1921] on War Development of Explosives 359 



country led the way in the technique and safety precautions involved 

 in the manufacture of propellants. The existing factories were also 

 capable of extension, until the demand became so great tbat additional 

 ones had to be erected. 



At first, the propellant used was cordite M.D., composed of 

 nitroglycerine, guncotton, and mineral jelly, in which acetone was 

 used to gelatinise the guncotton. A nitrocellulose powder obtained 

 from America was also used. The demamd for propellant to be 

 made in this country ultimately reached 1500 tons a week, and this, 

 even with an efficient system of acetone recovery, would have 

 involved an expenditure of that solvent of about 400 tons a week. 

 On account of the shortage of supply of this solvent, a new propellant 

 for the Land Service was introduced — cordite R.D.B. — in which 

 ether-alcohol was substituted for acetone as a solvent, a change 

 necessitating the choice of a nitrocellulose of a lower degree of 

 nitration than guncotton, and alterations in the proportions of the 

 other ingredients. For the new propellaut the conditions were laid 

 down, and met, that it should have the same heat energy, that it 

 should give the same ballistics as cordite M.D., in order to avoid 

 alteration in calculating ranges from data obtained with the older 

 propellant, and that it should be capable of being manufactured by 

 the machinery available and with the technique of manufacture 

 known in the country. 



The main changes introduced were in the manufacture of the 

 nitrocellulose and in the supply of the solvent. As ether-alcohol is 

 a less powerful solvent than acetone, even for the special nitrocellulose 

 employed, a strict definition of the nitrocellulose was necessary, and 

 the necessity to provide this in suitable form led to much investiga- 

 tive work on the nature of the cellulose, with the result that its 

 manufacture was brought under a system of strict chemical control. 

 This control had among its objects the elimination of ligneous 

 impurities and the standardisation of the viscosity of the cellulose, 

 since if its viscosity was uniform and low, it was found that the 

 gelatinisation of the nitrocellulose when incorporated with the nitro- 

 glycerine and mineral jelly was greatly facilitated, and the production 

 of uniform cords assisted. Ligneous matter in the cellulose was 

 rendered visible by a process in which the woody matter was dyed selec- 

 tively, and the viscosity of the cellulose was measured by the rate of 

 fall of a steel sphere falling through a solution of cellulose. 



The supply of alcohol was obtained entirely from the distilleries 

 of this country, and a large plant for converting a portion of it into 

 ether was erected at Gretna. Xearly 1000 tons of alcohol, or the 

 equivalent of about 200,000 gallons of proof spirit, were required 

 for the production of the 1500 tons of R.D.B. cordite a week, and 

 it was this requirement which led to the restricted sale and increased 

 cost of whisky. 



