in which the detonator 
 is fired in a lead block much the same as the Trauzl block 
 (see Section VIII.) only smaller ; the crater test, in which 
 the detonators are fired in contact with a plate of J-in. lead 
 and the craters produced compared ; and the nail test. This 
 latter is the best, and is carried out as follows : The detonator 
 is attached to a 4-in. wire nail by means of a copper wire round 
 its centre, but is prevented from actually touching the nail 
 by two bands of copper wire placed round the detonator near 
 each end, the wire being -025 in. diameter (23 B.W.G.). The 
 bottom of the detonator points towards the head of the nail, 
 but is if in. from it. The whole is then suspended, nail 
 upwards, by the leads, as shown in Fig. 24, and then fired, 
 care being taken that the nail cannot be hurled against any 
 hard substance. The angle of deformation of the nail is 
 taken as a measure of the strength of the detonator. 
 
 Safety Fuze. The object of safety fuze is to ignite the 
 detonator at an interval of time after the fuze has been 
 lighted, thus allowing the shot firer to get to a safe distance. 
 A fuze must be reliable, and not be apt to go out ; it must be 
 capable of burning under water when subaqueous blasting 
 is being carried out ; and must burn at a constant rate so 
 that the explosion of the charge does not take place before 
 the firer has attained a place of safety. All safety fuzes 
 consist of a core of fine grain gunpowder enclosed in an 
 outer case of jute, the outer case being more or less water- 
 proofed according to the type of fuze desired. To prevent 
 the case smouldering the jute is frequently impregnated with 
 
PERCUSSION CAPS, DETONATORS AND FUZE 157 
 
 ammonium phosphate, or other suitable neutral salt . Modern 
 safety fuze has a very steady rate of burning of about 
 2 ft. per minute. 
 
 The plant necessary for " spinning " fuze is shown 
 diagrammatically in Fig. 25, and consists of a hopper contain- 
 ing gunpowder, the lower end of which terminates in a fine 
 nozzle. A frame containing from seven to ten reels of jute 
 yarn revolves round the hopper, the yarn being carried down 
 
 u 
 
 FIG. 24. Testing Detonators. 
 
 FIG. 25. Fuze Spinning 
 
 close to the nozzle. As the powder flows out of the nozzle the 
 revolving reels enclose it in a loose spiral of thread which 
 then passes through a narrow tube. As it issues from the 
 lower end of this tube another set of reels revolving in the 
 opposite direction spins another spiral of thread round it, 
 after which the fuze is wound on a drum and is ready for 
 waterproofing, etc. In order to maintain an even flow of 
 powder from the hopper a thread is sometimes made to 
 pass through it, the motion of this thread preventing the 
 
158 EXPLOSIVES 
 
 orfice becoming choked, and at the same time assuring a 
 more equal flow of powder. 
 
 For ordinary use in damp situations sufficient water- 
 proofing is attained by passing the fuze through tar, after 
 which it is wound with tape, the turns overlapping, and then 
 again tarred. For subaqueous work, however, the fuze is 
 usually first treated with a priming coat composed of 
 Stockholm tar and low grade gutta-percha, and then coated 
 with pure gutta-percha. To preserve this from mechanical 
 damage it is usually wound with tarred yarn. 
 
 Instantaneous Fuze. This is a rapidly burning fuze 
 intended for firing several shots simultaneously. It consists 
 of a wick impregnated with meal powder and then loosely 
 spun over with yarn. The rate of burning is about 300 ft. 
 per second, but it is little used now, having been replaced 
 by electric detonators or detonating fuze. 
 
 Quick-Match. This is much the same as instantaneous 
 fuze, but is unwound so that its rate of burning is much 
 slower, viz. about 15 ft. per minute. It is used to some 
 extent in fireworks, e.g. for firing the bursting charge in the 
 heads of rockets. 
 
 Slow-Match . This is a loosely woven hemp cord slightly 
 impregnated with potassium nitrate, so that it smoulders 
 slowly. It is used chiefly in conjunction with pyrophoric 
 alloys for cigarette lighters, and takes the place of the 
 tinder used with the old-fashioned " flint and steel." It is 
 also used to some extent for delayed action mines in warfare. 
 
 Detonating Fuze. This is practically a very narrow 
 cartridge of some detonating explosive in a metal case, 
 T.N.T. or tetryl being the explosive most used. It is usually 
 about 4 mm. in diameter, and is put up in coils of 50 ft. or 
 more. A guncotton detonating fuze was at one time made 
 in France by filling dry powdered guncotton in a lead pipe 
 15*5 mm. external diameter and 12 mm. internal diameter. 
 The ends of the pipe were then closed and the whole drawn 
 out by passing through a series of holes in a draw-plate in 
 much the same way that wire is drawn. These holes 
 diminished in diameter from 15*5 to 5 mm. by intervals of 
 
PERCUSSION CAPS, DETONATORS AND FUZE 159 
 
 5 mm., and then from 5 mm. to 4 mm. by intervals of 
 2 mm. This fuze was said to give satisfactory results, 
 but never came into general use, and has now been displaced 
 by fuzes containing T.N.T. These are made by sucking 
 molten T.N.T. into a lead pipe by means of a vacuum, the 
 pipe being kept hot in a water-bath. After cooling, the fuze 
 is drawn out through draw-plates, but as much narrower 
 tubes can be filled by sucking in a liquid than is the case 
 when they are loaded with a solid, like guncotton, the same 
 number of drawings is not necessary. The rate of detona- 
 tion is very constant, about 5000 metres per second, and the 
 fuze is much used for determining the rate of detonation of 
 explosives (Section VIII.). It is also used for the simul- 
 taneous firing of several shots, and in warfare attempts have 
 been made to employ it for the destruction of wire entangle- 
 ments. It is fired by means of a detonator. It should be 
 noted that pure T.N.T. must be used for the manufacture of 
 fuze, as the crude product is apt to become plastic on cooling, 
 and will then not detonate properly. 
 
 A somewhat different type of detonating fuze is used in 
 the Austrian army. This consists of threads impregnated 
 with mercury fulminate phlegmatized by the addition of 
 20 per cent, of paraffin wax. When fired with a suitable 
 detonator its rate of detonation is about 6000 metres per 
 second, but if ignited it burns quietly, unless it becomes 
 hot enough for the paraifin to meet and run away from the 
 fulminate. 
 
 Shell Fuzes. These are of two types, viz. time fuzes 
 and percussion fuzes, the former being intended to explode 
 the shell in the air after it has travelled a certain distance, 
 and the latter to explode it on striking. Shells with time 
 fuzes are frequently also fitted with percussion fuzes, so that 
 they explode on striking should the time fuze fail, whereas 
 percussion fuzes are often connected with a short time fuze 
 so that explosion only takes place a short time after the 
 shell has struck, thus giving it time to penetrate. This type 
 of fuze, delayed action fuze, is much used for armour piercing 
 shell, and for the bombardment of deep dugouts, as an 
 
160 EXPLOSIVES 
 
 ordinary percussion fuze would explode the shell on the 
 surface, and thus do comparatively little damage. 
 
 Time fuzes consist of one or more rings of slow-burning 
 gunpowder situated in the nose of the shell, and com- 
 municating with the burster charge. The fuze is fired by a 
 simple cap actuated by the shock of the propellant. The 
 rings are movable, and by rotating them the length of the 
 powder train between the firing cap and the burster charge 
 can be altered. The rings are graduated with a scale 
 showing the number of yards of travel of the shell, and the 
 fuze is set for the given range before the shell is inserted in 
 the gun. 
 
 Percussion fuzes are set either in the nose or in the base 
 of the shell, and are actuated by the sudden retardation 
 when the shell strikes, driving a pin on to a cap. To prevent 
 the shock of the discharge actuating the pin, special safety 
 arrangements are provided. These may take several forms, 
 e.g. the pin may be held back by a powerful spring, the 
 resistance of which can only be overcome by a very violent 
 blow on the nose of the shell, or it can be provided with a 
 safety catch which is only released by the centrifugal force 
 set up by the rotation of the shell. As stated above, the 
 percussion fuze is often made to fire a short time fuze in 
 order to allow the projectile to penetrate before bursting. 
 
 LITERATURE 
 
 MERCURY FULMINATE 
 
 " Das Knallquecksilber u. Ahnliche Sprengstoffe," R. Knoll, Vienna, 
 1908. 
 
 S.S., 1911, pp. 4, 28, 44. 
 
 LEAD AZIDE 
 
 Z.ang., 1911, p. 2089; 1914, p. 335. B. 25, p. 2084. 5.S., 1911, p. 417; 
 1914, p. 242. 
 
 PERCUSSION CAPS 
 
 Hagen describes the wet mixing process in detail in S.5., 1911, pp. 201, 
 224, 243, 265, 283, 308, and the filling of caps, with drawings of the plant 
 required, in S.S., 1912, pp. 277, 297, 322, 343, 367, 388, 411, 431, 449. 
 
 Herz gives details of trials with cap composition containing thiocyanates 
 in 5.S., 1912, p. 284. 
 
 The following references are the methods of testing caps: /. S.C.I., 1905, 
 p. 381 ; 1906, p. 241. 
 
PERCUSSION CAPS, DETONATORS AND FUZE 161 
 
 Compositions for use with friction tubes, and flaming mixtures as used 
 for British Naval and Military purposes, are described in the Official 
 Publications, viz. " Treatise on Ammunition " (Military), and " Handbook 
 on Ammunition " (Naval). 
 
 DETONATORS 
 
 S.5., 1907, pp. 4, 245; 1913, pp. 167, 190, 209. 
 
 P.S., xii. p. 134. 
 
 The above refer to fulminate and fulminate composite detonators. 
 Lead azide detonators are described in Z. ang., 1911, 2098; S.S., 1911, 
 p. 417 ; 1913, pp. 209, 210 ; 1914, p. 242 ; D.R.P. 196,824, 238,942. 
 
 A very interesting critical examination of the various methods of testing 
 detonators is given in Bulletin of the American Bureau of Mines, No. 59. 
 In this publication the methods are described in detail. 
 
 SAFETY FUZE 
 
 The manufacture of safety fuze, together with illustrations of the plant 
 used, is treated in detail inS.iS., 1910, pp. 87, 107, 130, 148 ; 1913, pp. 145, 
 167. 
 
 The X-ray examination of safety fuze for discontinuity of the powder 
 core is suggested in /. S.C.I., 1903, 1224. 
 
 DETONATING FUZE 
 
 S.S., 1907, p. 173 ; 1910, p. 169 ; 1913, p. 312. 
 
 See also Chalons, " Les Explosifs Modernes," Paris, 1911, p. 424. 
 
 SHELL FUZES 
 
 These are fully illustrated and described in the Official Publications. 
 " Treatise on Ammunition " and " Handbook on Ammunition." 
 
 Also in R. Willie, " Mechanische Zeitziinder," Berlin, 1911. D. T. 
 Hamilton, " Shrapnel Shell Manufacture," New York, 1915. 
 
 ACCIDENTS 
 
 Accounts of recent accidents that have occurred in Great Britain in 
 connection with the manufacture of fulminate, detonators, etc., will be 
 found in S.7?., 186, 188, 196, 199. 
 
 T. II 
 
SECTION VII. MATCHES, PYROPHORIC 
 ALLOYS AND PYROTECHNY 
 
 MATCHES 
 
 UNTII, 1805 the only mechanical means of obtaining fire as 
 distinguished from the use of the burning glass, consisted in 
 striking sparks with flint and steel, and by this means 
 igniting tinder. Curiously enough during recent years this 
 method has again come to the front in a modified form, the 
 flint being replaced by special pyrophoric alloys, and the 
 tinder by slow-match or by a wick soaked in petrol. In 
 1805 Chancel introduced splints of wood tipped with a 
 mixture of sugar and potassium chlorate mixed with gum, 
 these being ignited on a pad of asbestos moistened with 
 concentrated sulphuric acid, and in spite of their obvious 
 inconveniences these matches remained in use as late as 
 1844. The first friction match was made about 1806, and 
 contained phosphorus, but was not a practical success, and 
 it was not until 1827 that a satisfactory friction match was 
 produced. These were tipped with a mixture of potassium 
 chlorate and antimony sulphide, and were ignited by drawing 
 them sharply through a piece of glass paper held between 
 the finger and thumb. 
 
 The modern match industry is a large one, 17,250,000 
 gross boxes, each containing on the average 60 matches, 
 being manufactured in Great Britain in 1910, and this figure 
 only representing about half the consumption, a similar 
 amount being imported. In the United States the con- 
 sumption is about 250,000,000,000 matches per annum, 
 corresponding to about nine matches per day per head of 
 population, a figure corresponding closely with the con- 
 sumption per capitum in this country. 
 
MATCHES AND PYROTECHNY 163 
 
 Broadly, matches can be divided into two divisions, viz. 
 non-safety, or strike- anywhere matches, and safety matches 
 which are supposed to ignite only when rubbed on a prepared 
 surface, but which, as a matter of fact, can usually be ignited 
 by drawing them smartly across any smooth surface of low 
 heat conductivity, such as a sheet of glass or paper. 
 
 Composition for match heads is made up of five parts, viz. . 
 (i) oxidizable matter, (2) oxidizing agents, (3) inert gritty 
 matter (to increase friction), (4) colouring matter, and (5) 
 binding material. Striking surface for safety matches is 
 usually composed of inflammable matter only, with or 
 without the addition of grit to increase friction. 
 
 As oxidizable matter, yellow phosphorus was originally 
 used, but owing to its poisonous properties causing necrosis 
 (" phosy-jaw ") among the workers its use is now prohibited 
 in almost all countries. It has been replaced by sulphide 
 of phosphorus, sulphide of antimony, zinc sulphide and 
 scarlet phosphorus, or a mixture of two or more of these. 
 Sulphide of phosphorus, P 4 S 3 , is generally used for strike- 
 anywhere matches, although a very small proportion of this 
 type of match is made up with scarlet phosphorus, and the 
 use of lead, tin and copper thiocyanate has been proposed. 
 Sulphide of antimony, Sb 2 S 3 , is almost universally used for 
 safety matches. 
 
 As an oxidizing agent potassium chlorate enters into the 
 composition of almost all match heads, although potassium 
 bichromate, manganese dioxide and lead dioxide are also 
 used. 
 
 The inert gritty matter generally takes the form of 
 powdered glass, whereas pigments, such as ochre, ultra- 
 marine, etc., are used to improve the appearance. The 
 binding material is added in order to make the composition 
 adhere to the splint or taper, and is usually gum arabic or 
 dextrine. 
 
 As a striking surface, antimony sulphide and red phos- 
 phorus are usually made up with gum arabic or dextrine, and 
 then painted on to the sides of the box. 
 
 In the case of wax matches the flame from the head is 
 
164 EXPLOSIVES 
 
 sufficient to ignite the taper, but with wooden matches the 
 splint must be tipped with some inflammable material in 
 order to convey the ignition from the head to the wood. 
 This is usually done by dipping the splint into molten 
 paraffin wax before putting on the head. In France, and 
 to a lesser extent in America, however, sulphur is frequently 
 used for this purpose. Such matches burn at first with a 
 blue flame, evolving sulphur dioxide and giving practically 
 no light, and have therefore been named " wait-a-minute 
 matches." 
 
 To prevent the splints glowing after the flame has been 
 extinguished most modern wooden matches are impregnated 
 with certain inorganic salts. For this purpose sodium 
 tungstate is one of the most effective salts, but it is some- 
 what expensive, so that sodium or ammonium phosphate is 
 generally used, although zinc sulphate, magnesium sulphate, 
 alum and phosphoric acid have also been employed. 
 
 Various kinds of timber are used for the splints of wooden 
 matches, such as pine, aspen, spruce, etc., and the same 
 applies to the wooden boxes in which the matches are 
 put up. 
 
 In making up match composition the ingredients are 
 ground separately in the dry state, and then mixed wet. As 
 a rule the oxidizable matter and part of the inert matter are 
 mixed together with part of the gum solution and, separately, 
 the oxidizing agent is mixed with the rest of the inert matter 
 and binding solution. The two mixtures thus obtained are 
 then mixed together to form the paste ready for use. By 
 adopting this procedure danger of fire is reduced to a 
 minimum, as the oxidizable matter and oxidizing agent 
 are not brought together until both are thoroughly 
 wet. 
 
 The actual tipping of the matches is a purely mechanical 
 operation, and great ingenuity has been shown in designing 
 machines for carrying out the operation with the minimum 
 amount of labour. These machines cannot be described 
 in detail in a book of this nature, but the following description 
 will give a general idea of the principle on which they act. 
 
MATCHES AND PYROTECHNY 165 
 
 When making square matches the splints are usually cut 
 out in a separate machine, but in the case of round or grooved 
 matches the splints are usually cut out by the same machine 
 that tips them. The taper for wax matches is, of course, 
 made separately and fed into the match-making machine 
 after being cut to the correct length. Otherwise the 
 operation of making wax matches is similar to that used for 
 wooden matches, except that, of course, they are neither im- 
 pregnated nor tipped with wax. In the match machine the 
 splints are fed from a hopper into grooves in the iron match 
 plates, the splints being made to enter the grooves end on. 
 These plates are attached to an endless chain, and the hopper 
 is so arranged that just after the splints have been wedged 
 into the plates the chain passes over a pulley, thus leaving 
 the matches with the free ends pointing downwards. The 
 plates carrying the splints next pass over a bath of the im- 
 pregnating solution so that the splints are immersed, and 
 then over a bath of molten paraffin so that the free ends dip 
 into the wax. This wax usually has a melting point of 
 39 C., but is maintained at a temperature of ioo-io5 C. 
 by means of a steam jacket. After receiving their coating 
 of wax the ends of the splints pass through a third bath 
 containing the match-head composition. This is made of a 
 suitable consistency, so that a fairly large ''blob" of it 
 adheres to the end of the splint, and this constitutes the head. 
 After passing this bath the chain is carried upwards to the 
 ceiling of the building, or, what is better, through the 
 ceiling into an upper chamber. Here it passes over a long 
 series of rollers in order to allow the head to dry, the drying 
 operation being assisted by hot air. The chain then returns 
 to a point near the hopper, where the finished matches are 
 unloaded from the plates, and mechanically packed into the 
 boxes, these boxes being then mechanically made up into the 
 familiar packets of one dozen boxes. These packets are 
 subsequently made up by hand into packets of one gross* 
 
 Modern match machines are of considerable size, the 
 endless chain being as much as 700 ft. long, and taking an 
 hour to make one circuit. Such a machine will turn out 
 
166 EXPLOSIVES 
 
 about 1000 gross boxes of matches in a single day, corre- 
 sponding to nearly 9,000,000 matches, and only requires 
 eight girls to look after it. 
 
 As regards the composition of match-head material, 
 various recipes are in use. The heads of the old white 
 phosphorus non-safety matches were composed of 
 
 White phosphorus . . . . 2*5 kg. *2 kg. 
 
 Lead dioxide . . . . 24 kg. 
 
 Ferric oxide . . . . '5 kg. 
 
 Glass . . . . . . 2*0 kg. 
 
 Glue . . . . . . . . 2'0 kg. 
 
 Dextrine . . . . . . 6 kg. 
 
 Water . . . . . . 4-5 litres 4 litres 
 
 but the use of white phosphorus is now prohibited, modern 
 strike-anywhere matches being made with sulphide of phos- 
 phorus, or, to a very minor extent, with scarlet phosphorus. 
 Examples of such compositions are 
 
 P 4 S 3 6 
 
 Scarlet Phosphorus . . 10 
 
 KC10 3 24 45 
 
 ZnS 6 
 
 Ochre 6 
 
 CaCO 3 2 
 
 CaSO 4 5 
 
 Glass . . . . . . 6 22 
 
 Glue 18 10 
 
 H 2 34 45 
 
 Of these the former is a French recipe, i kg. of the wet 
 composition being sufficient for about 100,000 matches. 
 Unfortunately all matches containing sulphide of phosphorus 
 are apt to deteriorate in moist air with the liberation of 
 sulphuretted hydrogen. This can be remedied to some 
 extent by varnishing the head with shellac or collodion, but 
 several proposals have been made for non-safety match- head 
 composition in which no sulphide of phosphorus is used. 
 The use of scarlet phosphorus, made by boiling white phos- 
 phorus with phosphorus tribromide, is mentioned above, but 
 has never come into general use, although matches made with 
 
MATCHES AND PYROTECHNY 167 
 
 it are on the market. In Germany thiophosphites, made by 
 heating a metallic sulphide such as ZnS, Sb 2 S 3 , or Cu 2 S with 
 red phosphorus in an atmosphere of carbon dioxide to 
 450 C., have been used, and good results are claimed with 
 the following mixture : 
 
 Zinc thiophosphite . . . . . . . . '30 
 
 KC1O 3 60 
 
 ZnO 5 
 
 CaS0 4 3 
 
 CaCO 3 5 
 
 Glass . . . . . . . . . . 10 
 
 Barium cupro thiosulphate, BaCuS 4 O 6 , obtained by 
 precipitating two molecules of sodium thiosulphate with 
 one molecule of cupric chloride and one molecule of barium 
 chloride, has also been employed, as by its use a strike- 
 anywhere match containing no phosphorus at all can TDC 
 prepared. The following composition is recommended : 
 
 BaCuS 4 O 6 13 
 
 KC10 3 58 
 
 CaSO 4 10 
 
 S 37 
 
 Iron filings . . . . . . . . 4*3 
 
 Gelatine n 
 
 Safety matches, as a rule, are made up with sulphide of 
 antimony, and are ignited by rubbing on a surface of sulphide 
 of antimony and red phosphorus. Numerous recipes for 
 composition are in use, but the following may be taken as 
 typical : 
 
 Head. Striking surface. 
 
 Sb 2 S 3 . . 24 Red Phosphorus i 
 
 KC10 3 .. 32 Sb 2 S 3 .. .. -25 
 
 K 2 Cr 2 O 7 . . 12 Carbon . . . . -50 
 
 PbO 2 . . 24 Dextrine . . -30 
 
 Glass . . 2 
 Gum arable 4 
 
 but the compositions used by different makers vary widely, 
 and sulphur, manganese dioxide and ferric oxide are frequently 
 added. 
 
i68 EXPLOSIVES 
 
 PYROPHORIC AU,OYS 
 
 One of the oldest methods of obtaining fire was by 
 striking a spark from flint and steel and using this to ignite 
 some inflammable material, such as tinder. The introduc- 
 tion of matches led to the abandonment of this tiresome and 
 clumsy process, but the discovery of pyrophoric alloys of 
 cerium in 1903 led to its revival, and the modern " flint and 
 steel " or " briquet/' to use the French term, of which there 
 seems to be no translation, became such a serious rival to 
 matches that heavy taxes were imposed on them by those 
 countries in which the match industry was a State monopoly, 
 or in which matches were taxed for revenue purposes. The 
 outbreak of war gave a further impetus to the pyrophoric 
 alloy industry, as the " briquet " was preferred to matches by 
 the troops owing to its lessened sensibility to damp and to the 
 fact that the small quantity of petrol required could always 
 be obtained from the mechanical transport. The " briquet " 
 also became increasingly popular with the civilian population 
 owing to the scarcity of matches. 
 
