PROJECTILES CONTAINING EXPLOSIVES A, R. 145 



plocled by the passage of a train. These properties imply the neces- 

 sity of using a very powerful detonator with which to provoke its 

 detonation. 



6. Benzite (C 6 H 3 (N0 2 ) 3 ). — Benzite or trinitrobenzene is a white 

 crystalline body which, when pure, fuses at 121°-122°. Although as 

 powerful as melinite x it is very- much less sensitive to shock than 

 the latter. Moreover, it does not attack metals and, when compressed, 

 it acquires a density of 1.67. Finally its rate of detonation, of the 

 order of 7,000 meters per second, is equal to that of picric acid. 



Trinitrobenzene is an extremely interesting body because of its 

 various properties. Unfortunately its price is so high as to limit 

 its use. Thus far it has not been employed except to lower the melt- 

 ing point and increase the plasticity of tolite. 



It is prepared by oxidizing trinitrotoluene with potassium di- 

 chromate in sulphuric acid solution by which trinitrobenzoic acid 

 is formed, and this on treatment with boiling water splits off the 

 C0 2 group yielding the trinitrobenzene. The chrome alum formed, 

 and which remains in the sulphuric acid liquor, is recovered by con- 

 centration and crystallization and is again converted into the di- 

 chromate. 



7. Nitro derivatives of aniline. — Aniline (C 6 H_NH 2 ) is capable 

 of furnishing a series of explosives that may be employed in charg- 

 ing projectiles. We will examine some of the more interesting of 

 them. 



The tetranitraniline appears as a crystalline body very similar 

 to picric acid. It is prepared by heating the metanitraniline at 80° 

 with concentrated mixed acids. It is an extremely powerful explo- 

 sive, very stable and contains 25.6 per cent of nitrogen. Its abso- 

 lute density, 1.867, is relatively very high. It is partially decom- 

 posed on heating at a temperature which depends on the manner 

 in which the increase in temperature in a given time has been effected. 

 Thus, if the rate of increase is 5° per minute the decomposition be- 

 gins at 216°-217°. This does not give rise to explosion. While in- 

 soluble in water at ordinary temperatures, it is very soluble in ace- 

 tone. It does not attack metals. By reason of this assemblage of 

 properties tetranitraniline appears to be most advantageous for use. 



Another nitro derivative of aniline which is equally interesting 

 from our standpoint is tetryl. This body which is tetranitromethyl- 

 aniline (C 6 H 2 (N0 2 ) 3 NN0 2 CH 3 ) contains 24.2 per cent of nitrogen. 

 More powerful than guncotton or melinite it is less so than tetra- 

 nitraniline. According to Lieutenant Colonel Koehler its heat of 



1 According to M. Dautriche, the power of benzite is 5 per cent greater than that of 

 picric acid. 



