GUN-COTTON 



46T 



keeps the nitric acid up to its full 

 Schonlx'in's discovery gave a great impetus to the 

 |tieMioii, iiinl experiments continued to be made 

 l>v many eminent chemists in nearly every country 

 .H.'|>e with the idea of utilising the new explo- 

 ior military purjKwes. It was first manu- 

 factured in England <>n a large scale in the year 

 1st; liy Messrs Hall & Son of Faversham ; but, in 

 addition to minor accidents, a terrible explosion 

 took, place in the.ir works, which created so much 

 distrust that its manufacture in England was dis- 

 continued for several years, as the cause of the 

 explosion, with llie then imperfect knowledge 

 possessed of the siiliject, could not lie satisfactoril y 

 acconnte.l for. The first country to turn Schon- 

 liein's discovery to practical account was Austria. 

 (Jeneral Von Lenk, an Austrian artillery officer, 

 after extensive trials succeeded in greatly improv- 

 ing the method of manufacture, by which means he 

 was enabled to moderate and ensure a uniform rate 

 of combustion of gun-cotton in air ; his discovery 

 was considered of so much importance that in the 

 year 1852 several batteries of Austrian artillery 

 were armed with gun-cotton cartridges. But it 

 soon fell into disrepute, not only on account of its 

 unstable nature, but also because it was found that 

 Von Lenk's improvements were of no practical 

 utility when the gun-cotton was confined in the 

 bore of a gun ; the great heat generated caused the 

 inflamed gas to penetrate rapidly through the 

 whole, cartridge, so that there was little or no re- 

 tardation in the rate of combustion, and the rapid 

 combustion caused excessive pressure in the bore, 

 besides giving very unequal results when fired. 



Since the failure of the Austrian cartridges gun- 

 cotton has not been used as a propelling agent on a 

 large scale. But its utility as a disruptive agent 

 has been enormously increased by the discoveries 

 of Professor Sir Frederick Abel and the late Mr 

 E. O. Brown. Nothing daunted by the failure of 

 the Austrian experiments, nor by the explosion at 

 Messrs Hall's works, Sir Frederick Abel continued 

 his experiments, and he ultimately discovered a 

 method of manufacture whereby not only a com- 

 plete purification from free acid is assured, but 

 the material is converted into thoroughly compact 

 homogeneous masses. As a result of his experi- 

 ments the method of manufacture adopted in 

 England may be briefly described as follows : the 

 best white cotton waste alone is employed ; this is 

 first thoroughly cleansed from all grease by boiling 

 with alkalies ; it is then picked over by hand and all 

 foreign substances removed, after which the fibre 

 is separated and all knots and lumps opened out 

 by passing the cotton waste through a 'teasing' 

 machine ; it is then cut into 2-inch lengths, 

 thoroughly dried, and divided into charges weigh- 

 ing 1J Ib. each, which are kept in air-tight tin 

 boxes till ready for dipping. The acids used in the 

 manufacture of gun-cotton are nitric acid having 

 a specific gravity of 1 -52 and sulphuric acid of 1 '84 

 sp. gr. ; these are mixed in the proportion of one 

 part by weight of nitric acid to three of sulphuric 

 acid, and allowed to cool down in iron tanks. The 

 mixed acid is run off into the dipping pans into 

 which a IJ-lb. charge of cotton is immersed and 

 left in for about five minutes, in which time it will 

 have absorl>ed about 14 Ib. of acid. The charge is 

 now allowed to cool down, after which the waste 

 acid is extracted by means of an ' acid-extractor,' 

 and the charge thoroughly washed to remove all 

 the free acid. It is now pulped and pressed under 

 hydraulic presses to one-tnird its bulk, and moulded 

 into slabs of various sizes and shapes for storing. 

 The method of manufacture as here described is 

 perfectly safe, as the gun-cotton throughout is in a 

 wet state. 