 Opinions differ as to the reason for the pyrophoric 
 nature of cerium alloys. The pure metals of the cerium 
 group are only slightly pyrophoric, although their tempera- 
 ture of ignition is low, and it has been suggested that the 
 pyrophoric nature of the alloys is due to the increased 
 hardness allowing finely divided dust to be projected into 
 the atmosphere and ignited partly by the heat generated by 
 the friction and partly by spontaneous combustion due to 
 the large surface exposed to the oxygen of the air. It seems 
 more probable, however, that the pyrophoric effect is due 
 to the formation of highly inflammable suboxides. 
 
 For the preparation of pyrophoric alloys it is not 
 necessary to use pure cerium, it being customary to make use 
 of the crude mixture of rare earths left over as a waste 
 product when the thorium is extracted from monazite sand 
 for making incandescent gas mantles. In order to reduce 
 this to the metallic state various methods have been proposed, 
 such as reduction with metallic calcium, but industrially 
 
MATCHES AND PYROTECHNY 169 
 
 the process is always carried out electrically. This can be 
 done by the electrolysis of the oxide in fuzed cerium fluoride, 
 and on the laboratory scale this procedure gives excellent 
 results. Unfortunately the melting-point of the fluoride is 
 very high, about 1000 C., so that it has not been found 
 possible to use this process on an industrial scale, and for 
 manufacturing purposes it is usual to electrolyze a mixture 
 of cerium chloride and chlorides of the alkali earth metals. 
 In order to obtain satisfactory results the cerium chloride 
 must be dry and free from oxide and oxychloride. As the 
 chloride is soluble in alcohol, whereas the oxide and 
 oxychloride are insoluble, separation can be effected by use 
 of this solvent, but it is found better to obtain the pure, dry 
 chloride by heating the crude chloride with sal-ammoniac. 
 
 The electrolysis is carried out in a graphite crucible with 
 an iron cathode, and considerable difficulty is met with 
 owing to the tendency of the metal to remain distributed 
 in the electrolyte in very finely divided particles, or in the 
 colloidal form. 
 
 Various proposals have been made for suitable electro- 
 lytes, some investigators recommending a mixture of two 
 molecules of cerium chloride and one molecule of calcium 
 chloride, while others claim good results with mixtures of 
 calcium chloride and fluoride and barium fluoride. For 
 example, it is stated that excellent results are obtained by 
 fuzing three parts of barium chloride and three parts of 
 calcium fluoride with eight parts of calcium chloride in an 
 electric furnace, and then adding ten parts of cerium fluoride. 
 
 The metal obtained by electrolysis is usually cast into 
 blocks weighing from two to twenty pounds, and contains 
 about 80 per cent, of cerium, the balance being chiefly other 
 rare earth metals, and in this state it is quite unsuited 
 for pyrophoric purposes. A satisfactory pyrophoric alloy 
 must be sufficiently hard to allow sparks to be struck with 
 ease without being too hard, and at the same time it must 
 be sufficiently tough not to crumble away. In order to 
 obtain these properties it is usual to alloy the crude cerium 
 metals with about 30 per cent, of iron, a little zinc being 
 
170 EXPLOSIVES 
 
 sometimes added to convey hardness, and sometimes a little 
 copper to make the alloy tougher. The alloying is carried 
 out by heating iron powder in a graphite crucible under a 
 layer of an easily fuzible salt. The cerium is then added 
 little by little when it melts and slowly dissolves the iron. 
 The fuzible salt is used, of course, to protect the alloy from 
 the action of the air, but in spite of this considerable loss 
 takes place through oxidation, so that a pound of cerium 
 does not give much more than a pound of alloy. When the 
 whole of the iron has been dissolved the melt is cast either 
 into a single block, which is afterwards cut up for sale, or 
 into thin rods. Auer metal No. 2 is made somewhat 
 differently, as the alloy is cast into a block and then 
 ground to a powder, and this then moulded and heated 
 until it sinters together. The object of this process is to 
 obtain a finished stick that is impregnated with the lower 
 oxides, and improved pyrophoric properties are claimed to 
 be obtained by this process. 
 
 PYROTBCHNY 
 
 The art of making fireworks is very ancient, the first 
 use of explosives being for pyrotechnic purposes. The 
 term " fireworks " includes two classes of goods, viz. (i) 
 appliances for producing illumination, either for display 
 purposes, e.g. Bengal fire, display rockets, Roman candles, 
 etc., or for military or life-saving purposes, e.g. " star " 
 shell, Holme's buoys, etc., or for purposes of signalling, 
 e.g. Verey stars, marine rockets ; and (2) appliances for pro- 
 ducing sound either for display, e.g. crackers, or for signal- 
 ling, e.g. fog signals, maroons, etc. The explosive or com- 
 bustible materials used in firework construction can be 
 divided into three broad groups, viz. slow burning mixtures 
 for producing illuminating effects, such as golden rain, 
 coloured fire, stars, etc., more rapidly burning mixtures 
 used as propellants, e.g. for rockets, Catherine wheels, etc., 
 and rapidly burning mixtures used for bursting charges for 
 rockets and for the production of sound. In some cases 
 
MATCHES AND PYROTECHNY 171 
 
 guncotton us used as a sound producer, but otherwise all 
 the combustible material, both fast and slow, used in pyro- 
 techny is of the gunpowder type, additions of metal filings 
 being made in order to produce sparks and barium, copper, 
 strontium, etc., salts being added in order to produce 
 colour effects. For display purposes chlorates are largely 
 used, as they give more brilliant effects than nitrates, 
 probably largely owing to the greater volatility of the chloride 
 produced during combustion, but the use of chlorates in 
 the presence of sulphur is prohibited in Great Britain. The 
 danger of chlorate-sulphur mixtures is largely due to the 
 fact that some of the sulphur becomes oxidized to sulphuric 
 acid, and this increases the rate of decomposition of the 
 mixture, the reaction thus becoming autocatalytic. 
 
 The basis of almost all pyrotechnic mixtures other than 
 coloured lights is " meal powder," a fine grain gunpowder 
 to which sulphur, nitre or charcoal, or two or all of these 
 are frequently added to reduce its rate of burning. 
 
 Fireworks are almost invariably put up in paper cases, 
 these being made by hand by pasting several layers of 
 paper together. Rockets, squibs, crackers, etc., are all 
 made by this means, and even the " shells " which are fired 
 from mortars and contain coloured stars are made of paper, 
 although they are sometimes as much as 2 ft. in diameter. 
 These shells are made by tearing strips of paper and pasting 
 them together inside a hemispherical mould, layer upon 
 layer, until the desired thickness, | in.-i in., is attained. The 
 hemisphere thus formed is then removed and dried, after 
 which the edge is trimmed in a lathe and a complete shell 
 formed by gluing two hemispheres together. The quality 
 of the paper used is of great importance, and various qualities 
 are used for different purposes. As a general rule, it should 
 be free from all loading with mineral matter, and should have 
 as great a mechanical strength as possible. 
 
 Coloured fire (Bengal fire) is the simplest form of 
 firework, and simply consists of a moderately fiercely 
 burning mixture containing suitable salts to impart colour 
 to the flame, strontium and calcium being used to produce 
 
172 EXPLOSIVES 
 
 red, barium or copper for green, etc. Many different 
 mixtures can be used, of which the following may be con- 
 sidered typical : 
 
 Red. Yellow. Green. Blue. 
 
 KC10 3 78 NaN0 3 70 Ba(NO 3 ) 2 66 KC1O 3 45 
 
 SrC0 3 15 S 20 Sugar 33 C 5 
 
 Shellac 7 Sb 2 S 3 7 Shellac i CuCO 3 10 
 
 Carbon 3 HgCl 35 
 
 Shellac 5 
 
 Stars are very similar in nature, but are contained in a 
 rocket or shell, and only liberated and ignited when the 
 rocket or shell has reached its maximum height. They 
 are of two types, viz. " naked " or " pumped " and " pill- 
 box." The former are composed of a mixture of carbon, 
 sulphur, meal powder and a nitrate to impart the desired 
 colour, the ingredients being mixed together with shellac, 
 and then either moulded into pellets or spread out and cut 
 up into cubes, after which the solvent is dried off and the 
 " stars " loaded direct into the rocket or shell. " Naked " 
 stars should only be employed in fireworks of the smallest 
 sizes, as they are very apt to crumble. In any case, to avoid 
 crumbling it is very important to use shellac or other binding 
 material which is completely soluble in the solvent used, 
 usually methylated spirit. As a rule no special device is 
 used for igniting naked stars, ignition being brought about 
 by the burster charge, and for this reason they are almost 
 invariably composed of nitrate, as such mixtures are more 
 readily ignited than chlorate mixtures, and in any case a 
 naked chlorate star in contact with meal powder cannot be 
 used, as it would mean having a chlorate in contact with 
 sulphur. Sometimes, however, the moulded pellets are made 
 with a perforation into which a piece of quick match is 
 inserted to assist their ignition. 
 
 " Pill-box " stars are much safer than " naked " stars, 
 and are put up in paper cases, ignition being brought about 
 by means of quick match. They are usually chlorate 
 mixtures, e.g. 
 
MATCHES AND PYROTECHNY 173 
 
 Red. Blue. 
 
 KC10 3 47 56 KC10 3 40 37 
 
 Sugar 21 23 Sugar 25 25 
 
 SrCO 3 22 10 Cu 2 S 15 
 
 HgCl ii Cu 6 
 
 HgCl 20 32 
 
 Green. Yellow. 
 
 KC10 3 26 KC10 3 59 
 
 Sugar 22 Na Oxalate 17 
 
 Ba(NO 3 ) 2 30 Shellac 24 
 HgCl " 22 
 
 Magnesium or aluminium powder is also sometimes 
 added in order to increase the brilliancy. 
 
 Floating Stars are very similar, but are attached to 
 a- parachute of silk or soft paper. They are made to burn 
 slowly, and frequently the pellets are made up of several 
 layers, each layer of a different composition, so that they 
 change colour as they burn. 
 
 Star Shell for military purposes is composed of barium 
 and potassium nitrate, magnesium powder, paraffin and 
 boiled linseed oil. The composition used by the British 
 Army is made up of 
 
 Ba(NO 3 ) 2 i Ib. ii oz. 
 
 KNO 3 i Ib. 2 oz. 
 
 Mg . . . . . . . . i Ib. 3 oz. 
 
 Paraffin . . . . . . . . 5 oz. 
 
 Boiled oil . . . . . . 3 per cent. 
 
 Whereas the magnesium light rocket is made up of 
 
 Ba(NO 3 ) 2 i Ib. 8oz. 
 
 KC1O 3 . . i Ib. 2 oz. 
 
 Mg . . . . . . . . i Ib. 8 oz. 
 
 Boiled oil . . . . . . . . 3 per cent. 
 
 the propellant charge being meal powder. 
 
 Squibs are paper cases with a small exploding charge at 
 one end, and above it a long layer of slow burning composition 
 composed of meal powder mixed with sulphur, or sulphur 
 
174 EXPLOSIVES 
 
 and charcoal. They are primed with a little gunpowder, 
 and when ignited burn fiercely and then explode when 
 the ignition spreads to the charge of gunpowder at the 
 end. 
 
 Catherine Wheels are long, narrow paper tubes filled 
 with a mixture of meal powder (2 parts) and potassium 
 nitrate (i part) and sulphur (i part), and then wrapped 
 round a circular wooden disc. When a pin is placed through 
 the centre of the disc to act as a spindle and one end of the 
 paper tube ignited, the escaping gas causes the wheel to 
 revolve. 
 
 Roman Candles are paper cases containing coloured 
 stars separated by layers of a rather fiercely burning com- 
 position of meal powder, nitre sulphur and charcoal, such 
 as 
 
 Meal powder . . . . 3 4 8 
 
 KN0 3 4 5 2 
 
 S i 4 2 
 
 C 213 
 
 This composition burns fiercely with a good display of 
 sparks, the stars being ejected by the gases. Naked stars 
 are generally used, and the composition must not be tightly 
 packed, as otherwise they may break or crumble. 
 
 Whistling Fireworks are paper tubes packed with a 
 mixture of three parts of potassium pier ate and two parts of 
 potassium nitrate. One end of the tube is left open and the 
 other is closed, the gas escaping from the open end causing 
 a loud whistling noise. They are usually used as a garniture 
 for rockets or shells. 
 
 Rockets consist of two parts, viz. the body containing 
 the propellant, and the head containing the garniture. 
 The body is a paper tube constricted at the lower end 
 either by squeezing and then tying with a ligature, or by 
 means of a clay plug. In order to fill the body a conical 
 mould is inserted through the constricted end, point upwards, 
 and the propellant charge then added little by little and well 
 malleted home. There is considerable skill required in 
 
MATCHES AND PYROTECHNY 175 
 
 doing this, as the packing must be quite even if good results 
 are to be obtained. When the propellant has been added 
 the top is closed with a perforated clay plug through which 
 a piece of quick match passes in order to fire the head, and 
 the conical mould then withdrawn. The head is another 
 paper case containing a burster charge of gunpowder and 
 garniture in the form of stars, floating stars or whistling 
 fireworks, and is glued on to the body. The stick is then 
 attached so that the rocket balances when supported about 
 one inch from the base. It is fired by applying fire to the 
 conical hole left in the base by the mould. The outrush of 
 gases causes the rocket to ascend, and when at its maximum 
 height the quick match causes the burster charge to explode, 
 thus liberating the garniture. Various compositions are 
 used for the propellant, such as the following : 
 
 Meal powder . . . . . . 2 i 3 
 
 KNO 3 4 20 16 
 
 C 2 12 8 
 
 S i 2 4 
 
 although iron filings are frequently added in order to pro- 
 duce a good train of sparks. 
 
 Life-saving Rockets are similar, except that they have, 
 of course, no garniture, and are used for carrying a rope from 
 shore to ships in distress. The propellant composition is 
 usually made up as follows : 
 
 KNO 3 7lbs. 
 
 C atlbs. 
 
 S 2lbs. 
 
 Sometimes a head is provided closely resembling the body, 
 so that when the original body is exhausted the rocket 
 obtains a fresh impulse due to the firing of the head. 
 
 Touch Paper is much used for igniting fireworks, and 
 is made by brushing paper, usually blue in colour, on one 
 side with a solution of potassium nitrate (half a pound to 
 the gallon) and then drying. Slow match for pyrotechnic 
 purposes is made by soaking blotting paper in lead nitrate 
 solution (2j Ibs. per gallon) and, after drying, pasting the 
 
176 EXPLOSIVES 
 
 sheets together, usually so as to give six thicknesses. Pyro- 
 technic quick match, on the other hand, is made by impreg- 
 nating lamp wick cotton with a smooth cream of hot starch 
 solution and meal powder, and then dusting it over with 
 dry powder. Where ordinary quick match is not sufficiently 
 rapid it is threaded through paper tubes, as the confinement 
 greatly increases its rate of combustion. Such tubes are 
 known as leaders, and are used when various parts of a 
 firework have to be ignited almost simultaneously. 
 
 Fog Signals for the use of lighthouses during fog are 
 usually composed of Tonite, i.e. guncotton pulp that has 
 been impregnated with potassium or barium nitrate, and then 
 compressed into pellets and dried. They are fired by means 
 of a detonator. 
 
 Photographic Flash Lights are required to give out 
 light rich in actinic rays, and for this reason magnesium 
 powder enters into the composition of most of them. The 
 original flash lights were very simple in construction, and 
 consisted of a little magnesium powder placed in the bowl 
 of a clay pipe, a piece of cotton wool soaked in spirit resting 
 lightly on the top of the bowl. The spirit was lighted and 
 the magnesium powder then blown into the flame by 
 blowing air through the stem of the pipe. At present it is 
 usual to use magnesium powder mixed with an oxidizing 
 agent such as potassium chlorate or per chlorate or barium 
 chlorate, this latter salt giving a safer mixture than potassium 
 chlorate. Attempts have also been made to utilize the fact 
 that the oxides of the rare earth metals give off a great deal 
 of light when incandescent (cf. incandescent gas mantles) 
 and flash powders composed of magnesium powder mixed 
 with thorium or zirconium nitrate have been placed on the 
 market. Barium peroxide has also been used as an oxidizing 
 agent, and collodion cotton is also employed to some extent 
 as an ingredient. 
 
 In modern flash lights it is customary to replace part of 
 the magnesium by the less expensive aluminium powder, 
 and good results have been claimed with the following 
 mixture : 
 
MATCHES AND PYROTECHNY 177 
 
 Al 50 
 
 Mg . . . . . . . . 100 
 
 Fe 2 O 3 30 
 
 CuC0 3 30 
 
 MgS0 4 .. ;. ..5 
 
 As will be seen, the oxygen is supplied by the ferric oxide, 
 so that this powder is closely akin to Thermit in nature. 
 The anhydrous magnesium sulphate is added as a deterrent 
 to prevent combustion becoming too rapid. 
 
 The Holme's Life-buoy is an ordinary life-buoy to which 
 is attached a can containing calcium phosphide, this can 
 being closed by a lightly soldered plug. When used this plug 
 is wrenched out and the buoy then thrown into the sea. The 
 water on coming into contact with the calcium phosphide 
 causes an evolution of the spontaneous inflammable phos- 
 phides of hydrogen, the flame of which is visible at night. 
 The charge is usually sufficient to burn about half an hour. 
 
 LITERATURE 
 
 MATCHES 
 
 Freitag, " Zundwarenfabrikation," Vienna, 1907. 
 
 Jettel, " Zunchvarenfabrikation," Berlin, 1897. See also articles in 
 Thorpe's " Dictionary of Applied Chemistry," vol. iii. and Dammer, 
 " Chemische Technologic der Neuzeit," vol. i. 
 
 The following patents will be found of interest : 
 
 D.R.P. 101,737 ; 105,061 ; 153,188 ; 157,424 ; 165,090 ; 197,865. Also 
 Z. ang., 1900, 976 ; 1906, 2080 ; B.> 35, 351 ; 36, 979, 4202. The last two 
 of these deal with scarlet phosphorus. 
 
 PYROPHORIC ALLOYS 
 
 H. Kellermann, " Die Cerimetalle u. ihre pyrophoren Legierungen," 
 Halle, 1912. 
 
 C. R. Bohm, " Die Verwendung der Seltenen Erden," Leipzig, 1913. 
 
 O. Dammer, " Chemische Technologic der Neuzeit," vol. i. 
 
 R. Ullmann, " Enzyklopadie der technischen Chemie," vol. ii. 
 
 The following patents and references will also be found of interest : 
 
 D.R.P. 154,807 ; 172,529 ; 263,301 ; 268,827. 
 
 Ghent. Ind., 1913, pp. 195, 235. 
 
 Annalen der Chemie, 320, 231 ; 331, i, 45 ; 355, 116. 
 
 PYROTECHNY 
 
 There seems to be no modern works dealing with Pyrotechny, but 
 A. Bujard, " Leitfaden der Pyrotechnik," Stuttgart, 1889, gives a fair idea 
 of the subject. An interesting article will also be found in Thorpe's 
 " Dictionary of Applied Chemistry," but it requires to be read with care, 
 as a large number of the compositions described are out of date and illegal. 
 
 See also the article on " Feuerwerkerei " in Ullmann's " Enzyklopadie 
 der technischen Chemie," vol. v. 
 
 T. 12 
 
SECTION VIII. EXPLOSIVE PROPERTIES 
 
 APART from analytical operations certain tests are applied 
 to explosives in order to determine their properties. These 
 tests may be roughly divided into two classes, viz. tests 
 to determine the nature of the explosive and tests to deter- 
 mine its stability. The former includes tests for power, 
 violence and velocity of detonation, pressure, heat and 
 temperature of explosion, and production of flame, whereas 
 the latter includes tests for chemical stability, of which the 
 Abel heat test is the most important, and tests for sensitive- 
 ness to heat and mechanical shock. In addition, propellants 
 are tested to determine the velocity of the projectile and the 
 pressure attained in the gun, and, of course, these tests must 
 be carried out with the type of arm for which the explosive 
 is intended. Explosives for use in coal mines are further 
 tested to determine their safety when fired in the presence 
 of fire damp and coal dust, and these tests, together with the 
 methods used for studying flame production, have already 
 been described in Section V. 
 
 TESTS FOR POWER 
 
 The power of an explosive is its capacity for doing useful 
 work, and must not be confused with violence or brisance, 
 this latter being rather the rate at which work is done, or 
 the shattering effect produced. It is impossible to measure 
 the power of an explosive in definite units such as foot- 
 pounds, but tests have been devised which allow the 
 relative power to be compared. Comparisons should, 
 however, only be made between explosives of a similar 
 nature, as the figures given for brisant and non-brisant 
 
EXPLOSIVE PROPERTIES 179 
 
 explosives are hardly comparable. Useful as these com- 
 parisons are, it should always be borne in mind that the best 
 test of an explosive is its behaviour under working con- 
 ditions, and it is practically impossible to imitate these. 
 There are three methods in general use for testing power, 
 viz. the Trauzl lead block test, the mortar test, and the 
 ballistic pendulum. Of these the Trauzl lead block is the 
 simplest, and is the most generally used on the Continent, 
 whereas the ballistic pendulum is the most elaborate and 
 probably the best. A ballistic pendulum, however, is an 
 expensive piece of apparatus, so that its use is practically 
 limited to the official testing of explosives for the British 
 Permitted L,ist or the United States L,ist of Permissible 
 Explosives. 
 
 Trauzl Lead Block. This test is based on the volume 
 of the cavity formed when a given weight of an explosive 
 is fired in a bore-hole made in a block of pure lead, and in 
 order to obtain comparable results the test must be carried 
 out under absolutely standard conditions. These conditions 
 have been defined by a committee appointed by the Inter- 
 national Congress of Applied Chemistry (V. Congress, 1903, 
 vol. ii. p. 256), and may be summarized as follows : 
 
 The blocks are circular in section, and are 20 cm. high 
 and 20 cm. in diameter. They are cast of pure, soft chemical 
 lead, the bore-hole, which is 125 mm. deep and 25 mm. in 
 diameter being situated in the centre and cast in by means 
 of a suitable mould. Before use the blocks are allowed to 
 stand for several days. The weight of the explosive used is 
 10 grams, and this is made up into a cartridge 25 mm. in 
 diameter by wrapping it in a piece of tinfoil 70 mm. wide, 
 the length of the long sides being 120 and 150 mm. The 
 foil is of such a thickness that I square metre weighs 
 80-100 grams. A No. 8 electric detonator is inserted into 
 the cartridge, and the cartridge then pressed to the bottom of 
 the hole with a wooden rod, the wires being kept central. 
 Tamping is then applied by filling the hole with sharp, dry 
 quartz sand, which is of such a degree of fineness that it 
 passes a sieve with 144 meshes per cm. 2 , the wires being 
 
i8o 
 
 EXPLOSIVES 
 
 35 mm. thick. The charge is then fired electrically, and 
 any residue left shaken and brushed out of the cavity. 
 The volume of water required to fill the cavity is then 
 determined, and the volume of the original bore-hole 
 deducted, the figure thus obtained being taken as a measure 
 of the power of the explosive. At least three tests should 
 be made, and the mean of the figures thus obtained com- 
 pared with the mean of three similar tests made with a 
 standard explosive of approximately the same velocity of 
 detonation. The test should be carried out at a tem- 
 perature of I5-20 C. The enlargement caused by a de- 
 tonator alone is sometimes determined in the same way, 
 
 FIG. 26. Trauzl Block 
 before Firing. 
 
