144 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1917. 



geneous. Charges are thus obtained which are free from piping. It 

 is this valuable property which justifies the use of the nitrocresols in 

 charging projectiles. 



In spite of the fact that cresylite 60/40 has less force (8,380) 

 than picric acid, its rate of detonation (7,485 meters per second) is 

 practically the same as the latter. 



Like the trinitrophenol the trinitrocresol has an acid function. 

 It forms salts analogous to the picrates and these are explosive. 

 The ammonium cresylate only is sufficiently insensitive to shock to 

 permit of its military use. In Austria it has been used in charging 

 shell under the name of ecrasite and its power, though inferior 

 to that of melinite or cresylite, is superior to that of dynamite No. 1. 



4. Trinitronaphthalene or naphtite (C 10 H G (NO 2 ) 3 ). — Trinitro- 

 naphthalene is a clear yellow substance which is only slightly soluble 

 in water, but is soluble in acetic acid and chloroform. Its sensitive- 

 ness to shock is very much less than that of melinite but it re- 

 quires a very powerful detonator with which to effect its detonation. 

 When ignited it burns, without explosions, with a smoky flame, and 

 it resists the shock of impact of small-arm projectiles. 



It is prepared by nitrating the mononitro or clinitronaphthalcnes 

 as a mixture of three isomeric trinitronaphthalenes which fuse 

 about 110°. 



At present naphtite is but little used as shell charges because of 

 the difficulty of detonating it as mentioned above. It, however, is 

 a powerful explosive, which, exploded in a bomb under the density 

 of loading of A =0.3, gives a pressure of 3,275 kilograms per square 

 centimeter. 



5. Favier explosives and schmeiderite. — The Favier explosives have 

 an ammonium nitrate base to which a slightly nitrated hydrocarbon 

 (which is therefore but slightly explosive) is added. The ammonium 

 nitrate itself being an explosive which is quite insensitive, the mix- 

 ture obtained is remarkably insensitive, but its ignition temperature is 

 relatively quite low. This union of properties explains its employ- 

 ment in coal mines as a safety explosive. The mixture of ammonium 

 nitrate 90 per cent with mononitronaphthalene 10 per cent, con- 

 stitutes schneiderite employed at Creusot for filling shell. It is a 

 powerful explosive which is characterized b}^ a force of 8,400 units 

 and a potential of 415 ton meters. Its normal rate of detonation, as 

 determined by M. Dautriche, was 3,585 meters per second for the 

 pulverulent explosive. 



It has been said above that Favier explosives are but very slightly 

 sensitive to shock and thus schneiderite has been found to resist the 

 impact of a projectile or the blow from a very heavy weight and, 

 when placed on the rail, a cartridge of this substance was not ex- 