 The properties of gun-cotton, as compared with 



gunpowder, are mainly aa follows : ( 1 ) It can be 

 ignited at a temperature of about 900, whereat 

 gunpowder requires a temperature of about 600* 

 to ensure ignition ; (2) its combustion leaves no 

 solid residue, and in unattended by smoke; (3) 

 the action of gun-cotton is much more rapid than 

 that of gunpowder, and, as has already been 

 pointed out, it is this rapidity of combustion which 

 renders it unsuitable to be used as a propelling 

 agent in cannon ; (4) whereas gunpowder is greatly 

 influenced and injuriously affected by moisture, 

 gun-cotton on the contrary is perfectly uninjured, 

 and may be kept for any length of time in water 

 without change. For military purposes this is a 

 most important consideration. Apart from the 

 question of using gun-cotton as a propelling agent, 

 its value for destructive purposes was incontest-* 

 able, but it was thought to be necessary, in order 

 to develop its full j>ower, that the charge should 

 be strongly confined. Experiments, however, con- 

 ducted by Mr E. O. Brown clearly demonstrated the 

 fact that compressed gun-cotton could be fully de- 

 tonated in a totally unconfined state by fulminate 

 of mercury. This discovery was thought to apply 

 to dry gun-cotton only, but Mr Brown continuing 

 his experiments ascertained that wet compressed 

 gun-cotton could be detonated by using a small 

 primer of the dry material. Still further dis- 

 coveries were made with regard to the detonation 

 of gun-cotton ; it was ascertained that detonation, 

 being established at one end of a continuous row of 

 distinct masses of compressed gun-cotton, travels 

 along the whole length of the row, even if a space 

 of half an inch is left between the discs. These 

 discoveries have raised gun-cotton to the highest 

 rank as a military explosive, as the necessity for 

 storing it in a dry state, which is so highly danger- 

 ous, is entirely obviated ; it is now always stored 

 in a wet state, the gun-cotton containing about 20 

 per cent, of water, and is packed in air-tight metal 

 cases, so that the necessity for rewetting seldom 

 occurs ; in this condition it can be transported with 

 perfect safety. 



The discovery with regard to its detonation when 

 in a wet state has led to this material being used 

 as the charge for torpedoes and submarine mines. 

 The first pattern of Whitehead torpedo was 14 feet 

 long and 16 inches in diameter ; the speed of the 

 torpedo was 9 knots for 200 yards, and the 

 charge was 118 Ib. of compressed wet gun-cotton. 

 Several subsequent patterns of torpedoes have been 

 introduced, the latest being 14 feet long and 14 

 inches in diameter, and by reducing the charge of 

 gun-cotton to 80 Ib. the high speed of 27 knots for 

 600 yards has been attained. The immense im- 

 portanqe of this increased speed can be readily 

 appreciated, as it enables a torpedo to strike the 

 vessel at which it is discharged before she has time 

 to get out of the way. The torpedoes are fired by 

 a striker actuated by a spring which is released on 

 the torpedo striking the side of the ship ; the 

 striker is pointed, and penetrates a cap charged 

 with 38 grains of fulminate ; this cap is embedded 

 in an 8 oz. disc of dry gun-cotton, enclosed in a 

 hermetically sealed case, and placed as nearly as 

 possible in the centre of the wet gnn-cotton charge 

 containing 12 per cent, of water. Gun-cotton is 

 also used as the charge for submarine mines, the 

 charge consisting of from 50 to 500 Ib. of wet com- 

 pressed gun-cotton. 



There are various descriptions of marine mines. 

 ( 1 ) Ground mines: in these the charge is contained in 

 a case of sheet steel, with cast-iron sinkers attached 

 to it to keep it at the bottom of the harl>our or 

 river ; these mines are fired electrically by observa- 

 tion from the shore when an enemy's ship passes 

 over them. ( 2 ) Buoyant mines : these are anchored 

 a few feet below the surface of the water by a steel 