 FIG. 27. Trauzl Block 
 after Firing. 
 
 and this value deducted, but as the test is only a comparative 
 one this is unnecessary provided the standard explosive is 
 fired with a detonator of the same strength. Figs. 26 and 
 27 show Trauzl blocks in section before and after firing. 
 
 The Trauzl block test is a convenient one, but suffers 
 from several uncertainties. In the first place, it fails with 
 non-detonating explosives, as the pressure is developed so 
 slowly that the tamping is blown out. In the second place, 
 it is affected by variations in the lead and in the sand used 
 for stemming, so that as large a number of blocks as possible 
 should be cast from one melt and a good stock of sand kept. 
 With aluminium explosives, and other explosives with a 
 
EXPLOSIVE PROPERTIES 181 
 
 very high temperature of explosion, high results are obtained 
 owing to erosion, whereas with explosives containing an 
 excess of oxygen the influence of the tinfoil wrapper comes 
 into play unless the standard explosive used also contains 
 a similar excess of oxygen. The weight of the wrapper is 
 about i gram, i.e. 10 per cent, of the weight of the explosive. 
 The following table gives a few characteristic results 
 obtained when explosives are fired in the lead block : 
 
 N.G. . . . . 540 cc. P.A. . . 297 cc. 
 
 B.G 530 cc. T.N.T. . . 254 cc. 
 
 Dynamite No. i . . 300 cc. Tetryl . . 375 cc. 
 
 65 N.G. ) 
 
 Gelignite ] 25 NaNO 3 > 420 cc. G.C. .. 290 cc. 
 18 W.M. j 
 
 Mortar. This is shown in Fig. 28, the test being carried 
 out by measuring the distance that the shot is thrown when 
 
 FIG. 28. Mortar. 
 
 10 grams of the explosive are fired. , The explosive is weighed 
 out in a wooden shell 30 mm. in external diameter and 60 mm. 
 deep, which is then inserted into the charge chamber. A 
 piece of safety fuze with a detonator at one end is passed 
 through the central hole in the shot, and the shot then placed 
 in position with the detonator pushed well down into the 
 explosive. The shot weighs 15 kilos, and should be a good 
 
i82 EXPLOSIVES 
 
 but not a tight fit in the gun. The gun is securely fixed 
 on a concrete foundation, and is usually set with its axis 
 at an elevation of 45. The distance that the projectile 
 is thrown is measured and compared with that obtained 
 with an equal weight of a standard explosive of the same 
 nature. The bore at the back of the gun is provided so that 
 when one end becomes worn out the gun can be turned. 
 
 The method is a Somewhat crude one, but gives more 
 constant results than one would expect, and is useful when 
 experimenting with new explosive mixtures. In order to 
 obtain reliable results at least three shots should be fired, 
 and it is advisable also to fire one or two clearing shots 
 first in order to free the gun from rust. When new the 
 projectiles are inclined to expand in diameter owing to the 
 shock of the explosions, and give unreliable results, but this 
 expansion ceases after a few shots have been fired. In 
 order to make a gas-tight joint the shot should be well lubri- 
 cated before being inserted. The following figures give an 
 idea of the average throw obtained with a few standard 
 explosives, a 15 kg. shot being used, and the gun being set 
 at an angle of 45 : 
 
 Blasting Gelatine 240 metres 
 
 Gelatine Dynamite . . . . 188 
 
 Gelignite 168 
 
 Dynamite No. i . . . . . . 132 ,, 
 
 The explosives on the British Permitted lyist give 
 throws usually varying between 80 and 120 metres. 
 
 In order to save the trouble of fetching the projectile 
 after each shot, the gun is sometimes mounted as a pendulum 
 and the shot fired into a sand bank a few feet away. In 
 this case the recoil is measured, the arrangement being very 
 similar to that of the ballistic pendulum described below. 
 
 The Ballistic Pendulum. This is the Official Test for 
 the power of coal mine explosives both in the United States 
 and in this country, and both pendulums will be described. 
 The test has the great advantage that a reasonable weight 
 of explosive is used, J Ib. in America and \ Ib. in this country, 
 
EXPLOSIVE PROPERTIES 183 
 
 and that it is fired in its original wrapper and hence all 
 wrapper influence is eliminated, or, rather, the wrapper 
 influence is much the same as it would be under working 
 conditions. 
 
 The pendulum at the U.S.A. testing station at Pittsburg 
 consists of a 12*2 in. U.S.A. Army mortar, weighing 31,600 
 Ibs. It is slung in a stirrup made of ij-in. machine steel 
 rod, the rods being 8g| in. long. It is suspended on nickel 
 steel knife edges working on nickel steel bed plates, the bed 
 plates resting on massive concrete pillars. The explosive 
 is loaded into a steel gun which runs on a 30-in. gauge track 
 and is tamped with one pound of clay, or two pounds when 
 slow burning non-detonating explosives such as gunpowder 
 are being tested. Before firing the gun is run up to the 
 mortar until exactly ^ in. away from it. 
 
 The charge of standard explosive is eight ounces of 40 per 
 cent. American Straight Dynamite of the composition 
 
 N.G 40 
 
 NaNO 3 44 
 
 W.M 15 
 
 CaCO 3 i 
 
 which gives a swing of 27-3*1 in. By means of trial and 
 failure the weight of the explosive that gives approximately 
 the same swing as this is then determined, and three shots 
 fired with this weight. The exact equivalent is then 
 calculated from the ratio 
 
 S, : S D = W f i 
 
 where S* = swing given by W Ib. of the explosive under test, 
 
 S D = swing given by J Ib. of the standard explosive. 
 The pendulum in use at the British testing station at 
 Rotherham is somewhat smaller. The pendulum itself is a 
 mortar weighing 5 tons and suspended by steel rods from 
 an overhead axle having roller bearings. The bore-hole of 
 the gun is 30 in. long and if in. diameter, and the gun is 
 placed 2 in. from the mortar. Two pounds of well-rammed 
 dry clay are used as stemming, and the charge of explosive 
 
184 
 
 EXPLOSIVES 
 
 used is four ounces. The swing given is read off and com- 
 pared with the swing given by four ounces of Gelignite 
 containing 60 per cent, of nitroglycerine, this swing being 
 3*27 in. The swings recorded by the most important 
 explosives on the Permitted lyist are given in Section V. 
 
 TESTS FOR VIOLENCE 
 
 By the violence or brisance of an explosive is meant the 
 shattering effect produced. This is rather an illusive 
 quantity and depends not only on the power but also on 
 the maximum pressure developed, this in turn depending 
 on the velocity of detonation. Proposals have been made to 
 calculate the brisance mathematically, Bichel giving the 
 formula |MV 2 where M is the mass of the gaseous products 
 
 and V the velocity of detonation. 
 These, and other similar expressions, 
 however, do not give a satisfactory 
 value, and attempts have been made 
 to determine the comparative bri- 
 sance experimentally. The results 
 obtained cannot be said to be very 
 satisfactory so far, but they do give 
 some idea of the relative brisance. 
 They are all based on the crusher 
 gauge principle and measure the 
 deformation of a cylinder of a soft 
 metal, such as copper or lead. The 
 best-known form of apparatus is 
 the brisance meter devised by Kast 
 and shown in section in Fig. 29. This consists of a 
 hollow steel cylinder resting on a heavy steel base. A 
 small copper cylinder is placed centrally on the base, and 
 on the top of this a heavy steel piston which is an accurate 
 fit in the steel cylinder. On the top of the piston is placed 
 a nickel steel plate 20 mm. thick and weighing 320 grams, 
 on which rest two 4 mm. lead discs. These lead discs are 
 renewed after each shot, and have the object of protecting 
 the steel plate. The explosive is fired on the top of them, 
 
 FIG. 29. Brisance Meter. 
 
EXPLOSIVE PROPERTIES 
 
 185 
 
 and the crushing of the copper cylinder taken as a measure 
 of its brisance. The figures obtained vary with the diameter 
 and length of the cartridges, and seem to be at a maximum 
 when the length of the cartridge is about four times its 
 diameter. As would be expected, they also vary with the 
 density of the explosive, this having a great effect on the 
 velocity of detonation. As the explosive is fired unconfined, 
 the test does not in any way represent the conditions 
 attained in practical blasting operations. The following 
 figures were obtained using 15 grams of the explosive in 
 the form of a cartridge 21 mm. in diameter : 
 
 Explosive. 
 
 Density. 
 
 Velocity of 
 detonation. 
 
 Brisance. 
 
 ( 
 
 1-42 
 
 . 
 
 3' 5 7 
 
 Tetryl J 
 
 i'53 
 
 7145 
 
 3'9I 
 
 
 1*59 
 
 7160 
 
 3*94 
 
 
 i'34 
 
 6l6o 
 
 2-81 
 
 Picric Acid 
 
 1-40 
 1*53 
 
 6700 
 7000 
 
 3'34 
 3'55 
 
 
 I -60 
 
 7100 
 
 3-88 
 
 
 i'34 
 
 594 
 
 2'8o 
 
 T.N.T 
 
 i'45 
 
 6400 
 
 2'93 
 
 
 1-50 
 
 6590 
 
 3-13 
 
 
 1-60 
 
 6680 
 
 3'I3 
 
 D.N.B 
 
 '93 
 
 
 
 r6i 
 
 /T.N.T. 30 .. .. / 
 \Pb(N0 3 ) 2 7o .. .. t 
 
 2-65 
 
 2'75 
 
 4600 
 4700 
 
 2-52 
 2-86 
 
 VELOCITY OF DETONATION 
 
 The velocity of detonation represents the speed at which 
 detonation spreads or travels throughout the mass of the 
 explosive when once initiated. It can be determined by 
 two methods, viz. by the absolute method, in which the 
 interval of time is actually measured, and by the compara- 
 tive method, in which the velocity of detonation of one ex- 
 plosive is measured relatively to the velocity of detonation 
 of another. 
 
 Owing to the high velocities attained, frequently 6000- 
 8000 metres per second, the absolute method resolves itself 
 into the problem of measuring very small intervals of time. 
 
i86 
 
 EXPLOSIVES 
 
 For example, if a train of cartridges of Blasting Gelatine 
 10 metres long is detonated at one end, the detonation has 
 reached the other end in about -0013 second. For accurately 
 measuring such very short intervals of time the best method 
 has been found to be a drum of known diameter rotating 
 at a known speed. From the speed of rotation and 
 diameter of the drum the linear velocity of any point on 
 the surface is readily calculated, and hence the time that 
 
 FIG. 30. Determination of Velocity of Detonation (Mettegang's Direct 
 
 Method). 
 
 has elapsed between the making of two marks can be deduced. 
 The Mettegang time recorder for the determination of 
 velocity of detonation is based on this principle and by its 
 use intervals of time down to i x io~ 7 seconds can be 
 measured. The arrangement of the apparatus is shown 
 diagrammatically in Fig. 30. Two thin wires are embedded 
 in the explosive under test at a suitable distance apart, 
 usually about 3-4 metres, each of these wires forming part 
 
EXPLOSIVE PROPERTIES 187 
 
 of the primary circuit of different induction coils. One 
 terminal of the secondary circuit of each of these coils is 
 connected with the axis of the drum, while the other terminal 
 is connected with a platinum point which nearly, but not 
 quite, touches the smoked surface of the drum. The drum 
 is rotated by an electric motor at such a speed that the linear 
 velocity of the surface is 100 metres per second, and the 
 explosive is then detonated. When the detonation reaches 
 the first wire it breaks the primary circuit in one of the coils, 
 and the current thereby induced in the secondary circuit 
 causes a spark to pass between the corresponding platinum 
 point and the drum, this spark leaving a mark on the smoked 
 surface. The same thing takes place when the detonation 
 reaches the second wire, and by measuring the distance 
 between the two marks the time taken for the detonation 
 to travel between the two wires is calculated. The distance 
 between the two marks on the drum is measured by a 
 travelling microscope with a vernier scale reading to -01 mm., 
 this corresponding to ixio" 7 seconds when the surface 
 velocity of the drum is 100 metres per second. By using 
 more wires, each wire being connected with a separate coil 
 and platinum point, measurements of the velocity of detona- 
 tion at different points in a long train of cartridges can be 
 determined, thus ascertaining in any given case whether the 
 velocity remains constant or whether it increases or 
 decreases. 
 
 A certain amount of time always elapses between the 
 breaking of the primary circuit and the passing of the spark 
 due to the induced current in the secondary circuit. In 
 order to eliminate error from this source by making the lag 
 the same in both cases, the strength of the current in both 
 primary circuits must be the same, the coils must be of 
 exactly similar construction and resistance, and the direction 
 of the flow of the current must be the same in both. 
 
 In the indirect method the velocity of detonation of the 
 explosive is measured in terms of the velocity of detonation 
 of another explosive, detonating fuze always being chosen for 
 purposes of comparison owing to its convenience and very 
 
i88 
 
 EXPLOSIVES 
 
 constant velocity, about 5000 metres per second. The 
 determination is a very simple one, the arrangement used 
 being shown in Fig. 31. Two detonators are inserted into 
 the cartridge under test at a measured distance apart, 
 10 cm. being sufficient. Bach detonator is connected to 
 one end of a length of detonating fuze, the centre of which 
 rests on a lead plate. A mark is made on the lead plate 
 corresponding with the middle of the length of fuze, and 
 the cartridge of explosive then fired by means of an electric 
 detonator inserted in one end. When the detonation reaches 
 the first detonator it detonates one end of the fuze, and when 
 it reaches the other detonator it detonates the other end of 
 
 -\ 
 
 FIG. 31. Determination of Velocity of Detonation (Indirect Method). 
 
 the fuze. These two waves of detonation travelling through 
 the fuze in opposite directions meet at a certain point, and 
 where this happens a mark is left on the lead plate. Ob- 
 viously the distance of this mark from the centre of the 
 fuze represents the start that the one wave of detonation 
 had over the other wave, and hence the velocity of detonation 
 of the explosive can be calculated in terms of the velocity of 
 detonation of the fuze. 
 
 The velocity of detonation is affected to some extent by 
 the diameter of the cartridge, and increases as the diameter 
 increases. It usually, however, reaches a limiting value 
 above which it remains constant however much the diameter 
 is increased. With pure nitroaromatic compounds maximum 
 
EXPLOSIVE PROPERTIES 189 
 
 velocity is reached at 10 mm., but with other explosives it is 
 somewhat more, usually about 30 mm., and in the case of 
 ammonium nitrate explosives is frequently over 50 mm. 
 The following figures serve to illustrate this point : 
 
 Diameter Velocity 
 Explosive. (mm.), (metres per sec.). 
 
 Pure cast T.N.T. . . . . 21 6700 
 
 = 1-58 75 6595 
 
 220 6675 
 
 300 6710 
 
 Aldorfit 
 
 AmNO 3 = 81 . . . . 
 
 T.N.T. = 17 . . . . 26 4430 
 
 Rye meal 2 . . . . 40 49^5 
 
 The strength of the detonator or primer has little or no 
 effect provided it is sufficiently strong, but very irregular 
 results are sometimes obtained at first, both abnormally 
 high and low. With most explosives the velocity of the 
 wave of detonation increases or decreases until its normal 
 value is reached and then remains constant, but insensitive 
 ammonium nitrate explosives behave in a somewhat different 
 way, the velocity gradually decreasing. This is probably 
 due to insensitiveness, as the effect is most marked when the 
 explosive is compressed to a high density, in which case 
 detonation is usually difficult to start. lowering the 
 temperature, on the other hand, has no effect, velocities 
 remaining constant even at the temperature of liquid air 
 (-180 C.). 
 
 The effect of compressing the explosive and thus raising 
 its density is very great, and experiments seem to demonstrate 
 that velocity of detonation is a linear function of density. 
 It is true that with Cheddite and some other explosives the 
 velocity falls if the density exceeds a certain figure, but this 
 is probably due to the difficulty in starting a satisfactory 
 wave of detonation owing to the diminished sensitiveness 
 of the explosive. Thus picric acid enclosed in paper 
 cartridges 20 mm. in diameter gave the following figures 
 when fired with a detonator consisting of *5 gram 
 
EXPLOSIVES 
 
 fulminate and a primer containing 25 grams of Dynamite 
 No. i 
 
 Density. Velocity. 
 
 '93 .......... 5035 
 
 I-3I .......... 6255 
 
 1-46 .......... 6988 
 
 I'67 .......... 7 2 77 
 
 17 1 .......... 5045 
 
 174 .......... Failed 
 
 By increasing the primer charge to 80 grams of Dynamite 
 picric acid gave the following figures : 
 
 Density. Velocity. 
 
 1-62 ......... . 737 
 
 17 2 .......... 749 
 
 173 .......... 7645 
 
 174 ........ 7645 
 
 showing that by increasing the initial shock the explosive 
 could still be detonated and that the velocity of detonation 
 continued to increase. 
 
 Very similar results were obtained with T.N.T. 
 
 Density. Detonator. Primer. Velocity. 
 
 84 '5 gram fulminate Nil 3822 
 
 91 4087 
 
 92 4*7 
 
 90 ,, 25 grms. Dynamite No. i 4170 
 
 91 4170 
 
 1-32 6 2i7 
 
 1-46 66 75 
 
 1-56 ,, 6880 
 
 i'59 7 56 
 
 i -60 7 J 4 
 
 1-605 Failed 
 
 1-61 80 grms. Dynamite No. i 6943 
 
 The last figure was obtained when the T.N.T. was con- 
 fined in a copper tube, whereas the others were obtained 
 when the explosive was confined in paper. 
 
EXPLOSIVE PROPERTIES 191 
 
 The influence of the degree of confinement is very slight 
 with sensitive explosives having a high velocity of detona- 
 tion, but with the insensitive explosives of the ammonium 
 nitrate class it is very considerable. Figures illustrating 
 this will be found on pages 194 and 195. 
 
 Nitroglycerine exhibits the peculiarity of having two 
 velocities of detonation, one about 1300-1500 metres per 
 second, and the other about 7000-9000 metres per second. 
 At which of these velocities the wave of detonation travels 
 depends a good deal on the diameter of the tube and on 
 the strength of the primer or detonator, the following results 
 having been recorded : 
 
 Detonator. 
 
 i '6 grams. 
 1-6 
 
 Primer. Diameter. 
 
 Velocity. 
 
 6 mm. (glass) 
 
 Failed 
 
 9 mm. (glass) 
 
 654 
 
 25 mm. (iron) 
 
 1441 and 7690 
 
 38 mm. (iron) 
 
 8527 
 
 
 
 1776 
 
 Detonating 38 mm. (iron) 
 
 7234 
 
 fuze 
 
 
 Interesting results of the same nature have been obtained 
 with various American Dynamites and gelatinized explosives. 
 These latter when fired with a detonator only have a velocity 
 of detonation of about 2300 metres per second and this figure 
 is scarcely altered by increasing or decreasing the amount of 
 nitroglycerine present. When fired with a primer of American 
 Straight Dynamite, however, the velocity is much greater 
 and increases with the percentage of nitroglycerine, being 
 about 5100 metres per second with a nitroglycerine content 
 of 40 per cent., 6600 metres with Gelignite containing 60 per 
 cent, of nitroglycerine, and 7000 metres with 75 per cent. 
 Gelatine Dynamite. With the Straight Dynamites, on the 
 other hand, the velocity of detonation increases regularly 
 with increasing nitroglycerine content, and is not affected 
 by the use of a primer, provided a detonator of suitable 
 strength is used. 
 
IQ2 
 
 EXPLOSIVES 
 
 AMERICAN DYNAMITES 
 
 
 
 Gelatines. 
 
 Per cent. N.G. 
 
 Straight Dynamites with 
 or without Primer. 
 
 
 
 
 
 
 Detonator only. 
 
 Detonator and Primer. 
 
 5 
 
 1294 
 
 
 
 _ 
 
 10 
 
 2103 
 
 
 
 
 
 15 
 
 395 
 
 
 
 
 
 20 
 
 3197 
 
 
 
 
 
 25 
 
 3296 
 
 . 
 
 
 
 30 
 
 4172 
 
 2484 
 
 
 
 35 
 
 4605 
 
 2278 
 
 
 
 40 
 
 4848 
 
 2230 
 
 5122 
 
 45 
 
 532 
 
 2279 
 
 5544 
 
 50 
 
 5348 
 
 2355 
 
 5862 
 
 60 
 
 5973 
 
 2104 
 
 6606 
 
 75 
 
 6265 
 
 2165 
 
 6999 
 
 With Ammonia Dynamite in which half the nitroglycerine 
 has been replaced by ammonium nitrate the velocity of 
 detonation increases from 2100 with the 10 per cent, grade 
 to about 4400 with the 45 per cent, grade and thereafter 
 falls, the 60 per cent, grade giving a velocity of 3000. These 
 explosives are not gelatinized, and the velocity is not 
 materially increased by the use of a primer. Obviously the 
 increase in velocity shown when passing from grade 10 to 
 grade 45 is due to the increasing nitroglycerine content, 
 whereas beyond 45 per cent, the ammonium nitrate content 
 becomes the predominating influence, ammonium nitrate 
 explosives always being slow. 
 
 The dual velocity of detonation exhibited by liquid 
 nitroglycerine and gelatinized explosives is probably to be 
 accounted for by their exhibiting dual elasticity, under a 
 light shock behaving as liquids and under a heavy shock 
 as solids. The velocity of sound depends on the modulus 
 of elasticity of the transmitting medium according to the 
 equation 
 
 where \L is Young's modulus and d the density, and 
 probably the velocity of detonation follows a similar law, 
 
EXPLOSIVE PROPERTIES 
 
 193 
 
 but no results seem to have been recorded in which the 
 modulus has been determined. Certainly the velocity of 
 detonation increases with the density instead of decreasing, 
 but no conclusions can be drawn from this fact until the 
 effect of increasing density on elasticity has been studied ; 
 for if the modulus increases more rapidly than the density, 
 then the velocity of detonation would also increase if it 
 followed the above equation. The following table gives the 
 velocity of detonation in metres per second of a few well- 
 known explosives, where irregular results have been obtained, 
 the mean of the most concordant figures being given : 
 
 Explosive. 
 
 Density. 
 
 Velocity. 
 
 Remarks. 
 
 Mercury Fulminate 
 Detonating fuze . . 
 
 
 
 3920 
 5000-6000 
 
 6-45 mm. diam. 
 Phlegmatized fulmin- 
 
 
 
 
 ate. 
 
 
 1*5 
 
 4800-5000 
 
 T.N.T. 4-4 mm. diam. 
 
 Guncotton, dry . . 
 
 '9 
 
 3900 
 
 
 
 ,, 
 
 
 '2 
 
 4300 
 
 
 
 ,, . . 
 
 
 '4 
 
 4800-6200 
 
 
 
 wet (15 per\ 
 cent. H 2 0)J 
 
 
 
 
 5500-5800 
 
 23 mm. diam. 
 
 Nitromannitol . . 
 
 
 *5 
 
 7000 
 
 4 
 
 
 
 . 
 
 
 '9 
 
 7700 
 
 
 
 
 Nitroglycerine 
 
 
 
 
 1440 and 7690 
 
 25 
 
 
 
 Tetryl 
 Picric acid 
 
 i'5 
 
 34 
 
 7200 
 6160 
 
 21 
 
 
 
 ,, 
 
 
 46 
 
 6700 
 
 
 
 
 
 
 
 '53 
 
 7000 
 
 
 
 
 
 
 60 
 
 7100 
 
 
 
 
 Trinitrochlorbenzole 
 
 
 66 
 
 6800 
 
 
 
 
 Hexanitrodiphenylamine 
 
 i'5 
 
 8-1-67 
 
 7125 
 
 
 
 
 Trinitrocresol 
 
 
 52 
 
 6620 
 
 
 
 
 . 
 
 
 62 
 
 6850 
 
 
 
 
 Trinitro benzole (1.3.5) 
 
 
 63 
 
 6850 
 
 
 
 
 Trinitrotoluol (2.4.6) . . 
 
 
 '34 
 
 594 
 
 
 
 
 
 
 '45 
 
 6400 
 
 
 
 
 p 
 
 
 '5 
 
 6590 
 
 
 
 
 
 
 60 
 
 6680 
 
 
 
 
 Dinitrobenzole (1-3) 
 
 
 '5 
 
 6000 
 
 
 
 
 Macaritej^;; 
 
 2'73 
 2-89 
 
 4695 
 4860 
 
 
 
 
 e ^ 6 3 3 7 } compressed ' ' 
 
 1-58 
 
 6965 
 
 7155* 
 
 T-N.T. 90| compressedt> 
 
 1-56 
 
 6725 
 
 ,, 6680* 
 
 a$:SH-. - 
 
 i-57 
 
 6565 
 
 6680* 
 
 * These figures refer to the velocity of detonation of the chief con- 
 stituent of the mixture at the same density. 
 
 T. 13 
 
194 
 
 EXPLOSIVES 
 
 Explosive. 
 
 Density. 
 
 Velocity. 
 
 Remarks. 
 
 
 j^ XT V \ compressed . . 
 
 i-53 
 
 6280 
 
 21 mm. diam. 
 
 6660* 
 
 T.N.T. 50! 
 
 
 ( 1480 
 
 \ 
 
 
 D.N.T. 5oj cast " 
 
 I '5 I 
 
 "((Incomplete) 
 
 } " " 
 
 
 T.N.T. 5o\ 
 
 
 / 1910 
 
 
 
 D.N.T. 50) c ' ' 
 
 J *53 
 
 \ (Incomplete) 
 
 " 
 
 
 T N.T. 99'5) A 
 
 ( '3 
 
 Failed 
 
 26 ,, 
 
 
 Soft wax .2j com P r 
 
 I '33 
 
 5515 
 
 ,, 
 
 5920* 
 
 Dynamite No. i^ ? 5 5 
 
 63 
 
 1990 
 2560 
 
 20 ,, 
 
 
 M 
 
 '34 
 
 3670 
 
 ,, ,, 
 
 
 99 
 
 *54 
 
 5230 
 
 
 
 
 It 
 
 62 
 
 6800 
 
 ,, 
 
 
 Blasting Gelatine^ ~J$* 1-63 
 
 7700 
 
 30 .. 
 
 fN.G. 62 
 
 
 
 Gelignite! ^0,27 !' ! 1-67 
 
 2055 
 7000 
 
 26 
 
 3 > 
 
 I W.M. 8 
 
 
 
 N.G. 50.. ! 
 
 
 
 Dynamite, KNO^ri 
 5 opercent. WM 3 9 . ? 
 
 1-56 
 
 4610 
 
 26 , 
 
 CaCO 3 '2 
 
 
 
 
 !N.G. 40 . . 
 
 
 
 
 NaNO 3 42 
 W.M. 16-7 
 
 1-56 
 
 444 
 
 i > 
 
 CaCO 3 1-2 
 
 
 
 
 !N.G. 35 .'. 
 
 
 
 
 C.C. -3 -. 
 
 
 
 
 Ba(NO 3 ) 2 4 i 1-13 
 
 3970 
 
 
 
 KNO 3 25'5 1-20 
 
 4070 
 
 
 
 Tan meal 34*8 
 
 
 
 
 Na a C<V 5 .. 
 
 
 
 
 rN.G. 30 
 
 
 
 
 Carbonite]NaNO 3 24-5 . . 
 
 
 3720 
 
 
 
 No. II. J Flour 40-5 .. 
 
 I'lO 
 
 3850 
 
 ,, ,, 
 
 lK 2 Cr 2 7 5 .- 
 
 
 
 
 
 IN.G. 30 . . 
 
 
 
 
 Flo'u? 1 ' ' 
 
 
 
 - 
 
 W.M. 6 !'. 
 
 ri6 
 
 3900 
 
 
 
 Naphthalene * 
 
 
 
 
 Alum i 
 
 
 
 
 N.G. 3*8 
 
 
 
 
 C.C. "2 
 
 89 
 
 3700 
 
 26mm.diam.confined. 
 
 Donarite AmNO 8 80 . . 
 
 1-31 
 
 4140 
 
 3 
 
 T.N.T. 12 
 
 1-31 
 
 393 
 
 ,, unconfined. 
 
 Flour 4 
 
 
 
 rN.G. 4 .. ro6 
 
 3385 
 
 40 mm. diam. 
 
 Ammon- lAmNO 3 82 1-23 
 Carbonite] KNO 3 10 .. 1-19 
 
 3315 
 1650 
 
 26 
 30 ,, unconfined. 
 
 (Flour 4 . . j 1*19 
 
 3100 
 
 30 ,, confined, 
 
 * These figures refer to the velocity of detonation of the chief con 
 stituent of the mixture at the same density. 
 
EXPLOSIVE PROPERTIES 
 
 195 
 
 Explosive. 
 
 Density. 
 
 Velocity. 
 
 Remarks. 
 
 Aldorfit! 
 
 AmNO 3 81 
 T.N.T. 17 
 Rye flour 2 
 
 I'l 
 
 14 
 16 
 
 4825 
 4410 
 
 4925 
 
 40 mm. diam. confined. 
 26 
 
 4 
 
 I 
 
 
 17 
 
 4960 
 
 5 
 
 
 
 AmNO 3 66 . . 
 
 10 
 
 394 
 
 26 
 
 
 Gesteins 
 Dorfit 
 
 T.N.T. 15 
 KN0 3 5 
 
 ii 
 
 4420 
 4045 
 
 40 
 26 
 
 
 
 NaCl 10 
 
 15 
 
 455 
 
 4 
 
 
 
 Rye flour 5 
 
 
 4605 
 
 50 
 
 
 (AmN0 8 92.. 
 Thunderite{T.N.T. 4 . . 
 ( Flour 4 
 
 3650 
 2137 
 
 30 
 3<> 
 
 n 
 
 unconfined. 
 
 
 /AmNOo 42-5 
 
 
 
 
 T.N.T. 10 . . 
 Permonite KC1O 4 32-5 
 Starch 12 
 
 1-05 
 1-13 
 
 3690 
 3780 
 
 4 
 
 mm. diam. 
 
 
 W.M. 3 
 
 
 
 
 
 AmNO, 44-9 
 
 
 
 
 Ammonal (T.N.T. 31" .. ; i'68 
 
 4850 
 
 21 
 
 " 
 
 The velocity of detonation of Cheddite was given on page no. 
 
 PRESSURE OF EXPLOSION 
 
 The exceedingly high pressures attained during ex- 
 plosion render exact measurement a matter of considerable 
 difficulty. The first real instrument devised to estimate 
 these pressures was the Rodman gauge, in which the pressure 
 drove a hardened steel knife edge into a soft copper disc, 
 the penetration being taken as a measure of pressure 
 attained. The design of this gauge was afterwards improved 
 by Nobel, who used a copper cylinder placed between a 
 fixed and a movable steel piston. The pressure of the 
 gases acting on the base of the movable piston crushed the 
 copper cylinder, from the deformation of which the pressure 
 could be deduced. This type of gauge is known from its 
 mode of action as the crusher gauge, and is the standard 
 method of measuring the maximum pressure developed by 
 propellants in firearms. When used for this purpose the 
 gauge is either screwed into a hole bored in the explosion 
 chamber, or it is inserted behind the cartridge, so that the 
 base of the cartridge is in contact with the movable piston. 
 
ig6 EXPLOSIVES 
 
 This latter point is important, as otherwise the momentum 
 of the cartridge would cause abnormally high results. For 
 the same reason the movable piston must be closely in 
 contact with the copper cylinder, and when the gauge is 
 screwed into the firearm the end of the piston on which 
 the gases act, or the gas check which is usually placed in 
 front of the piston, should be flush with the end of the 
 cylinder in which the piston moves. Otherwise the momen- 
 tum of the gases will cause abnormal crushing. 
 
 For use with rifled arms in which the maximum pressure 
 attained is about 15 tons per square inch copper crushers 
 are always used, but with shot guns in which much lower 
 pressures, viz. about 3 tons per square inch, are developed, 
 lead cylinders are frequently employed. The use of the 
 crusher gauge is not, of course, confined to the study of 
 propellants, but can be used for the study of blasting 
 explosives when fired in bombs. It has the advantage of 
 being inexpensive and convenient, but unfortunately its 
 use is limited to the measurement of the maximum pressure 
 attained, and it gives no information as to the rate of 
 growth of this pressure. 
 
 Owing to the extremely rapid rate at which the pressure 
 rises during explosion, records showing its growth are 
 difficult to obtain, and although one or two instruments 
 have been devised for the purpose their use is limited, and 
 too much reliance must not be placed on the results obtained 
 with them. One of the most satisfactory is the Bichel 
 recorder. This consists of a massive steel cylinder, the 
 internal dimensions of which are 20 cm. in diameter and 
 48 cm. deep, the capacity thus being 15 litres. Charges 
 of 100-200 grams are fired, and the pressure attained 
 recorded on a rapidly revolving drum by means of a piston 
 acting against a powerful spring. The shape of the curve 
 gives a qualitative idea of the rate of development of 
 pressure, but the maximum is very much exaggerated 
 owing to the momentum of the moving parts. By neglect- 
 ing this peak value and extending the curve backwards 
 by extrapolation until it cuts the ordinate corresponding 
 
EXPLOSIVE PROPERTIES 197 
 
 to the moment of explosion a more nearly true value for 
 the maximum pressure can be read. 
 
 Owing to the low density of loading the cooling influence 
 of the walls is very great, and Bichel has sought to eliminate 
 this by using two bombs, one of 20 litres capacity and one 
 of 15 litres capacity. By means of inserting metal cylinders 
 of different sizes into the larger of these he was able to 
 obtain surfaces of 3600, 6600, and 7600 cm. 2 , while retaining 
 the same volume of 15 litres. 
 
 On firing charges under these three conditions he ob- 
 tained maximum pressure values which when plotted out 
 against the area were found to lie on a straight line. By 
 extending this line to the point area= o the pressure with 
 the surface eliminated could be read off. More recently 
 Peteval has introduced an improved recording manometer 
 in which a very stiff spring is used, and consequently only 
 a very slight movement of the piston takes place, this being 
 magnified by means of a mirror throwing a spot of light 
 on to a rapidly moving strip of sensitized paper. This 
 recorder has been used for the study of propellants, but not 
 for high explosives. 
 
 HKAT OF EXPLOSION 
 
 For determining the heat liberated on explosion appara- 
 tus similar to that used in ordinary calorimetric work is 
 used, but with suitable modifications to enable it to with- 
 stand the high pressures attained. Two types of bombs are 
 in general use, viz. the comparatively small bomb, the walls 
 of which are very thick to enable it to withstand the high 
 pressures developed, and the large bomb calorimeter in which 
 the increased volume results in lower maximum pressures, 
 and consequently less mechanical strength being called 
 for. Berthelot and Sarrau both used small, light bombs 
 which could only deal with a few grams of explosive owing 
 to their lack of mechanical strength, and Nobel and Abel 
 used bombs of about 32 and 119 c.c. capacity, these taking 
 charges of 12 and 26 grams of black powder respectively. 
 Nobel, however, also used a very heavy bomb in which as 
 
198 EXPLOSIVES 
 
 much as 500 grams of black powder could be exploded, 
 although the capacity of the bomb was less than half a 
 litre. It is very difficult, however, to construct bombs of 
 this type suitable for dealing with large charges of modern 
 high explosives, although a nickel steel bomb of 45 c.c. 
 capacity taking a charge of about 20 grams has been used 
 at the Neubabelsberg testing station, and is said to give 
 satisfactory results. 
 
 In determining the heat of explosion it is advisable to 
 use large quantities of the explosive in order to reduce the 
 error due to the rather uncertain correction which has to 
 be applied to eliminate the influence of the detonator. The 
 uncertainty of this correction is due to the fact that the 
 heat liberated by a detonator depends on whether it is 
 fired in an atmosphere rich in oxygen or not. If oxygen 
 is present not only is the carbon monoxide liberated by the 
 fulminate burnt to carbon dioxide, but the copper of the 
 detonator case is oxidized to cupric oxide, and heat is also 
 liberated by the combustion of the electric wires, etc., the 
 detonator always being fired electrically. Thus it has 
 been found that a No. 3 detonator fired in the absence of 
 oxygen liberates only *ii6 Cal. whereas in an oxidizing 
 atmosphere it liberates 791 Cal., and the amounts are of 
 course greater with larger sizes. In order to obtain a 
 bomb which has sufficient mechanical strength to withstand 
 the explosion pressure of large quantities of high explosive 
 without undue thickness of wall, the capacity must be 
 increased. This has been done by Bichel and Mettegang, 
 who have constructed a bottle-shaped steel bomb with a 
 capacity of 30 litres. Its walls are about 13 mm. thick, 
 and it weighs some 70 kilos. The usual charge of high 
 explosive used is 100 grams, but in the case of black powder 
 more than double this amount can be used with safety. 
 All the usual precautions of calorimetry are applied, and a 
 thermometer reading to '001 C. is employed for observing 
 the rise in temperature, as on account of the large heat 
 capacity of the metal the rise in temperature of the sur- 
 rounding water is only about i C. 
 
EXPLOSIVE PROPERTIES 
 
 199 
 
 The figures thus obtained give the heat evolved when 
 the explosive is detonated and the gases cooled to the. 
 ordinary temperature, and therefore include the heat 
 evolved by secondary reactions, such as the condensation 
 of the greater part of the water vapour produced, and the 
 heat evolved by the oxides of the alkali or alkali earth 
 metals combining with part of the carbon dioxide produced 
 to form bicarbonates. Hence, in order to obtain the heat 
 that would be actually evolved under practical working 
 conditions corrections must be applied. The following 
 figures give the heat liberated by the explosion of a few 
 well-known explosives. The figures refer to major calories 
 per kilogram of explosive : 
 
 Name. Composition. Heat liberated. 
 
 .TV- 
 Dynamite No. i 
 
 Blasting Gelatine 
 
 Gelignite 
 
 Donarite 
 
 Thunderite 
 
 Carbonite 
 
 Gunpowder . . 
 
 Nitroglycerine 
 Ammonium nitrate 
 Mercury Fulminate 
 
 rN.G. 
 
 75 ) 
 
 IGuhr 
 
 25 ' 
 
 (N.G. 
 *C.C. 
 
 92 \ 
 8 / 
 
 /N.G. 
 IC.C. 
 
 6 *'5\ 
 
 \NaNO 3 
 
 IW.M. 
 
 27-0 / 
 8-oj 
 
 /N.G. 
 
 Q *O\ 
 
 C.C. 
 T.N.T. 
 
 I2'0\ 
 
 AmNOg 
 
 80*0 
 
 \Flour 
 
 4*O 
 
 T.N.T. 
 
 4 
 
 AmNOg 
 
 92 
 
 Flour 
 
 4 
 
 N.G. 
 
 25 ' 
 
 KNOg 
 
 30-5 
 
 \ 
 
 Ba(N0 3 ) 2 
 W.M. 
 
 (KN0 3 
 C. 
 
 IS. 
 
 1422 
 
 1321 
 
 836 
 
 777 
 
 576 
 
 574 
 
 1471 
 
 365 
 407 
 
20o EXPLOSIVES 
 
 Calorimetric experiments can also be combined with 
 measurement of the volume of gas liberated. This can be 
 ascertained by direct measurement, but the large volumes 
 render this method troublesome. An alternative method 
 is to weigh the calorimeter before and after allowing the 
 gas to escape, and then calculating the volume from the 
 weight found together with the density. More usually, 
 however, the pressure is measured when the temperature 
 has become constant, and the volume at N.T.P. then calcu- 
 lated by the laws of Boyle and Charles. 
 
 TEMPERATURE OF EXPLOSION 
 
 Very little is known of the temperatures attained by 
 explosion, and no attempts seem to have been made to 
 measure them directly, although the difficulties of doing 
 so by means of an optical pyrometer should not be 
 insuperable, this method having been, in fact, used for 
 testing caps (see p. 152). It is theoretically possible to 
 calculate the temperature attained from a knowledge of 
 the total heat liberated and the specific heats and latent 
 heats of vaporization of the products of explosion. Un- 
 fortunately two factors militate against the accuracy of 
 such calculations. In the first place, nothing is known of 
 the equilibrium conditions from a chemico-dynamic point 
 of view of the products of combustion. It is fairly certain 
 that at the high temperatures reached both carbon dioxide 
 and water are to a large extent dissociated into their 
 elements 
 
 2C0 2 $ 2CO + 2 5> 2C + 20 2 
 
 and probably this dissociation to some extent goes a step 
 further, molecular oxygen and hydrogen breaking down 
 into the monatomic state. In all the above cases the high 
 pressure attained tends to force the equilibrium to the left 
 side of the equation, but nothing is known as to the com- 
 position of the equilibrium mixtures under the conditions 
 
EXPLOSIVE PROPERTIES 201 
 
 attained during or immediately after explosion, and the 
 same applies to other side reactions, such as the temporary 
 production of methane. These side or consecutive reactions 
 do not, of course, affect the total heat produced, but they 
 do affect the temperature attained by causing the explosive 
 reaction to take place over a greater time. In other words, 
 side and consecutive reactions produce a lower temperature, 
 but maintain this temperature for a greater time, the heat 
 evolved being the same as if the reaction had been a straight- 
 forward one taking place in one step. 
 
 In the second place, the specific heats of gases are not 
 even approximately constant quantities, but increase with 
 increasing temperature, and it is impossible to determine 
 them at the high temperatures attained during explosion, 
 especially as these temperatures are unknown. Mallard 
 and I,e Chatelier have investigated the matter, and have 
 deduced the following values (minor calories) for the 
 molecular heats at constant volume of gases at temperature 
 t C. : 
 
 Permanent gases, such as N 2 , O 2 , H 2 and CO 4*80 + -00062 
 Easily condensed gases, such as CO 2 and SO 2 6*26 + "0037^ 
 Water vapour 5-61 + '0033^ 
 
 and other investigators have obtained similar figures. To 
 what extent these figures are accurate it is difficult to say, 
 but it is improbable that their accuracy extends beyond 
 1500 C., whereas most temperatures of explosion are pro- 
 bably nearer 3000 C. The values of Mallard and L,e Chate- 
 lier have, however, been adopted by the French Government 
 for the calculation of the temperature of explosion of safety 
 coal mine explosives. The calculation is a somewhat 
 cumbersome one, but is quite straightforward, and as the 
 temperatures of explosion of explosives for use in coal 
 seams must not exceed 1500 C., or 1900 C. in the case of 
 explosives for use in rock in coal mines, the results are 
 probably more or less accurate, at all events, as far as the 
 former are concerned. 
 
202 EXPLOSIVES 
 
 CHRONOGRAPHY 
 
 In the case of propellants the velocity imparted to the 
 projectile by the explosive under conditions of use is a most 
 important point. The velocity of the projectile at various 
 points in its trajectory is of the utmost importance in 
 gunnery, but once the projectile has left the muzzle the 
 influence of the propellant ceases, so that from the explosive 
 manufacturer's point of view it is the mean muzzle velocity, 
 usually abbreviated to M.M.V., that matters. The name 
 ballistics is given to the study of the flight of projectiles, 
 internal ballistics dealing with their behaviour when in the 
 barrel, and external ballistics dealing with their flight from 
 muzzle to target. The subject of ballistics is highly mathe- 
 matical in nature, and no attempt will be made to treat it 
 beyond very briefly indicating the general principles on 
 which the experimental determination of velocity is 
 based. 
 
 Instruments for determining the velocity of a projectile 
 are known as chronographs, and, generally speaking, are of 
 two types, viz. those in which the time is measured in terms 
 of the time taken for something else to happen, e.g. in the 
 time taken for a weight falling freely to fall a certain distance, 
 and those in which the time is recorded directly. As the 
 muzzle velocity attained by projectiles from modern high 
 velocity rifled arms is usually from 2000 to 2500 ft. per 
 second, the time recorder must be capable of recording 
 small intervals of time. The passage of the projectile over 
 the space in which its velocity is being determined is indicated 
 by placing thin, brittle copper wires in its path, the projectile 
 severing these wires and thus breaking an electric circuit 
 so arranged that this interruption is recorded. 
 
 Le Boulenges Chronograph is shown diagrammatically 
 in Fig. 32. The fracture by the projectile of the first wire 
 breaks the circuit of the electro-magnet A, and allows the 
 weight B to fall. This weight is in the form of a tube 
 sliding freely over a vertical rod, so that it can fall freely 
 in an upright condition, but cannot topple over. To avoid 
 
EXPLOSIVE PROPERTIES 
 
 203 
 
 all chance of friction between the tube and the rod the latter 
 is sometimes omitted, but in this case it is difficult to be cer- 
 tain of the weight falling true. The fracture by the projectile 
 of the second wire breaks the circuit of the magnet C, and 
 allows the weight D to fall on to the button B. This latter 
 is connected with a trigger and spring arrangement, not 
 shown in the diagram, so that when 
 struck it releases the knife point F, 
 which, being actuated by the spring, 
 strikes the falling weight B, and 
 leaves a mark on its soft metal 
 covering. By holding C with this 
 mark in contact with F and then 
 measuring the distance between the 
 top of the weight and the bottom 
 of the electro-magnet A, the distance 
 which the weight has fallen can be 
 found, and from this the time cal- 
 culated. There are, however, several 
 sources of error in the figures thus 
 obtained, and these must be cor- 
 rected. In the first place, there is 
 the lag in the demagnetization 
 (hysteresis) of the two magnets, 
 which may or may not be the 
 same; and in the second place, 
 there is the time taken by the weight 
 D in reaching K and the time occupied by F in springing 
 forward. These errors are best allowed for by determining 
 a zero value, this being done by breaking the two circuits 
 simultaneously. When this is done the distance fallen by 
 B represents the magnitude of the lag due to electrical 
 and mechanical delays, and is to be allowed for when 
 calculating velocity. 
 
 This instrument is simple to use, and gives very fair 
 results over short distances, but when measuring a com- 
 paratively large interval of time the experimental error 
 becomes big. This is due to the fact that when a body 
 
 T E 
 
 FIG. 32. Le Boulenge 
 Chronograph. 
 
204 EXPLOSIVES 
 
 falls under constant acceleration, in this case the accelera- 
 tion due to gravity, the space traversed varies as the square 
 of the time 
 
 s = 
 
 or taking the value of / as 32 in foot-seconds units 
 
 So long as S is small, slight experimental error does not 
 affect t to any great extent, but when S becomes compara- 
 tively large experimental error affects t severely. 
 
 To overcome this difficulty Le Boulange devised an 
 instrument which he named the Klepsydra, and which was 
 based on the sand-glass principle. It consisted of a T- 
 shaped vessel rilled with mercury, the foot of the T being 
 provided with a needle valve. This was actuated elec- 
 trically, the breaking of the first wire opening the valve, 
 and the breaking of the second wire closing it. By weighing 
 the mercury which ran out in the interval the time during 
 which the valve was open could be deduced. Zero value 
 was obtained by breaking both ciicuits simultaneously. 
 
 The Bashforth Chronograph is based on a different 
 principle, the time being measured by the beat of a pendu- 
 lum. It consists of a revolving drum covered with smoked 
 paper and geared to a board in such a way that as the drum 
 revolves the board descends in a vertical direction. The 
 board carries two styles which are held away from the 
 surface of the smoked paper by means of electro-magnets. 
 The circuits of these magnets are broken in succession by 
 the projectile, thus allowing the styles to spring forward 
 and mark the smoked paper on the drum. By means of a 
 similar arrangement the pendulum makes time marks on 
 the paper so that the time that has elapsed between the 
 breaking of the two circuits is readily read off. 
 
 As inLe Boulange's instrument, electrical and mechanical 
 lag is corrected for by breaking the circuits simultaneously. 
 
 The Schultze-Marcel-Dieprez Chronograph is somewhat 
 similar in construction, the breaking of the circuits of 
 
EXPLOSIVE PROPERTIES 205 
 
 electro-magnets causing points to impinge on smoked paper 
 attached to a revolving drum. In this instrument, however, 
 time is marked simultaneously as a sinuous curve by means 
 of a tuning fork of definite note, a style being attached to 
 one prong and this style being in contact with the revolving 
 drum. The tuning-fork is one of the most convenient 
 methods of recording moderately short intervals of time, 
 and is widely used in all branches of physics. As a matter 
 of convenience the fork may be electrically controlled. 
 
 The Mahieu Chronograph is very similar to the above, 
 but the drum in addition to a rotatory movement has also 
 a longitudinal movement. The pens are in permanent 
 contact with the surface of the paper, but are attached to 
 springs so that they spring to one side when the circuits 
 of the electro- magnets are broken, thus causing a sudden 
 momentary change in direction in the line being traced. 
 The gearing controlling the relative longitudinal and rotatory 
 movement of the drum is capable of alteration so as to 
 render the instrument suitable for measuring high and low 
 velocities and of dealing with both short and long flights. 
 
 Of course, either the Bashforth, the Schultze or the 
 Mahieu instrument can be used for studying the velocity 
 of a projectile at different points of its flight, it being only 
 necessary to add more pens, but the Mahieu instrument is 
 best adapted for work of this nature. 
 
 LITERATURE 
 
 A good general description of the tests applied to Explosives \\ill be 
 found in U.S. Bureau of Mines, Technical Paper No. 186. 
 
 POWER 
 
 Conditions for the Trauzl lead block test are given in the " Report of 
 the Fifth International Congress of Applied Chemistry," 1903, vol. ii. p. 286. 
 
 See also C.r., 1907, 1032 ; S.S., 1907, p. 313 ; Z. ang., 1911, 2234. 
 
 The American ballistic pendulum is described in detail in Bulletin 
 of the U.S. Bureau of Mines, No. 15, p. 79, other tests being discussed 
 also. The British pendulum at Rotherham is described in A .R., 1912, 
 p. 83. 
 
 See also S.5., 1913, p. 265. " VIII. Congress of Applied Chemistry," 
 vol. 25, p. 209. 
 
 BRISANCE 
 
 Kast, " Spreng- u. Zund-stoffe," 1031. S.S., 1906, p. 151 ; 1913. P- 8 9- 
 
206 EXPLOSIVES 
 
 VELOCITY OF DETONATION 
 
 C. E. Bichel, " Testing Explosives," English translation by A. Larnsen, 
 London, 1905. 
 
 Kast, " Spreng- u. Zund-stoffe," 1025. 
 
 " V. Congress of Applied Chemistry," vol. ii. p. 327. 
 
 " VIII. Congress of Applied Chemistry," vol. iii. b, p. 28. 
 
 Bulletin of the U.S. Bureau of Mines, No. 15, p. 92. 
 
 C.Y., 143, 641. P.5., xvi. 27; xvii. 154. S.S., 1908, p. 403; 1913 
 pp. 65, 88, 90, 133, 155, 172. 
 
 PRESSURE 
 
 A. Nobel, " Artillery and Explosives," 
 C. E. Bichel, " Testing Explosives." 
 
 Phil. Trans., 1905, p. 357. 5.5., 1908, p. 366. 
 
 HEAT 
 
 C. E. Bichel, " Testing Explosives." 
 5.5., 1907, pp. 281, 306 ; 1908, p. 406. 
 Bulletin of U.S. Bureau of Mines, No. 15, p. in. 
 
 TEMPERATURE 
 C.v., 1881, 1014. 
 Z. el. ch., 1909, 536 ; 1910, 897. 
 S.S., 1907, p. 306 ; 1909, pp. 281, 305, 388 ; 1910, pp. 205, 248, 266, 
 
 291, 31. 376, 399, 452, 474- 
 
 Bulletin of U.S. Bureau of Mines, No. 15. 
 
 CHRONOGRAPHY AND BALLISTICS 
 
 F. Bashforth, " Experiments made with the Bashforth Chronograph," 
 Cambridge, 1890-1900. 
 
 B. Glatzel, " Elektrische Methoden der Momentanphotographie," 
 Brunswick, 1915. 
 
 J. M. Ingalls, " Interior Ballistics," New York, 1912. 
 P. Charbonniere, " Balistique Interieure," Paris, 1908. 
 
 C. Cranz, " Lehrbuch der Ballistik," 3 vols. Berlin, 1910-1913. 
 
 A. C. Crehore and G. O. Squier, " Polarizing Photo-Chronograph," 
 New York, 1897. 
 
 T. Kozak, " Einfuhrung in die aussere Ballistik," Vienna, 1911. 
 
 The photography of the air disturbance caused by a projectile is 
 described in 5.5., 1911, pp. 261, 330. 
 
SECTION IX. SENSITIVENESS AND 
 STABILITY 
 
 AN explosive must fulfil certain conditions as regards 
 sensitiveness and stability if it is to be suitable for com- 
 mercial use. Unless intended for use as an initiator in 
 percussion caps or detonators it should not be unduly 
 sensitive to mechanical shock, as if it is it will be unsafe 
 to handle and transport. At the same time it must be 
 moderately sensitive to detonation and should be exploded 
 fairly easily by influence, i.e. by the explosion of another 
 cartridge of the same explosive lying near it but not actually 
 in contact with it. A moderate degree of sensitiveness to 
 explosion by influence is very desirable, as in blasting 
 operations the bore-holes are usually charged with several 
 cartridges which may be separated from one another by 
 an air space due to defective ramming or by a layer of dust 
 that has fallen into the hole during charging. Only one 
 -cartridge carries a detonator, and hence if the explosive 
 is not readily exploded by influence some of the cartridges 
 may fail to detonate and may cause an accident by being 
 struck with a pick or shovel later on. 
 
 Stability is also highly desirable in an explosive intended 
 for practical use, as should chemical decomposition take 
 place during storage either the explosive may fail to detonate 
 owing to loss of explosive properties, e.g. mercury fulminate, 
 or it may become excessively sensitive or even explode 
 spontaneously, e.g. chlorate-sulphur mixtures. All organic 
 nitric esters have a tendency to decompose spontaneously at 
 the ordinary temperature with the production of nitric acid. 
 In most cases the reaction is an extremely slow one, but the 
 velocity is greatly increased by the catalytic effect of acids. 
 
208 EXPLOSIVES 
 
 Since acid is actually produced by the decomposition the 
 reaction is auto-catalytic, and hence it is of the utmost 
 importance to test all explosives to determine the relative 
 rate of production of acid. The Abel Heat Test is designed 
 for this purpose, and in spite of its numerous imperfections 
 gives a fair idea of stability. Chlorate-sulphur mixtures 
 become dangerous from a similar cause, as atmospheric 
 oxygen converts traces of the sulphur into sulphuric acid, 
 this in turn liberating the highly dangerous chloric acid. 
 
 In addition to chemical stability, physical stability is 
 also of importance. Thus most explosives containing nitro- 
 glycerine are liable to " sweat " or " exude " this substance, 
 and as nitroglycerine is very sensitive to shock, the sensitive- 
 ness of the explosive is greatly increased although no chemical 
 decomposition has taken place. Blasting gelatine is par- 
 ticularly liable to exude, exudation from Gelignite and 
 Gelatine Dynamite being hindered by the absorptive 
 properties of the wood meal used for doping these explosives. 
 Deliquescence is another example of what may be termed 
 physical stability. Explosives containing hygroscopic sub- 
 stances such as nitrate of ammonia take up moisture rapidly 
 and may become quite unfit for use in a short time. The 
 behaviour of an explosive when subjected to heat is also 
 important, as is its behaviour when ignited, it being pre- 
 ferable from a safety point of view that under these cir- 
 cumstances it should burn away quietly without exploding. 
 Finally, with powdered explosive mixtures degree of incor- 
 poration must be examined, as if not properly incorporated 
 the constituents may separate when submitted to vibration, 
 e.g. during transport, the explosive subsequently giving 
 irregular results. 
 
 MECHANICAL SHOCK 
 
 Mechanical shock may be of two types, viz. shock due 
 to friction or shock due to a direct blow. Comparative tests 
 to determine the relative sensitiveness to friction of two 
 explosives are difficult to carry out owing to the impossi- 
 bility of fixing a standard of friction, but a rough idea can 
 
SENSITIVENESS AND STABILITY 
 
 209 
 
 be obtained by various means such as grinding the samples 
 in a mortar under as similar conditions as possible, striking 
 them a glancing blow either by hand, or, better, by means 
 of a pendulum arrangement. 
 
 A direct blow is much more easily imitated, and the 
 falling weight test is invariably made use of. The apparatus 
 
 for this consists of an anvil surrounded ^ ^ 
 
 by a cylinder in which a piston works 
 freely in a vertical direction, but is 
 incapable of lateral movement. The 
 explosive is spread on the anvil and the 
 piston inserted into the cylinder so that 
 its lower end rests on the explosive. 
 The upper end of the piston is then 
 struck a blow by a definite weight falling 
 from a definite height, the height being 
 gradually increased until explosion takes 
 place. The falling weight slides freely 
 over vertical guide rods so as to assure 
 its falling true and striking a direct and 
 not a glancing blow. The apparatus is 
 shown in Fig. 33. 
 
 Theoretically the force of the blow is 
 given by the mass of the falling weight 
 multiplied by the velocity with which it 
 
 strikes, or 
 
 FIG. 33. Falling 
 
 F = M X V 2gS Or F = 8MV S Weight Test. 
 
 where M is the mass of the falling weight, S the height 
 through which it has fallen, and g the acceleration due to 
 gravity. In other words, the force of the blow should be 
 proportional to the product of the weight into the square 
 root of the height. In practice this is not the case, but the 
 test is not of sufficient accuracy to be susceptible to mathe- 
 matical treatment. For one thing, the results depend on 
 the thickness of the layer of the explosive, its physical 
 nature (density, size of grain, etc.), nature of the surfaces 
 with which it is in contact, temperature, etc. ; and hence, 
 T. 14 
 
210 EXPLOSIVES 
 
 in order to obtain comparable results, the measurements 
 must be made under strictly standard conditions. These 
 have been laid down by an International Committee as 
 follows : 
 
 The anvil and the piston are made of hardened steel, 
 the former resting on a firm foundation, and the area of 
 each is 127 mm. 2 (1*27 cm. in diameter). The weight 
 of explosive used is '05-' i, the amount being chosen so as 
 to give a layer of standard thickness when spread uniformly 
 on the anvil. The sample is dried over calcium chloride 
 before use, and a fresh quantity taken for each experiment. 
 The standard temperature is i8-20 C., and the weight used 
 weighs two kilograms. 
 
 Although these are the " Official " conditions they cannot 
 as yet be said to be generally adopted, and most data avail- 
 able have been obtained under somewhat different conditions. 
 The following results give a fair idea of the figures obtained, 
 and were given by Will at the VI. Congress of Applied 
 Chemistry. He used *i gram of explosive which had been 
 dried at 40 C., and which was confined between steel surfaces 
 and struck by a falling weight of 2 kilos. : 
 
 Mercury Fulminate . . . . . . 2 cm. 
 
 Nitroglycerine (dry) . . . . . . 4 
 
 I/ead picrate . . . . . . . . 5 ,, 
 
 Dinitroglycerine . . . . . . 7 
 
 Dynamite No. i . . . . 7 ,, 
 
 (frozen) 25 
 
 Blasting Gelatine . . . . . . 12 
 
 (frozen) .. .. 12-15 ,, 
 
 Gelatine Dynamite . . . . . . 17 
 
 Gunpowder (sporting) . . . . 70 
 
 (blasting) 85 
 
 Cheddite, Type 60 32 
 
 Type 41 36 ,, 
 
 Tetryl 40-65 ,, 
 
 Hexa-nitrodiphenylamine . . . . 40 
 
 T.N.T 57-i8o 
 
 Dinitrobenzene . . . . . . 120 ,, 
 
 Tri-nitronaphthalene 175 ,, 
 
SENSITIVENESS AND STABILITY 211 
 
 Ammonium picrate 
 Picric Acid 
 
 Guncotton (15 % H 2 O) . . 
 Collodion (15 % H 2 O) . . 
 Nitrocellulose propellants 
 
 Astralite 
 
 Donarite 
 
 Guncotton (20 % H 2 O) . . 
 
 Collodion (20 % 
 
 H 2 O) 
 
 . . 80 cm. 
 
 35-95 
 ..85 
 . . 100 ,, 
 
 30-54 .. 
 .. no 
 .. no 
 
 over 185 
 over 185 
 
 The following figures give a rough idea of the result of 
 using different weights, in all cases 'i gram of explosive 
 being used, and this being wrapped in tinfoil. The falls 
 are given in centimetres 
 
 Explosive. 
 
 Composition. 
 
 i Kg. 
 
 5 Kg. 
 
 I Kg. 
 
 2 Kg. 
 
 5 Kg. 
 
 Guncotton 
 
 Dry 
 
 30-40 
 
 5-10 
 
 5-10 
 
 5-10 
 
 _ 
 
 >i 
 
 15 % H 2 
 
 
 15-20 
 
 10-15 
 
 10-15 
 
 5-10 
 
 Picric Acid 
 
 Crystalline 
 
 . 
 
 
 
 190-200 
 
 IOO-IIO 
 
 50-60 
 
 M 
 
 Compressed 
 
 
 
 
 
 . 
 
 140-150 
 
 80-90 
 
 T.N.T. . . 
 
 Crystalline 
 
 . 
 
 
 
 180-190 
 
 90100 
 
 50-60 
 
 
 
 Compressed 
 
 - 
 
 
 
 
 
 150-160 
 
 80-90 
 
 
 N.G. 30 ) 
 
 
 
 
 
 
 Carbonite No. 2 
 
 NaN0 3 24-5 
 Flour 40-5 j 
 
 60-70 
 
 IO-2O 
 
 IO-2O 
 
 IO-2O 
 
 
 
 
 K 2 Cr 2 O 7 5-0 J 
 
 
 
 
 
 
 
 N.G. 3'8 
 
 
 
 
 
 
 
 C.C. '2 
 
 
 
 
 
 
 Donarite 
 
 AmNO 3 80-0 
 
 
 
 
 
 120-130 
 
 60-70 
 
 15-20 
 
 
 T.N.T. 12-0 
 
 
 
 
 
 
 
 Flour 4*0 
 
 
 
 
 
 
 
 
 
 
 
 
 
 The U.S. Bureau of Mines make use of a much larger 
 machine in which greater quantities of explosive (20 grams) 
 can be used. The falling weight weighs 200 kilos., and it is 
 claimed that the figures obtained are of greater value, as 
 actual practical conditions of use are more nearly imitated. 
 The results obtained with this machine are quite different 
 from those obtained by the smaller machines. 
 
 DETONATION 
 
 Sensitiveness to detonation depends largely on the 
 physical state of the explosive undergoing test, and almost 
 
212 EXPLOSIVES 
 
 invariably decreases with increasing density, at high 
 densities most explosives becoming so insensitive that they 
 either cannot be detonated at all or, if detonated, the detona- 
 tion is incomplete. At low temperatures sensitiveness is 
 also diminished, while at elevated temperatures, as would 
 be expected, the reverse is the case. 
 
 Ease of detonation is very simply determined by firing 
 cartridges of the explosive with detonators of different 
 power, and thus finding the weakest that will cause complete 
 detonation under the conditions of the experiment. In the 
 case of insensitive explosives that require a primer of some 
 more sensitive explosive in order to detonate them completely 
 the minimum weight of the primer is determined in the same 
 way. 
 
 INFLUENCE 
 
 The capacity of one cartridge of an explosive to detonate 
 another cartridge separated from it by an air space depends 
 on the sensitiveness of the explosive and on the velocity of 
 detonation, and hence also on the physical state of the 
 explosive. It also depends on the nature of the surface on 
 which the cartridges are resting, being at a minimum when 
 they are suspended so that the wave of detonation can only 
 be transmitted through the air, and at a maximum when the 
 cartridges are resting on some hard, solid substance such as 
 iron, in which case the wave of detonation is no doubt 
 largely transmitted through the solid body. The distance 
 through which detonation is transmitted is determined by 
 the method of trial and failure, cartridges being exploded at 
 increasing distances until the detonation is no longer trans- 
 mitted from one to another. The figures thus obtained 
 depend very much on the explosive, and vary from a small 
 fraction of an inch to several feet. They also depend largely 
 on the quantity of explosive involved, the explosion of large 
 amounts, as for example during an accident, being capable 
 of exploding other explosives at a considerable distance. 
 
 With reference to this experiments have been carried 
 out to determine the velocity with which the wave of 
 detonation is transmitted through air, This was done with 
 
SENSITIVENESS AND STABILITY 213 
 
 detonating fuze in much the same way that velocity of detona- 
 tion (page 187) is determined, two cartridges being separated 
 from, but hanging end on to one another, and detonators 
 inserted into the inner ends and connected by detonating 
 fuze. One of the cartridges was then fired by an independent 
 detonator, and the velocity of the wave of detonation through 
 the air space determined by the behaviour of the fuze. It 
 was found that the wave of detonation starts through the 
 air with about the same velocity as it has in the cartridge, 
 but that there is a retardation of about 50 metres per second 
 for every centimetre of air traversed. 
 
 HEAT AND IGNITION 
 
 The temperature at which an explosive ignites or explodes 
 depends on how rapidly the temperature is raised, and is not 
 a definite value like the melting-point of a pure chemical 
 compound. It is rather analogous to the melting-point of 
 a chemical compound in which decomposition sets in before 
 its melting-point is reached, so that if the heating takes 
 place slowly an indefinite value is obtained, whereas if 
 the heating is rapid a fairly definite point can be deter- 
 mined at which the compound melts before decomposition 
 has gone far enough to have much effect. Hence, in deter- 
 mining the ignition point of an explosive a preliminary 
 experiment should first be carried out in which the heating 
 is slow in order to determine an approximate value, and 
 then a more accurate measurement made in which the 
 apparatus is pre-heated to this point before the explosive 
 is introduced. By this means it has been found that nitro- 
 glycerine explodes at about 170 C. and nitrocellulose at 
 io-20 higher. 
 
 From the point of view of safety it is desirable that 
 an explosive should burn away quietly without ex- 
 ploding if accidentally ignited, but the behaviour of an 
 explosive under these circumstances depends largely on 
 how the ignition is started, the degree of confinement of the 
 explosive, and on the quantity. Hence laboratory results 
 are of comparatively little value, although more or less 
 
214 EXPLOSIVES 
 
 useful indications can be obtained by igniting small quantities 
 in various ways, such as by means of a match or a piece of 
 safety fuze, or by throwing some of the explosive into a hot 
 dish. As a rule, when in small quantity, nitroglycerine 
 explosives burn away fiercely, but do not explode, but with 
 larger quantities explosion generally takes place. Ex- 
 plosives containing chiefly ammonium nitrate and small 
 quantities of nitroaromatic compounds, on the other hand, 
 are almost incombustible, but large quantities submitted 
 to a high temperature may explode. 
 
 INCORPORATION 
 
 Black powder and other explosives containing only solid 
 constituents, such as ammonium nitrate explosives, if not 
 sufficiently incorporated, may settle out when submitted to 
 vibration during transport, and thereafter either do not 
 explode at all or give very irregular results. To ascertain 
 if the incorporation is satisfactory a sample of the explosive 
 is submitted to vibration for a number of hours in a type of 
 shaking machine. This is best constructed in such a way 
 that the vessel containing the explosive is raised by a cam 
 or sprocket wheel and lever and then allowed to drop 
 back on to a metal stop. After a period of vibration the 
 top layer and the bottom layer of the explosive are collected 
 separately and analyzed. 
 
 DEUQUESCENCE 
 
 The capacity of an explosive to absorb moisture from the 
 air is an important point, especially with those explosives 
 which contain highly hygroscopic salts such as nitrate of 
 ammonia or soda, as the absorption may reach such a point 
 that the explosive can no longer be detonated, or in the case 
 of nitroglycerine explosives the water taken up may displace 
 the nitroglycerine and thus give rise to danger. The deli- 
 quescence of an explosive depends chiefly on its constituents, 
 but is also influenced by the method of incorporation, non- 
 deliquescent ingredients such as nitroaromatic compounds 
 acting to some extent as waterproofing when the incorpora- 
 tion has been carried out hot. Deliquescence being a surface 
 
SENSITIVENESS AND STABILITY 215 
 
 action also naturally depends on the size of the grain and 
 on the porosity. In examining an explosive for deliquescence 
 the most satisfactory method is to compare its behaviour 
 in this respect with another explosive under similar circum- 
 stances. This is very simply done by spreading known 
 weights on watch glasses and then exposing them to the 
 atmosphere for the same number of hours and noting the 
 increase in weight. As the humidity of the atmosphere 
 varies from day to day it is better to expose the samples 
 in a closed cupboard maintained at a constant temperature, 
 the humidity of the air being maintained by flat dishes 
 containing water or saturated solutions of salts. 
 
 EXUDATION 
 
 The British Home Office regulations for testing for 
 exudation lay down that a section of the cartridge approxi- 
 mately equal in length to its diameter shall be cut so that 
 the ends are flat and the edges sharp. This is then pinned 
 on to a flat surface with its axis vertical by a pin passing 
 through the centre and exposed to a temperature of 85 to 
 90 Fahr. (29-4 to 32-2 C.) without any wrapper for 144 con- 
 secutive hours, at the end of which time the upper cut 
 surface must still be flat and the edges sharp, and the diminu- 
 tion of height must not exceed 25 per cent. American 
 Straight Dynamites are very apt to exude nitroglycerine 
 through absorption of water, and in the United States three 
 tests are in use. In one the explosive is pressed for i minute 
 between pads of cotton wool at 80 Ibs. per square inch and 
 must not show a loss of more than 3 per cent. In the 
 second test it is submitted to centrifugal force when enclosed 
 between cotton wool, and again in this case the loss must 
 not exceed 3 per cent. Finally it is placed in a vertical 
 position and heated for 6 days at 40 C. 
 
 INTERNATIONAL COMMITTEE 
 
 In 1912 the International Committee on Tests for 
 Explosives recommended that the following tests should 
 
216 EXPLOSIVES 
 
 be applied to explosives in order to ascertain their safety 
 for transport : 
 
 I. Preliminary Test 
 
 Two samples each of ten grams of the non-desiccated 
 explosive are placed in glass capsules fitted with a cover 
 and having a diameter of 35 mm. and a height of 50 mm. 
 The samples are heated to 75 C. for 4 hours, and at the end of 
 that time no decomposition or change in appearance must 
 have taken place, and no smell must be noticeable. 
 
 II. Mechanical Shock 
 
 The explosive is dried and powdered, and '05-* 10 gram 
 is spread on a steel anvil in a layer 1*27 cm. in diameter and 
 tested by the falling weight. The explosive must not be 
 more sensitive than an equal weight of pure, dry powdered 
 picric acid when tested under exactly similar conditions. 
 
 III. Friction 
 
 The explosive is ground in an unglazed porcelain mortar 
 at a temperature of 25-30 C., and its behaviour compared 
 with that of picric acid under similar treatment. 
 
 IV. Fire 
 
 (a) Three grams of the explosive are tapped down into 
 a glass test tube and its behaviour towards slow-burning 
 safety fuse tested. If it ignites it must be classified as 
 deflagrating and easily inflammable. 
 
 (b) The explosive is thrown into a hemispherical iron 
 dish, 12 cm. in diameter, at a red heat. At first only -5 
 gram of the explosive is used, but if this does not explode 
 or ignite the amount is gradually increased to 5 grams. 
 
 (c) One hundred grams are placed on a sheet of asbestos 
 board and then touched with an iron rod 15 mm. in diameter 
 heated to a cherry-red heat (about 900 C.). The explosive 
 should only burn slowly, and must not detonate. The 
 ignition should die out when the hot rod is removed. 
 
 The Committee printed their recommendations in both 
 French and English, but the English version is so 
 
SENSITIVENESS AND STABILITY 217 
 
 ungrammatical that the foregoing description is abstracted 
 from the French. 
 
 THE HEAT TEST 
 
 The test known as the Heat Test was originally intro- 
 duced by Abel for testing the stability of guncotton, and 
 depends upon the time required to produce a given tint in 
 starch-iodide paper when the explosive is heated under 
 standard conditions. The exact conditions under which 
 the test is carried out have been modified from time to time, 
 but in 1909 the British Government appointed a depart- 
 mental committee to investigate the whole matter and to 
 specify standard conditions for the test as applied to ex- 
 plosives of various classes, and this committee presented its 
 First Report in 1914. In Great Britain the Heat Test is the 
 standard test of stability applied to all explosives, and unless 
 an explosive satisfies this test it may neither be sold nor 
 transported. Owing to the great importance lent to the 
 test by these regulations the conditions under which it is 
 carried out will be described in some detail. 
 
 In carrying out work with the heat test it must be borne 
 in mind that it is exceedingly sensitive, and hence the most 
 scrupulous cleanliness is absolutely essential. A special 
 room must be devoted to it, the floor and walls of which 
 are washed at frequent intervals, no reagents other than 
 those required for the test should be allowed into the room, 
 and the room should be situated as far as possible from the 
 acid department. The room should be entered by as few 
 people as possible, and the operator must wash his hands 
 and rinse them with distilled water at frequent intervals. 
 Direct sunlight should also be excluded from the room. 
 
 Most factories, especially those holding Government 
 contracts, purchase their test papers from the Royal Gun- 
 powder Factory at Waltham Abbey, but the following official 
 regulations have been laid down for their preparation : 
 
 The purest potassium iodide obtainable commercially 
 is to be purified immediately before use by triple recrystalli- 
 zation from pure ethyl alcohol diluted with one-twentieth 
 
218 EXPLOSIVES 
 
 of its own volume of distilled water. The crystals are to 
 be kept as small as possible and are to be dried in the dark 
 on clean filter paper resting on a glass plate. When dry 
 they are to be laid in a thin layer at the bottom of a platinum 
 crucible and heated to dull redness for one minute, a .spirit 
 lamp burning pure alcohol being used. 
 
 The starch is to be best maize starch in the form of 
 cornflour. Immediately before use it is washed six times 
 with freshly distilled water, and then dried in a warm room 
 in the dark on an unglazed porcelain plate. 
 
 The solution is prepared by suspending 3 grams of 
 starch in 30 c.c. of distilled water and then pouring the 
 suspension into 220 c.c. of freshly distilled boiling water 
 contained in a Jena glass flask. The whole is then kept 
 gently boiling, with occasional shaking, for 5 minutes, a 
 spirit lamp burning pure alcohol being used. The solution 
 thus obtained is poured into a solution of i gram of potassium 
 iodide in 250 c.c. of distilled water, and the whole well mixed 
 and allowed to stand overnight in a dark room. The follow- 
 ing day the clear supernatant liquid is syphoned off and 
 immediately used for dipping. This is done by pouring the 
 solution into a porcelain tray reserved for the purpose, and 
 then passing sheets of filter paper through it singly so that 
 all except 3 cm. at the end of the strip passes beneath the 
 surface of the liquid. The paper is then hung up by the dry 
 part and a clean glass rod passed down each side to remove 
 the excess of solution, after which it is allowed to dry in a 
 warm dark room. When dry the undipped part is cut off, 
 and also strips -5 cm. wide round the edges, these portions 
 being rejected. The remainder is then cut into rectangular 
 slips 2 cm. long and i cm. wide and preserved for use 
 in brown glass bottles. While cutting up the paper the 
 operator is to wear clean cotton gloves, and the preparation 
 of the paper is to be carried out in a special room reserved 
 for the purpose and kept as dark as is compatible with the 
 carrying out of the work. The Memorandum issued by the 
 committee describes a method of testing the sensitiveness 
 of the papers thus prepared. 
 
SENSITIVENESS AND STABILITY 219 
 
 The quality of the filter paper used is of considerable im- 
 portance, and the committee have as yet been unable to fix a 
 definite specification, but suggest the following tentatively : 
 
 (1) To consist entirely of pure normal cotton cellulose of 
 strongly resistant quality and free from any loading or sizing. 
 
 (2) To have a smooth white surface, both sides being as 
 nearly alike as possible. 
 
 (3) The average length of the fibres to be 2 -5 mm. 
 
 (4) The thickness to be i '8 '2 mm. (Ciceri Smith's patent 
 fixed pressure micrometer). 
 
 (5) The last treatment in its preparation to be a thorough 
 washing with distilled water, and subsequent air drying in 
 a pure atmosphere. 
 
 (6) To be free from all impurity, particularly acids, 
 chlorine and peroxides. 
 
 (7) The loss of weight when boiled for i hour with 3 per 
 cent, caustic soda solution not to exceed 7-5 per cent. 
 
 (8) It is not to produce more than 1*25 per cent, of 
 its weight of cuprous oxide when heated to 100 C. for 
 15 minutes with Fehling's solution diluted with its own 
 volume of boiling water. 
 
 (9) The sheets are to measure 50 cm. by 15 cm. and are to 
 be packed in hermetically sealed tin cases holding 100 sheets 
 each. 
 
 The standard tint is prepared by shaking '48 gram of 
 finest yellow ochre, *2 gram raw umber and 5 grams of 
 fine white gum arabic, all of which have been very finely 
 ground in an agate mortar, with 100 c.c. of cold water until 
 the gum is dissolved. After standing for i hour a stylo- 
 graphic pen is filled from the centre of the suspension, and 
 with it lines not less than *5 mm. or more than i mm. wide 
 are ruled across filter paper. 
 
 This does not seem a very satisfactory method of pro- 
 ducing a standard tint, as commercial pigments are apt to 
 vary in shade, but a sealed pattern is kept at the Home Office 
 with which comparisons can be made. 
 
 The apparatus for carrying out the heat test consists of 
 a constant-level copper water-bath with seven equally 
 
220 EXPLOSIVES 
 
 spaced holes in the cover, one of these carrying the ther- 
 mometer and the other six the test-tubes containing the 
 explosives under examination. The level of the water is 
 J in. below the cover. The test-tubes are 5^ in. long, and 
 have three etched marks on them at 3 in., 3 in. and 5 in. 
 from the bottom respectively. The lowest of these indicates 
 the depth the tube is to be inserted in the bath, i.e. until 
 this line is level with the cover, the middle one indicates 
 the level of the lower moistened part of the test paper during 
 the test and the top line the level of the lower side of the 
 rubber cork. In carrying out the test the explosive is 
 prepared as described below and transferred to the test-tube. 
 A piece of test paper is then impaled on a platinum hook 
 sealed on to a glass rod, this latter passing through a rubber 
 cork, and the upper edge of the paper moistened with a 
 mixture of equal volumes of distilled water and pure glycerine 
 (B.P. specification). The rubber cork is then inserted into 
 the test-tube, and the whole slipped into one of the holes 
 in the cover of the water-bath and covered with an opaque 
 cap to exclude light. The temperature of the bath is 160 
 Fahr. or 170 Fahr., depending on the explosive being tested, 
 and the time is noted which elapses before the brown line 
 which appears at the margin of the wet and dry portions 
 of the paper matches the standard. 
 
 When setting up a test absolute cleanliness must be 
 observed, and on no account must the paper be touched 
 with the fingers, forceps being used. 
 
 In preparing explosives for the test, the end portions of 
 cartridges or sticks are always rejected. The following 
 outlines the methods employed for the different types of 
 explosives : 
 
 I. Dynamite and other nitroglycerine preparations from 
 which the nitroglycerine can be conveniently extracted with 
 water. 
 
 Thirteen grams of the explosive are evenly pressed down 
 with a glass rod on a filter paper supported by a 5j-cm. 
 glass funnel. The funnel is then placed in a heat test-tube 
 and filled with water. This displaces the nitroglycerine of 
 
SENSITIVENESS AND STABILITY 221 
 
 which 2 c.c. are collected, special heat test-tubes with a 
 mark corresponding to this amount being used. If any 
 water goes through with the nitroglycerine a fresh sample 
 of the explosive must be extracted. 
 
 II. Carbonite and similar friable preparations from which 
 the nitroglycerine cannot be conveniently extracted with water. 
 
 A sample weighing 3*2 grams is transferred to the heat 
 test-tube and pressed down to a height of 3 cm. by means 
 of a flat-headed glass rod. 
 
 III. Cordite and other Propellants of Class 3, Division i. 
 If the explosive is in sticks or tubes these are wiped with 
 filter paper, the ends cut off and rejected, and the remainder 
 then cut into pieces J in. long and ground and sieved, a 
 standard grinding mill and a standard nest of sieves being 
 specified by the committee. The weight of the ground and 
 sieved sample taken for the test is i'6 grams, this not being 
 pressed down but merely made to settle by tapping the 
 outside of the tube. If the explosive is in grains it is not 
 ground or sieved. Nitrocellulose propellants when in sticks 
 or tubes are treated in the same way. 
 
 IV. Nitrocellulose Pulp. 
 
 The explosive is pressed between six thicknesses of 
 filter paper, and 5 grams of the pressed pulp weighed out 
 and dried at 48*9 C. on an aluminium tray for 15 minutes. 
 The dried sample is then sieved under standard conditions, 
 exposed to the air for 4 hours, and then 1*3 grams weighed 
 out, transferred to the heat test-tube and pressed down 
 gently to a height of 3 cm. 
 
 Nitrocellulose propellants in grains are tested in the 
 same way as guncotton pulp, except that they are not 
 sieved and the preliminary pressing between filter paper is 
 of course dispensed with. 
 
 V. Compressed Guncotton. 
 
 Scrapings are taken from the centre of the slab by means 
 of a horn spatulum and stirred for 15 minutes with cold 
 distilled water. The water is then poured off and the 
 process repeated, after which the guncotton is treated in 
 exactly the same way as guncotton pulp. 
 
222 EXPLOSIVES 
 
 VI. Bellite and Analogous Preparations. 
 
 The weight taken is 1-3 grams, and this is gently tapped 
 to the bottom of the test-tube. 
 
 VII. Gelatinized Explosives. 
 
 A sample weighing 3-2 grams is weighed out and ground 
 up with 6*5 grams of French chalk in a Wedgwood pestle and 
 mortar, the grinding being carried out at first with a squeez- 
 ing and then with a circular movement of the pestle. With 
 Blasting Gelatine the squeezing movement is carried on for 
 i J minutes, with Gelatine Dynamite for i minute, and with 
 Gelignite for J minute, the circular movement being in all 
 cases maintained for J minute, after which the mass should 
 be homogeneous in appearance. The mixture is gently 
 pressed down in the heat test-tube to a height of 5 cm. 
 
 The committee found that different qualities of French 
 chalk give different results when used for heat test purposes, 
 but they were unable either to find a substitute or propose 
 a definite specification. As a tentative measure they suggest 
 the following : 
 
 (1) It must not contain more than *5 per cent, of moisture. 
 
 (2) Its bulk must be such that 50 c.c. without ramming 
 or tapping weigh 23*5 i gram. 
 
 (3) It must pass a sieve composed of wire '075 mm. in 
 diameter and having 6400 meshes to the square centimetre, 
 no rubbing being used. 
 
 (4) It must contain less than 'i per cent, of soluble 
 alkali calculated as CaCO 3 . 
 
 (5) When warmed with hydrochloric acid it must give 
 off at least -25 per cent, of carbon dioxide, but not more 
 than i per cent. 
 
 (6) It must not absorb more than -5 per cent, of moisture 
 when exposed for 24 hours to a saturated atmosphere at 
 I5-20 C. after being dried at 100 C. 
 
 Before use it is washed with distilled water, dried at 
 65-70 C., and then exposed to a saturated atmosphere for 
 24 hours. This cannot be said to be a satisfactory definition, 
 and it should not be impossible to obtain a more definite 
 chemical compound suitable for the purpose, 
 
SENSITIVENESS AND STABILITY 223 
 
 The following table shows the temperature and amount 
 of the different explosives used, together with the minimum 
 time in minutes they are required to stand : 
 
 Explosive. 
 
 Quantity. 
 
 Tempera- 
 ture. 
 
 Time. 
 
 Nitroglycerine extracted from Dynamite 
 Friable nitroglycerine explosives 
 
 2 C.C. 
 
 3' 2 grams 
 
 160 F. 
 160 F. 
 
 15 
 
 7 
 
 Gelatinized explosives 
 
 +6'5 ',', \ 
 
 1 60 F. 
 
 10 
 
 
 French chalk j 
 
 
 
 Cordite and other nitroglycerine pro- 
 
 
 
 f^ 
 
 pellants 
 
 i '6 grams 
 
 160 F. 
 
 IO 
 
 Nitrocellulose, pulp or compressed 
 
 1-3 
 
 I70F. 
 
 10 
 
 Nitrocellulose propellants 
 Bellite, and the like 
 
 1-3 ;; 
 
 170 F. 
 170 F. 
 
 10 
 10 
 
 Cordite Mark I. and Cordite M.D. 
 
 
 
 
 (Government Contracts) 
 
 1-6 
 
 180 F. 
 
 30 
 
 The heat test has been adopted by most countries either 
 alone or, more usually, in conjunction with other tests as 
 the standard method of measuring stability, but the details 
 of its application naturally differ in some respects from 
 those in force in Great Britain. It would be a great con- 
 venience if an international method of carrying out the test 
 could be established and adopted by all countries. The 
 test suffers from the disadvantages of being too sensitive, 
 and of being masked by minute traces of certain chemicals 
 such as mercuric chloride. Alcohol and ethyl acetate 
 prolong it, and consequently it is not very reliable for 
 nitrocellulose propellants which have been gelatinized by 
 these solvents. On the other hand, ozone or peroxide if 
 present in minute traces greatly reduce it, and so does oxalic 
 acid, although it probably does not affect the real stability. 
 
 As a manufacturers' guide the test is undoubtedly useful, 
 but as a guarantee of stability far too much reliance would 
 seem to be placed on it, as unless a very careful analysis of 
 the explosive is made at the same time it is quite possible 
 that really unstable explosives might pass the test, whereas 
 really stable ones might fail. The test is really too sensitive, 
 135 X io~ 6 mgr. of nitrogen peroxide being sufficient to 
 produce the standard tint. It* is difficult, however, to 
 
224 EXPLOSIVES 
 
 propose a more satisfactory test, although several attempts 
 have been made to do so. These may be divided into three 
 broad classes, viz. tests similar in nature to the Abel heat 
 test, in which reliance is placed on the detection of traces of 
 oxides of nitrogen ; tests in which the explosive is submitted 
 to more drastic treatment and which rely on the production 
 of visible fumes, self -heating or explosion ; and quantitative 
 tests, in which the quantity of oxides of nitrogen is actually 
 measured. Of the trace tests may be mentioned the Gutt- 
 mann, Spica and Moir tests. Of these the first relies on the 
 production of colour in a paper impregnated with a solution 
 of diphenylamine and dilute sulphuric acid. It is not 
 masked by mercuric chloride or by alcohol or ethyl acetate, 
 and is in use in some countries, although its reliability has 
 been criticized. Spica's test is similar, except that m- 
 phenylenediamine and cane sugar are used, but it is far too 
 sensitive. Moir's test, on the other hand, employs a mixture 
 of a-naphthylamine, sulphanilic acid and acetic acid, and 
 is even more sensitive. 
 
 Vieille's test involves more drastic treatment of the 
 explosive, and a much less sensitive indicator is used, viz. 
 litmus paper. It is carried out by heating the explosive 
 on successive days for 8 hours to 110 C. or until the test 
 paper assumes the standard tint. This process is repeated 
 daily until the time is reduced to i hour, and the sum of 
 all the times then taken as a measure of stability. Although 
 officially adopted in France, the test must be regarded as 
 a very crude one. 
 
 A somewhat more satisfactory test of a similar nature is 
 used in Germany. In this test the explosive is heated under 
 standard conditions at 135 C. (the boiling point of xylol), 
 and the time noted which elapses before (i) litmus paper is 
 reddened ; (2) brown fumes become visible ; (3) explosion 
 takes place. If many samples are to be tested it is a some- 
 what tiresome test to carry out owing to the explosion. 
 
 Another test depending on the production of brown fumes 
 has been introduced for testing Mark I. Service Cordite, 
 which has been in stock for some time, and the heat test 
 
SENSITIVENESS AND STABILITY 225 
 
 of which has fallen to between four and eight minutes at 
 160 F. The test is applied by placing 50 grams of the 
 ground Cordite in a vacuum- jacketed silvered flask heated 
 by a water-bath to 80 C. A sensitive thermometer is in 
 contact with the Cordite, and the neck of the vessel is 
 provided with a side tube. Observations are made of the 
 interval of time that elapses before (i) brown fumes are seen 
 in the side tube ; (2) the Cordite begins to heat spontane- 
 ously ; (3) the spontaneous rise in temperature reaches 2 C. 
 The test is known as the Waltham Abbey Silvered Vessel Test. 
 
 Of the quantitative tests, the best known is that devised 
 by Will. This is carried out by heating the explosive to 
 135 C. in a current of pure carbon dioxide, the rate of flow 
 of the gas being 1000-1500 c.c. per hour. The carbon dioxide 
 and gases evolved by the explosive are then led over 
 heated cupric oxide and metallic copper in order to oxidize 
 any organic matter and to reduce oxides of nitrogen to 
 elementary nitrogen. Finally, they are collected over 40 
 per cent, caustic potash in order to absorb the carbon dioxide. 
 The volume of nitrogen thus obtained is noted at regular 
 intervals during the test, and from the figures thus obtained 
 a very good idea of the rate of decomposition of the explosive 
 can be formed. 
 
 Other tests of a similar nature have been devised, but 
 they present little if any advantage over the Will test. 
 
 LITERATURE 
 MECHANICAL SHOCK 
 
 A friction test which has been adopted in America is described in the 
 Bulletin of the U.S Bureau of Mines, No. 66, pp. 15 and 290. 
 
 The falling weight test is described in the following publications : 
 
 " VI. International Congress of Applied Chemistry," vol. 2, p. 522. 
 
 " VII. International Congress of Applied Chemistry," Section III., p. 23. 
 
 S.S., 1906, pp. 14, 209. Bulletin of U.S. Bureau of Mines, No. 66, 
 pp. 17, 287. Marine- Rundschau, 1905, 1345. 
 
 DETONATION AND INFLUENCE 
 
 Z. ang., 1904, 546. 
 P.S., 1913, p. 145. 
 
 " VH. International Congress of Applied Chemistry," vol. iii. b, p. 30. 
 Bulletin of the U.S. Bureau of Mines, No. 15. 
 T. 15 
 
226 EXPLOSIVES 
 
 EXUDATION 
 
 U.S. Bureau of Explosives Reports, Nos. 2 and 4. 
 S.S., 1910, p. 213. A.E., 1914, pp. 150, 162. 
 
 INTERNATIONAL COMMITTEE 
 
 " VIII. International Congress of Applied Chemistry," vol. 25, pp. 261, 
 305. 
 
 HEAT TEST, ETC. 
 
 Very full directions for the application of the Heat Test will be found 
 in " First Report of the Departmental Committee on the Heat Test as 
 Applied to Explosives," published by Authority, London, 1914. This 
 publication gives detailed drawings of the apparatus required. Some 
 United States conditions will be found in A. Marshall, " Explosives," 
 vol. ii., London, 1917, and in E. C. Worden, " Nitrocellulose Industry," 
 vol. ii., London, 1911. 
 
 Several papers describing research work on the test have appeared 
 from time to time, of which /. S.C.I., 1910, 130, is of particular interest. 
 
 Guttmann described his test in J. S.C.I., 1897, 293. See also S.S., 1912, 
 
 P- I 53- 
 
 Moir's Test and Egerton's modification of it are treated in J. S.C.I., 
 
 1913. 33*. and J 9*4 Ir 3- 
 
 Vieille's Test is described by R. Escales in " Schiessbaumwolle/' p. 184, 
 and in E. C. Worden, " Nitrocellulose Industry," vol. ii. p. 969. 
 
 The best descriptions of the German test at 135 C. will be found in 
 R. Escales " Schiessbaumwolle," p. 183, and in E. C. Worden, " Nitro- 
 cellulose Industry," p. 971. 
 
 A. Marshall also gives a short description of it in his book " Explosives," 
 vol. ii. p. 662. 
 
 The Waltham Abbey Silvered Vessel Test is described in " Regulations 
 for Army Ordnance Services," published by Authority (1908). 
 
 Will's Quantitative Test has been studied by Robertson in J.S.C.I., 
 1902, 819, and Soc., 1907, 761. Further descriptions of the test will be 
 found in 
 
 R. Escales " Schiessbaumwolle," p. 186. 
 
 E. C. Worden, " Nitrocellulose Industry," p. 974. 
 
 The following references deal with other tests of a similar nature : 
 
 Z. ang., 1904, 982 ; J. S.C.I., 1905, 347 ; 1912, 161. 
 
 /. Am. Chem. Soc., 30, 271 ; Soc., 1907, 764. S.S., 1905, p. 29 ; 1910, 
 p. 121. P.S., xiv. p. 42. A.R., 1903,26; 1904,28; 1905, 28. "VIII. 
 Congress of Applied Chemistry," vol. iii. b, pp. 147, 157. Also R. Escales, 
 "Schiessbaumwolle," pp. 177-198; E. C. Worden, "Nitrocellulose In- 
 dustry," pp. 968-984. 
 
CONCLUSION 
 
 IN surveying the ingredients which so far have been found 
 suitable for use in the manufacture of explosives, one is at 
 once struck by the paucity of the number of oxidizing 
 agents available. Of organic compounds only one, viz. 
 nitroglycerine, contains more oxygen than is necessary for 
 its complete oxidation. It is true that one or two compounds 
 such as tetranitro methane contain an excess of oxygen, 
 but they are difficult to obtain, and even if obtained have 
 objectionable qualities such as intense toxic action. Nitro- 
 mannitol, of course, has some available oxygen, but it is 
 too expensive for general use, and other possible compounds 
 such as dinitro tartaric acid are far too unstable. As it is 
 theoretically impossible to obtain a nitroaromatic hydro- 
 carbon with available oxygen, the unknown hexanitro- 
 benzene would only contain just enough for its complete 
 oxidation, the chances of obtaining a suitable organic 
 oxidizing agent would seem very remote. Of the inorganic 
 oxidizing agents available, only three classes are of any 
 importance, viz. the nitrates, chlorates and perchlorates, 
 although bichromates have been used to a very minor 
 extent. 
 
 Of these the nitrates are the cheapest, but unfortunately 
 the most suited of them, viz. ammonium nitrate, has the 
 objectionable quality of being very hygroscopic. In spite 
 of this it has met with wide application, and is probably 
 destined to be employed to a far greater extent in the near 
 future owing to the production of cheap ammonia by the 
 Haber process and of cheap nitric acid by the oxidation of 
 this or directly from the air by electrical means. Up to 
 
228 EXPLOSIVES 
 
 the present waterproofing the cartridges with wax has 
 been chiefly relied on as a means of preventing the absorption 
 of water by the explosive, although one or two explosives 
 are put up in cases made of an alloy of tin and lead. These 
 are objectionable, however, in underground workings owing 
 to the poisonous nature of the lead oxide produced. Possibly 
 aluminium foil may prove more suitable as its oxide is not 
 poisonous, and the heat of combustion of the foil would 
 considerably increase the power of the explosion. It should 
 be noted that ammonium nitrate, with the exception of 
 ammonium perchlorate, is the only inorganic oxidizing agent 
 giving no solid products. 
 
 Of the other nitrates, sodium nitrate is the cheapest, but 
 suffers from the same disadvantage as ammonium nitrate, 
 only to a lesser extent. Potassium nitrate has not this 
 disadvanatge, but is much higher in price. Neither barium 
 nor lead nitrate is hygroscopic, but unfortunately both 
 barium and lead salts are very poisonous, so that neither 
 of these salts is suited for use as an ingredient in explosives 
 for use underground, and in addition to its toxic properties, 
 lead nitrate reduces the velocity of detonation to a great 
 extent. As a class the nitrates, and particularly those of 
 ammonium, sodium, and potassium, are likely to hold the 
 premier place as oxidizing constituents in explosives. In 
 this connection it should be pointed out that the synthetic 
 nitric acid processes are at present more suited to the 
 production of nitrates than to the production of nitric acid. 
 In all these processes it is not nitric acid but nitric dioxide 
 that is produced, and although this can be converted into 
 nitric acid by the action of water and air 
 
 3NO 2 + H 2 = 2HN0 3 + NO 
 NO + O = NO 2 
 
 this can only be done at present by means of an elaborate 
 system of towers, the gases flowing in one direction and the 
 liquor being circulated from the bottom of one tower to 
 the top of the next on the counter-current principle. Pump- 
 ing straight nitric acid is always troublesome, and although 
 
CONCLUSION 229 
 
 it can be achieved with ferro-silicon pumps or in glass or 
 stoneware pipes by the air-lift, the former are expensive 
 and the latter inefficient. In any case, the towers yield an 
 acid of a strength not exceeding 60 per cent., which is too 
 weak for most nitrations, and it can only be concentrated 
 by distillation with sulphuric acid, calcium nitrate or other 
 suitable dehydrating agent. The methods of concentration 
 will no doubt be greatly improved in the near future, but 
 in the meantime the weak acid is quite suitable for making 
 nitrates, as it is only necessary to neutralize it with the base 
 and then evaporate the solution. Of course only a small pro- 
 portion of the nitrate made will be used for the production 
 of explosives, the bulk being manufactured for agricultural 
 purposes. It may be remarked in passing that the use of 
 synthetic nitric acid will go a long way towards simplifying 
 the chemical engineering side of plant construction, as the 
 synthetic acid, unlike that obtained from Chili saltpetre, 
 contains no chlorine and is consequently much less corrosive. 
 Probably chrome steel will be found quite suitable for 
 handling it, although this alloy is badly attacked by 
 commercial nitric acid made from Chili saltpetre. 
 
 Of the chlorates, only the potassium salt is used to any 
 extent, the sodium salt being too deliquescent and the 
 ammonium salt unstable. Even the potassium salt is 
 never likely to be much used except for the production of 
 matches, as Cheddite is about the only chlorate mixture 
 which is not unduly sensitive, or likely to become so on 
 keeping. 
 
 The perchlorates are more stable than the chlorates, 
 from which they are obtained by electrolysis, and in addition 
 they contain more oxygen. Before the war their use was 
 on the increase, and the erection of a large factory for their 
 production for war purposes should lead to their increased 
 application. It is interesting to compare the prices of 
 nitrates, chlorates and perchlorates, and the following figures 
 for the potassium salts are based on prices current in 1910. 
 The figures are in shillings per 100 Ibs. of salt and in shillings 
 per Ib. of available oxygen : 
 
230 EXPLOSIVES 
 
 Price per cwt. 
 Salt. 
 
 Per cent. 
 Available 
 Oxygen. 
 
 Price per Ib. 
 Available 
 Oxygen. 
 
 :'; 
 
 47 
 66 
 80 
 
 40 
 39'3 
 
 4 6 '3 
 
 I-I7 
 
 1-68 
 173 
 
 KN0 3 
 
 KClOg 
 
 KC1O 4 
 
 The fact that the perchlorate is slightly more expensive 
 than the chlorate per unit available oxygen is more than 
 counterbalanced by increased safety, but it is difficult to 
 see how perchlorates can ever compete with nitrates for 
 general purposes, especially in view of the production of 
 cheap nitric acid in the near future, although they will no 
 doubt be increasingly used for special purposes. Ammonium 
 perchlorate, like ammonium nitrate, gives no solid matter, 
 but unfortunately it gives chlorine, and so can only be used 
 in conjunction with an alkali or alkali earth nitrate or organic 
 salt to provide a base with which the chlorine can combine. 
 It is practically non-hygroscopic, and cost (pre-war) about 
 5f^. per Ib., this corresponding to 3*8 shillings per Ib. 
 of available oxygen. This figure must not be compared 
 with those given above for the potassium salts as ammonium 
 perchlorate is an explosive in itself 
 
 2NH 4 C10 4 = 4H 2 + C1 2 + N 2 + 2O 2 
 
 In spite of the disadvantage of producing chlorine the 
 salt is likely to find considerable application, as it seems to 
 assist the detonation to spread provided a strong enough 
 detonator or primer is used. 
 
 Turning now to the combustible matters, these are 
 chiefly nitroaromatic hydrocarbons, and to produce a really 
 satisfactory explosive they should for preference be capable 
 of exploding alone. At present the nitro derivatives of 
 benzole and toluol are chiefly used, and to a lesser extent 
 the nitro derivatives of naphthalene. This latter hydro- 
 carbon, like all condensed nuclei compounds, suffers from the 
 disadvantage that the number of nitro groups that can be 
 introduced is smaller in proportion to the number of carbon 
 atoms than is the case with uncondensed nuclei, and for 
 this reason derivatives of fluorene, acenaphthene, pyrene, etc., 
 
CONCLUSION 
 
 231 
 
 although they will probably come into use in the dye stuff 
 industry, are not likely to be employed in the manufacture 
 of explosives even if produced at a sufficiently low price. 
 This is made clear in the following table, in which is shown 
 the number of atoms of oxygen per molecule of compound 
 and the grams of oxygen per hundred grams of compound 
 which are necessary for complete oxidation : 
 
 
 
 Extra Oxygen required. 
 
 
 Molecular 
 
 
 
 weight. 
 
 _ 
 
 
 
 Atoms per mol. jo^Tg^ms. 
 
 Dinitrobenzole 
 
 168 
 
 10 94*4 
 
 Trinitrobenzole 
 
 213 
 
 ?i 5 6 '4 
 
 Dinitrotoluol 
 
 182 
 
 I 3 II 4 
 
 Trinitrotoluol 
 
 227 
 
 Io i 74 
 
 Trinitronaphthalene . . 
 Tetranitronaphthalene 
 
 263 
 
 308 
 
 i6 loo 
 16 83-1 
 
 Trinitrobenzole shows up best, but unfortunately it is 
 too expensive to produce. It is notable that no catalyst 
 for facilitating nitration has yet been discovered. Such a 
 catalyst would be most valuable, and might have a great 
 influence on explosives manufacture. 
 
 It seems improbable that for general purposes much 
 progress is to be expected in the way of production of new 
 combustible matters, although exhaustive nitration may, 
 and probably will, lead to the production of highly nitrated 
 compounds like tetryl which, although suitable for special 
 purposes such as for initiators, are too expensive for general 
 blasting use. The numerous trinitrotoluol plants put down 
 for war purposes and the experience gained in the manu- 
 facture of this substance render it probable that it will 
 become the standard combustible. In any case, the amount 
 held in stock for military purposes will probably suffice to 
 supply the needs of the explosives works for some time if it 
 is disposed of as " surplus stores." 
 
 Up to the present Gelignite has been the standard high 
 explosive for general blasting purposes, and nitroglycerine 
 explosives have also been very widely used in coal mines, 
 but it is doubtful if nitroglycerine explosives will retain their 
 
232 EXPLOSIVES 
 
 supremacy much longer. The production of cheap ammo- 
 nium nitrate and cheap T.N.T. will certainly give a great 
 impetus to explosive mixtures composed of these ingredients, 
 and as their manufacture is cheap and safe so that very 
 little explosion risk has to be carried it should be possible 
 to put them on the market at a very low price, thus enabling 
 their use to become more general, e.g. for agricultural work. 
 Whether the Merger Company (Explosives Traders, Ltd.) 
 which now controls practically the whole explosives trade 
 in Great Britain will do so or not remains to be seen. If 
 not it is probable that the big mine owners will manufacture 
 their own explosives, more especially as the big coal mine 
 companies usually also own by-product coke oven in- 
 stallations, and will no doubt be among the first to instal 
 synthetic ammonia plants. Mixtures of T.N.T. and am- 
 monium nitrate can be made up to be as powerful as Gelig- 
 nite, and by adding aluminium powder extremely powerful 
 explosives of the Ammonal class can be obtained. Of 
 course there is always the difficulty of deliquescence, but 
 the present waxed paper wrappers are more or less satis- 
 factory and are capable of improvement, and the introduction 
 of aluminium foil cases would seem to be quite feasible. 
 
 The future is likely to see considerable improvement in 
 detonators, and probably the ordinary fulminate-chlorate 
 detonator will be very largely replaced by the composite 
 detonator made with lead azide, unless further research 
 brings to light a more satisfactory initiator. 
 
 The probable development of the propellant branch of the 
 industry is more difficult to forecast, although minor improve- 
 ments will be brought about in manufacturing details. No 
 great departure from present day composition is to be looked 
 for until some smokeless oxidized agent is discovered which 
 has suitable properties. Of the only two available at present, 
 ammonium nitrate is far too deliquescent, and ammonium 
 perchlorate corrodes the barrel too much to be used. Unless 
 such an oxidizing agent is found any great departure from 
 present day compositions could only be made by the intro- 
 duction of some " combustible matter " containing sufficient 
 
CONCLUSION 233 
 
 oxygen to explode without the production of smoke, i.e. con- 
 taining enough oxygen to convert the hydrogen into water 
 and the carbon into monoxide. Both trinitrobenzene and 
 tetryl almost satisfy these conditions, and an almost smoke- 
 less powder could be produced from them by adding a little 
 potassium nitrate. Unfortunately such mixtures are far 
 too brisant for use as propellants, and at present it is not 
 easy to see how their combustion is to be regulated. A 
 propellant made from definite pure chemical compounds 
 would have many advantages over those composed of 
 indeterminate mixtures like nitrocellulose, but no success 
 has yet been achieved in this direction. Of course, nitro 
 starch may become a commercial success, but it is little 
 more definite in nature than nitrocellulose. 
 
 In recent years a considerable number of patents have 
 been taken out covering the use of stabilizers, and more 
 progress is to be looked for in this direction, a stabilizer 
 being desired which does not have a bad effect on the 
 ballistic properties of the propellant and which does not 
 mask stability tests, thus giving rise to a false belief in 
 security. 
 
 The war has shown to what an extent the dyestuffs, 
 explosives and fertilizer trades are interdependent, and the 
 advent of synthetic nitrates will make them even more so. 
 It is notable that one of the largest explosive producers in 
 the world, B. A. du Pont de Nemours (U.S.A.), is now 
 concentrating on synthetic dyestuffs, and that in this country 
 Nobel's Explosives Company, L,td., now merged into Ex- 
 plosives Trades, lytd., have acquired a large interest in the 
 dyestuff combine. Whether this tendency to concentrate 
 business in the hands of one combine will ultimately benefit 
 the consumer or not is doubtful, although it will no doubt 
 benefit the shareholders. 
 
INDEX 
 
 A I MONOBEL, 134 
 
 A 2 Monobel, 134 
 Abel, 3, 137 
 
 heat test, 208, 217-224 
 
 process, 3, 45 
 Abelite No. i, 132, 133 
 
 No. 4, 131 
 Accidents, 9 
 Acetic acid, 88 
 
 Ether. See Ethyl acetate. 
 Acetone, 74, 85, 88 
 
 recovery, 77, 78 
 Adler-Marke, 87 
 After-flame, 119 
 
 ratio, 118, 119 
 
 separation, 34, 35 
 Ageing, 84 
 Ajax powder, 137 
 Alcohol, 87, 88 
 
 -ether. See Ether-alcohol. 
 Alcoholizing, 52 
 Aldehyde, 88 
 Aldorfit, 189, 195 
 Alum, 164 
 Aluminium powder, 112-114, 176, 
 
 177 
 
 Amberite, 86 
 Ammonal, 114, 195, 232 
 Ammon-Carbonite, 118, 194 
 Ammonia Dynamite, 98, 191, 192 
 Ammonite, 133 
 
 No. i, 127, 131, 133 
 
 No. 4, 131, 133 
 
 No. 5, 127, 133 
 Ammonium bichromate, 31, 86, 87 
 
 chloride, 120, 131 
 
 nitrate, 4, 11, 12, 31, 92, 97, 
 98, 113-115, 199, 228, 232 
 
 oxalate, 132 
 
 perchlorate, 31, 92, 106, 107, 
 112, 113 
 
 phosphate, 164 
 
 picrate ,211 
 
 Ammunition, Definition of, 13 
 Amyl acetate, 82 
 
 alcohol, 81 
 Anchorite, 132, 133 
 
 Antimony sulphide, 162 
 Arkite, No. 2, 136 
 Astralite, 113, 211 
 Atlas Powder, 97 
 Auer Metal No. 2, 170 
 Axite, 78 
 Azides, 28, 146 
 
 | BACK-FLASH, 69 
 Bacon, Roger, 1 
 Ballistic pendulum, 182-184 
 ! Ballistite, 5, 72 
 i Barium chlorate, 106 
 
 cuprothiosulphate, 167 
 
 nitrate, 82-86, 92, 228 
 
 perchlorate, 92, 106 
 
 sulphate, 94 
 Barriers, 8 
 
 Bashforth chronograph, 204, 205 
 Bellite No. i, 132, 133 
 
 No. 2, 132, 133 
 
 No. 4, 132, 133 
 Bengal Fire, 170-172 
 Benzene ozonide, 31 
 Berthelot, 197 
 Bichel, 118, 196, 197 
 
 recorder, 196 
 
 Black powder. See Gunpowder. 
 Blastine, 112 
 Blasting explosives, 90-116 
 
 Gelatine, 4, 9, 10, 91, 104, 118, 
 181, 182, 186, 194, 199,208, 
 210 
 
 Blending, 24, 76, 84 
 Bobbinite, 26, 119, 137, 138 
 Boiling nitrocellulose, 50 
 Bomb calorimeter, 197-200 
 | Borax, 137 
 Braun, 3 
 Brick dust, 93 
 j Briquets, 168 
 Brisance meter, 184 
 Britonite No. 2, 135, 136 
 
 No. 3, 135, 136 
 Buildings, 7 
 Bulk powders, 82-87 
 Butylene, 42 
 
236 
 
 INDEX 
 
 CALCIUM phosphide, 177 
 
 silicide, 114 
 Calorimetry, 197-200 
 Cambrite, 135 
 Cap composition, 147-149 
 Caps, Percussion. See Percussion 
 
 caps. 
 
 Carbo-Dynamite, 97 
 Carbonite, 98, 194, 199, 221 
 
 No. 2, 211 
 Cartridge machines, 94, 95, 101, 
 
 102, 115 
 
 Castor oil, 106, 112 
 Catherine wheels, 170, 174 
 Cellulose nitrate. See Nitrocellu- 
 lose; Guncotton; Collodion. 
 Centrifugal nitrator, 48 
 Cerium alloys, 168-170 
 
 chloride, 169 
 
 fluoride, 169 
 Chancel, 162 
 Charcoal, 18, 97 
 Charge limite, 122 
 Cheddite, 6, 10, 31, 106, 109-113, 
 
 189, 210 
 Chlorate explosives, 2, 5, 106-113 
 
 mixture, Definition of, 12 
 
 mixtures, 2, 5, 106-113 
 Chlorates, 31, 106 
 Chronograph, 202-205 
 Classification, 10-15 
 Coal Mine Explosives, 117-142 
 Cocoa powder, 18 
 Colliery Steelite, 111 
 Collodion cotton, 48, 49, 79-86, 
 
 211, 221 
 
 Coloured fire. See Bengal Fire. 
 Composite detonators, 154 
 Condensed powders, 82 
 Coolers, 120, 130, 131 
 Copper ammonium thiosulphate, 
 147, 148 
 
 sulphate, 26, 138 
 
 thiocyanate, 163 
 Cordite, 5, 71, 72-77, 221, 223 
 Cork dust, 108 
 Corning, 2, 23 
 Cotton, 44 
 Crackers, 170 
 Crusher gauge, 195. 196 
 
 DAHMENIT, 139 
 Definition of explosive, 6 
 Delayed action fuze, 159 
 Deliquescence, 214, 215 
 Denaby Powder, 132 
 Denitration, 64-66 
 Densite No. 3, 140 
 No. 4, 140 
 
 Deposit of washings, 37 
 
 Deterrents, 70 
 
 Detonating fuze, 158, 159, 187, 193 
 
 Detonation, 143, 211 
 
 Detonator, Definition of, 13 
 
 Detonators, 153-156 
 
 Heat of explosion of, 198 
 Devine, 4 
 
 Diazobenzene nitrate, 30, 147 
 Dieprez Chronograph, 204, 205 
 Diglycerine, 40, 41 
 Dinitro acetyl glycerine, 41, 103 
 
 benzole, 29, 52, 85, 185, 193, 
 210, 231 
 
 chlorbenzole, 59 
 
 chlorhydrin, 28, 40, 103, 139 
 
 diphenylamine, 63 
 
 formin, 41, 103, 104 
 
 glycerine, 40, 103, 139, 210 
 
 glycol, 28, 29, 41. 43, 103 
 
 naphthalene, 30 
 
 phenol, 59 
 
 tartaric acid, 28 
 
 toluol, 30, 52, 56, 85, 109, 193, 
 
 194, 231 
 
 Diphenylamine, 30, 71, 78, 81 
 Direct dipping process, 45 
 Displacement process, 45 
 Donarite, 118, 194, 211 
 Dorfit No. i, 139 
 
 No. 2, 139 
 
 Dreadnaught Powder, 133 
 Drowning tanks, 32, 35 
 Drying Cordite, 76, 77, 78 
 
 cotton, 45 
 
 fulminate, 146 
 
 gunpowder, 24 
 
 nitrocellulose, 51 
 
 propellants, 76, 84 
 Du Pont Permissible No. I, 134 
 Dusting, 24 
 Duxite, 136 
 
 Dynamite, 96, 97, 191, 192, 194, 
 220, 221 
 
 No. i, 9, 10, 93-96, 118, 181, 
 194, 199, 210 
 
 No. 2, 96 
 
 No. 3, 97 
 
 No. 4, 105 
 
 No. 5, 105 
 
 American, 96-98 
 
 antrigrisouteuse, 140 
 
 gelatinee, 105 
 
 pump, 94, 95 
 Dynammon, 139 
 Dynobel, 137 
 
 No. 2, 135 
 
 No. 3, 135 
 
 No. 4, 135 
 
INDEX 
 
 237 
 
 E.G. POWDER, 6, 86 
 Electric detonators, 155, 156 
 Erosion, 71 
 Ether, 74, 81 
 
 -alcohol, 44, 73, 74, 80, 81, 85 
 Ethyl acetate, 85, 87 
 Expedite, 132, 133 
 Explosif O a , 111 
 
 O 8 , 108 
 
 4 , 111 
 
 5 , 111 
 
 N i a bis couche, 141 
 
 N ib bis roche, 141 
 
 N ic bis roche, 141 
 
 N 2 roche, 141 
 
 N 3 roche, 141 
 
 N 4 couche, 141 
 
 type P, 109, 110 
 S, 109, 110 
 41, 111, 210 
 60, 111, 210 
 6o, 109, 110 
 Explosifs antigrisouteuses, 121, 141 
 
 couches, 122, 141 
 
 de surete, 121, 141 
 
 roches, 122, 141 
 
 S.G.P., 121 
 Explosive compounds, 28-66 
 
 Definition ot, 6 
 Explosives Act, 6 
 Extra-Carbonite, 194 
 Exudation, 104, 215 
 
 FALLING weight test, 209, 210 
 Fasan Powder, 87 
 Favier, 4, 113 
 
 2 bis, 140 
 
 explosives, 113 
 Ferrosilicon, 114 
 Filite, 78 
 
 Filter-house, 35, 36 
 Firework composition, 14 
 
 Definition of, 14 
 Fireworks, 170-177 
 Flame, 118-120 
 Flash lights, 176, 177 
 Frursheim, 6, 59 
 Forcite extra, 105 
 
 superieure, 105 
 
 No. i, 105 
 Forsyth, 2 
 Fouling, 69 
 Fractorite B, 140 
 French chalk, 222 
 Friction test, 208, 209, 216 
 Fulmenit, 113 
 Fulminate. See Mercury fulminate. 
 
 Definition of, 13 
 Fu7c, Definition of, 13 
 
 Fuze, Detonating, 158 
 Instantaneous, 158 
 Safety, 156 
 Shell, 2, 159, 160 
 
 GALLERIES, 6, 118-125 
 Gelatine Carbonit, 139 
 
 Dynamite, 4, 10, 104, 105, 182, 
 191, 192, 208, 210 
 
 Wetterastralit I, 139 
 Gelatinee, 105 
 
 iB, 105 
 
 Gelignite, 4, 9, 10, 91, 104, 105, 118, 
 181, 182, 191, 192, 194, 199, 
 208 
 Gesteins-Dorfit, 195 
 
 Westfalit, 114 
 Glass powder, 147 
 Glazing, 24 
 Glycerine, 31, 42 
 
 dinitrate. See Dinitroglycerine. 
 
 trinitrate. See Nitroglycerine. 
 Glycol, 28, 43 
 
 dinitrate. See Dinitroglycol. 
 Glucose nitrate. See Nitroglucose. 
 Gomme extraforte, 105 
 
 B, 105 
 
 3 B, 105 
 
 G, 105 
 
 Granulating, 2, 23, 82, 83 
 Graphite, 24, 72, 85 
 Greek Fire, 1 
 Grinding, 19 
 Grisounite couche, 141 
 
 roche, 128, 141 
 Grisoutite, 140 
 
 Guncotton, 2, 3, 45, 73, 193, 211, 221 
 Gunpowder, 1, 10, 11, 17-27, 118, 
 
 199, 210 
 Guttmann's test, 224 
 
 HEAT of explosion, 119, 197, 213 
 
 test, 11, 12, 208, 217-224 
 Hercules Powder, 97, 98 
 Herculite, 137 
 Herz, 147 
 
 Hexanitro benzene, 30 
 diphenyl, 63 
 
 amine, 30, 82, 63, 
 
 193, 210 
 oxide, 63 
 sulphide, 63 
 sulphone, 63 
 inosite, 29 
 mannitol, 28, 29, 62 
 oxanilide, 63 
 Holme's Buoys, 170, 177 
 
INDEX 
 
 " IENA " disaster, 81 
 Ignition, 213, 214 
 Imperial Schultze, 80 
 Impregnating, 163, 164 
 Incorporation, 20, 74, 214 
 Indurite, 82 
 Influence, 212 
 Initiators, 143-156 
 Inosite, 29 
 
 nitrate, 29 
 
 Instantaneous fuze, 158 
 Italian powders, 78 
 
 JELLYBAG mixer, 149 
 Judson Powder, 98 
 
 KENTITE, 132 
 Kiesselguhr, 93 
 Klepsydra, 204 
 Kohlencarbonite, 140 
 Kynarkite, 135 
 Kynoch's Smokeless, 86 
 
 LABYRINTHS, 37 
 
 Le Boulange Chronograph, 202-204 
 
 Le Chatelier, 201 
 
 Lead azide, 13, 28, 31, 143, 146, 147 
 
 block, 179-181 
 
 dioxide, 163 
 
 nitrate, 92, 175, 228 
 
 picrate, 147, 210 
 
 thiocyanate, 163 
 
 thiosulphate, 148 
 Leaders, 176 
 Liberti disaster, 81 
 Life-saving rocket, 175 
 Ligdyn, 98 
 Lighting buildings, 8 
 Liquid air, 4, 108 
 Low powder, 98 
 Lyddite, 6 
 
 MACARITE, 185, 193 
 
 Magazines, 7 
 
 Magnesium powder, 176, 177 
 
 sulphate, 120, 164 
 Mahieu Chronograph, 205 
 Mallard, 201 
 
 Manganese dioxide, 108, 163 
 Mannitol hexanitrate. See Hexa- 
 
 nitromannitol. 
 Manufactured Firework, Definition 
 
 of, 14 
 
 Marcel Chronograph, 204, 205 
 Maroons, 170 
 Match composition, 163-167 
 
 Match machines, 164, 165 
 
 Non-safety, 163 
 
 Quick, 158, 176 
 
 Safety, 163 
 
 Slow, 158, 175 
 
 Strike-anywhere, 163 
 
 Wait-a-minute, 164 
 Matches, 162-167 
 McNab, 6, 120 
 
 McRoberts machine, 100, 101 
 Mechanical shock, 208, 209, 216 
 Melinite, 6 
 Mercury chloride, 223 
 
 fulminate, 2, 13, 28, 31, 143- 
 
 146, 193, 199, 210 
 Mettegang, 186, 197 
 
 recorder, 186 
 Mica, 96 
 Milling, 20 
 
 Mineral jelly, 71, 73, 74 
 Minite, 140 
 Mixing explosives, 19 
 Moddite, 78, 79 
 Moir's test, 224 
 Monobel No. i, 134 
 Ai, 134 
 A2, 134 
 
 Mononitro. See under Nitro. 
 Mortar, 181 
 
 Moulded powders, 25, 67, 68 
 Moulding, 25 
 Mullerite, 87 
 Muzzle flame, 70 
 
 velocity, 202 
 
 NAPHTHA, 108 
 Nathan, 37, 45 
 Nationalite No. i, 132, 133 
 
 No. 2, 132, 133 
 Necrosis, 163 
 Neonal, 137 
 
 No. i, 137 
 Neu-Westfalit, 138 
 Nitrate Mixture, Definition of, 11 
 Nitrating-centrifuge, 48, 49 
 
 -house, 32, 37 
 Nitrator-separator, 37-39 
 Nitric acid recovery, 64, 65 
 Nitro acetin. See Dinitroacetyt 
 
 glycerine, 
 benzole, 82, 108 
 benzyl nitrate, 30 
 cellulose, 23, 43, 44, 70, 82, 
 211, 213, 221, 223. See 
 also Collodion ; Guncotton ; 
 Pyroxylin. 
 
 chlorhydrin. See Dinitrochlor- 
 hydrin. 
 
INDEX 
 
 239 
 
 Nitro compound, Definition of, 11 
 cotton. See Nitrocellulose, 
 diazobenzene nitrate, 30 
 diglycerine. See Tetranitro- 
 
 diglycerine. 
 
 formin. See Dinitroformin. 
 glucose, 29 
 glycerine, 2, 3, 12, 28, 29, 37- 
 
 41, 181, 191, 193, 199, 210, 
 
 213, 223 
 
 glycol. See Dinitroglycol. 
 lignine, 5, 85 
 mannitol. See Hexanitro- 
 
 mannitol. 
 
 methane, 29, 61, 62, 103 
 naphthalene, 109, 111 
 phenyl nitromethane, 30 
 starch, 29, 62 
 sucrose, 29 
 sugars, 29, 62 
 toluol, 53 
 Nobel, 3. 71, 195, 197 
 
 OCHRE, 93 
 Oleum, 32, 47, 53 
 Oxyliquit, 108 
 Ozonides, 31 
 
 PACKING, 126, 155 
 Paraffin, 109, 113 
 Pendulum, 182-184 
 Pentanitromethyl aniline, 61 
 Perchlorate explosives, 111-113, 137 
 Percussion cap, Definition of, 14 
 
 caps, 144-160 
 
 fuzes, 160 
 
 Permissible explosives, 10, 121, 123 
 Permitted explosives, 10, 121, 123 
 Permonite, 111, 195 
 
 S.G.P.,140 
 Pernitral, 112 
 Peroxides, 31 
 Peteval, 197 
 Phosphoric acid, 164 
 Phosphorus, 162, 163 
 
 Red, 163 
 
 Scarlet, 163, 166 
 
 sulphide, 163 
 
 White, 162, 163, 166 
 Phosy-iaw, 163 
 
 Photographic flash lights, 176, 177 
 Picric acid, 5, 6, 30, 58, 59, 185, 
 189, 190, 193, 211 
 
 anhydride, 63 
 Picryl chloride, 63, 193 
 
 sulphide, 63 
 Pitite No. 2, 135, 136 
 Polarite, 111 
 Porosity, 79 
 
 Potassium bichromate, 86, 87, 163 
 
 chlorate, 92, 106-113, 162-167, 
 230 
 
 chloride, 134 
 
 nitrate, 17, 18, 82-86, 92, 96- 
 141, 230 
 
 perchlorate, 92, 106, 107, 111- 
 
 113, 137, 230 
 Poudre B, 5, 71, 81 
 
 J, 86, 87 
 
 M, 86, 87 
 
 S, 86, 87 
 
 T, 86, 87 
 
 T bis, 87 
 
 Power of explosives, 178-184 
 Pressing caps, 152 
 
 cordite, 74-76 
 
 detonators, 154 
 
 gunpowder, 21 
 
 propellants, 74-76, 81 
 Pressure of explosion, 67, 195 
 Pre-washing, 36, 37 
 Products of explosion, 26, 27, 91 
 Promethee, 108 
 Propellants for rifled arms, 67-81 
 
 Gunpowder, 19, 25 
 
 Shot-gun, 82-87 
 
 Smokeless, 67-89 
 
 Nitrocellulose, 71, 72, 79-87, 
 223 
 
 Nitroglycerine, 70-79, 223 
 Pulping nitrocellulose, 51 
 Pyrophoric alloys, 168-170 
 Pyrotechny, 170-177 
 Pyroxylin, 50 
 
 QUICK-MATCH, 158, 176 
 
 RACK-A-ROCK, 4, 108 
 Randanite, 96 
 Recovery of acetone, 77 
 
 alcohol, 81, 84, 145 
 
 ether, 81, 84 
 
 nitric acid, 64, 65 
 
 sulphuric acid, 64-66 
 Rex Powder, 134 
 Rintoul, 37 
 Roburite No. 4, 132 
 Rockets, 170, 174, 175 
 Rodman gauge, 195 
 Rohrenpulver, 78 
 Roman candles, 170, 174 
 Rotherham test, 123-125 
 Rothweil Powder, 87 
 
 SABUMTE, 114 
 
 antigrisouteuse, 141 
 Safety, 7 
 
 explosives, 117-141 
 
240 
 
 INDEX 
 
 Safety fuze, 156 
 
 Definition of, 14 
 
 Nitro, 98 
 Saltpetre. See Potassium nitrate 
 
 and Sodium nitrate. 
 Samsonite No. 2, 132, 137 
 
 No. 3, 137 
 Sarrau, 197 
 Saxonia, 87 
 Schonbein, 2 
 Schultze Chronograph, 204, 205 
 
 Cube Powder, 86 
 
 Powder, 5, 85, 86 
 Sensitiveness, 207 
 Separating-house, 34 
 Separation, 34, 35, 37 
 Shaking test, 214 
 Shell fuzes, 159, 160 
 Shells, Pyrotechnic, 171 
 Shot-gun propellants, 82-87 
 Silesia No. 4, 111 
 Silica, 35, 96 
 Silk, Artificial, 46 
 Silvered vessel test, 224, 225 
 Slow-match, 158, 175 
 Smokeless Diamond, 85 
 
 propellants, 67-89 
 Sobrero, 2 
 Sodamide, 146 
 Sodium azide, 146 
 
 chlorate, 92, 106, 109-111 
 
 chloride, 11, 12, 132-134 
 
 fluoride, 35 
 
 nitrate, 11, 12, 92 
 powders, 17, 25 
 
 perchlorate, 92 
 
 phosphate, 164 
 
 tungstate, 164 
 Solenite, 78 
 Solvents, 87 
 
 Specific heats of gases, 201 
 Spent acid. See Waste acid. 
 Spica's test, 224 
 Sporting Ballistite, 86 
 
 propellants, 67-86 
 Sprengel explosives, 4, 5, 108, 109 
 Sprengsalpeter, 25 
 Squibs, 171, 173 
 Stability, 207 
 Stabilizers, 70, 233 
 Stamp mills, 20 
 Stanford Powder, 131 
 Star shell, 172, 173 
 Starch nitrates, 29, 62 
 Stars, Pyrotechnic, 170, 172, 173 
 Statistics, 9 
 Steelite, 111 
 Stomonal No. i, 134 
 
 No. 2, 134 
 
 Stonite, 98 
 Stoving, 24 
 Straight Dynamite, 97, 122, 191, 
 
 192, 215 
 Street, 5 
 
 Stump Powder, 98 
 Sucrose nitrate. See Nitrosucrose. 
 Sulphur, 18 
 Sunderite, 131 
 Super-Curtisite, 132 
 
 -Excellite, 134 
 
 No. 2, 126, 134 
 
 -Kolax, 135 
 No. 2, 135 
 
 -Rippite, 6, 136, 137 
 Swale Powder, 137 
 
 TEMPERATURE of explosion, 200, 201 
 
 ignition, 213 
 Tetranitro aniline, 6, 30, 59 
 
 diglycerine, 28, 40, 103 
 
 methane, 29, 62 
 
 methyl aniline, 6, 30, 60, 185, 
 193, 210, 233 
 
 methyl phenyl nitramine, 61 
 
 naphthalene, 30, 231 
 
 toluol, 30 
 
 Tetryl. See Tetranitromethyl ani- 
 line. 
 
 Thames Powder No. 2, 134 
 Thawing explosives, 90 
 Thiophosphites, 167 
 Thomson, 37, 45 
 Thunderite, 118, 195, 199 
 Tiger Powder, 87 
 Time fuzes, 160 
 
 recorder, 186 
 Tin thiocyanate, 163 
 Tipping matches, 164, 165 
 Tonite, 115 
 Touch paper, 175 
 Trauzl test, 179-181 
 Tremonite S. II., 139 
 Trinitro benzole, 30, 193, 231, 233 
 
 chlorbenzole. See Picryl chlo- 
 ride. 
 
 cresol, 30, 193 
 
 naphthalene, 30, 210, 231 
 
 phenol. See Picric acid. 
 
 phenyl methyl nitramine, 30, 
 
 60, 185, 193 
 nitromethane, 30 
 
 toluol, 6, 30, 52-58, 85, 99, 
 103, 158, 159, 185, 189, 190, 
 193, 194, 210, 211, 231 
 
 xylol, 30 
 
 Triolite. See Trinitrotoluol. 
 Triplex Safety Glass, 149, 151 
 Tritol. See Trinitrotoluol. 
 
INDEX 
 
 241 
 
 Trotyl. See Trinitrotoluol. 
 Tubular powders, 74 
 Turpentine, 108 
 Tutol No. 2, 131 
 
 UNITED States Military Powder, 
 79-81 
 
 VARNISHING caps, 152 
 Vaseline. See Mineral jelly. 
 Velocity of detonation, 109, 110, 
 
 118, 185-195, 212, 213 
 Very Stars, 170 
 Victor Powder, 132, 134, 135 
 
 No. 2, 134, 135 
 Vieille, 5, 71 
 test, 224 
 Viking Powder No. I, 134 
 
 No. 2, 134, 135 
 Violence. See Brisance. 
 Viscosity, 49 
 Volkmann, 5 
 von Lenk, 2 
 Vulcan Powder, 98 
 
 WALSRODE Powder, 87 
 Waltham Abbey Silvered Vessel 
 Test, 224, 225 
 
 Warming pans, 90 
 Wash house, 35, 36 
 
 waters, 37, 145 
 Washing nitrocellulose, 50-52 
 
 nitroglycerine, 35, 36 
 Waste acid, 34, 37, 47, 55, 64-66 
 Waterproofing cartridges, 127 
 Werner and Pfleiderer Machine, 74, 
 
 75, 80, 94, 100 
 Westialite No. 3, 133 
 
 fur Kohle, 113 
 Wetter-Dynamit, 194 
 
 Dynammon, 139 
 
 Fulmenit, 138 
 
 Wettersichere Sprengstoffe, 121, 138 
 Whistling fireworks, 174 
 Will test, 225 
 Wood, Carbonization of, 18 
 
 Nitration of, 85, 86 
 Wrappers, 91, 127-129, 136 
 Wiirfelpulver, 78 
 
 YONCKITE, 112 
 
 10 bis, 140 
 
 ZINC sulphate, 164 
 sulphide, 163 
 thiophosphate, 167 
 
 Printed by William Clowes & Sons, Limited, Beccles, for BaiUiere. Tindall & Cox, 
 8, Henrietta Strtet, Covent Garden, W.C. 2. 
 
 T. 
 
 16 
 
INDUSTRIAL CHEMISTRY 
 
 Being a Series of Volumes Giving a Comprehensive Survey of 
 
 THE CHEMICAL INDUSTRIES 
 
 Edited by SAMUEL RIDEAL, D.Sc. (Lond.), F. I. C, Fellow of 
 University College, London. 
 
 NOW READY 
 Coal Tar Dyes and Inter- 
 mediates E. DE BARRY BARNETT, B.Sc., A.I.C. 
 
 PP. xviii + 214. pri^ $3.50 
 
 Explosives E. DE BARRY BARNETT, B.Sc., A.I.C. 
 
 Pp. xvi + 241, with 33 figs, price, $5.00 
 
 Plant Products and Chemical 
 
 Fertilisers S. H. COLLINS, M.Sc., F.I.C. 
 
 PP. xvi + 236. p rice> $3.00 
 
 The Industrial Gases . . . H. C. GREENWOOD, D.Sc. (Manchester). 
 
 PP. xxii + 371. Price, $5.00 
 The Alkali Industry . . . J. R. PARTINGTON, D.Sc. (Viet.). 
 
 Pp. xvi + 304, with 63 figs. Price, $3.00 
 
 Industrial Electrometallurgy E. K. RIDEAL, M.A. (Cantab.), PH.D., 
 
 F.I.C. 
 
 Pp. xii + 248, with 26 figs. Price, $3.00 
 
 The Application of the Coal 
 
 Tar Dyestuffs .... CM. WHITTAKER, B.Sc. 
 
 PP. xii + 214. p r ice, $3.00 
 
 IN THE PRESS 
 
 Animal Proteids . . . . H. G. BENNETT, M.Sc. (Leeds). 
 The Carbohydrates . . . S. RIDEAL, D.Sc. (Lond.), F.I.C., and 
 
 Associates. 
 IN PREPARATION 
 
 Fats, Waxes & Essential Oils W. H. SIMMONS, B.Sc. (Lond.), F.I.C. 
 Silica and the Silicates . . J. A. AUDLEY, B.Sc. (Lond.), F.I.C. 
 The Rare Earths and Metals E. K. RIDEAL, M.A. (Cantab.), PH.D., 
 
 F.I.C. 
 The Iron Industry .... A. E. PRATT, B.Sc. (Lond.), Assoc. 
 
 R.S.M. 
 The Steel Industry . . . A. E. PRATT, B.Sc. (Lond.), Assoc. 
 
 R.S.M. 
 
 Gas-Works Products . . . H. H. GRAY, B.Sc. 
 Organic Medicinal Chemicals M. BARROWCLIFF, F.I.C., and F. H. CARR, 
 
 F.I.C 
 
 The Petroleum Industry . . D. A. SUTHERLAND, F.I.C. 
 Wood and Cellulose . . . R. W. SINDALL, F.C.S., and W. BACON, 
 
 B.Sc., F.I.C., F.C.S. 
 Rubber, Resins, Paints and 
 Varnishes R. S. MORRELL, M.A,, Ph.D.; A. E. 
 
 WAELE, and the Editor. 
 Economic Fuel Production in Chemical Industry HUGH S. TAYLOR, D.Sc. 
 
RETURN TO: 
 
 CIRCULATION DEPARTMENT 
 198 Main Stacks 
 
 LOAN PERIOD 1 
 Home Use 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 ALL BOOKS MAY BE RECALLED AFTER 7 DAYS. 
 
 Renewals and Recharges may be made 4 days prior to the due date. 
 Books may be renewed by calling 642-3405. 
 
 DUE AS STAMPED BELOW. 
 
 IAN 2 R 2006 
 
 
 
 JMIN a 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 FORM NO. DD6 UNIVERSITY OF CALIFORNIA, BERKELEY 
 50M 1-05 Berkeley, California 94720-6000 
 
 LD 21A-50?n-3, T 62 
 (C7097slO)476B 
 
 University of California 
 Berkeley 
 
YC 70266