358 MR. J. E. PETAVEL ON THE PRESSURE OF EXPLOSIONS. 



LIST OF FIGURES. 



No. 



1. Maximum pressure gauge . . . 



Recording manometer diagram . . . 



3. Recording manometer drawing . 363 



4. Chronograph camera 



5. Spherical explosion chamber 366 



6. Cylindrical explosion chamber 368 



7. Firing plug 



s. Valve and cone connections 370 



9. Effect of ignition by oxyhydrogen and by gunpowder compared ... . . 372 



10. Typical time pressure curve resulting from the explosion of cordite in a closed vessel . . . 373 



11. Variation of rate of explosion with the size of cordite used, gravimetric density 0- 10 . . . 374 



12. Variation of rate of explosion with the size of cordite used, gravimetric density 0-15. . . 375 



1 3. Effect of the gravimetric density and the diameter of the explosive on the time required to 



reach the maximum pressure 375 



1 4. Rate of rise of pressure for cordite of the smallest diameter 377 



15. Effect of the shape of the enclosure on the maximum pressure developed by cordite of large 



diameter 380 



16. Effect of the dimensions of the enclosure on the rate of cooling of the products of 



combustion 381 



17. Variation of maximum pressure with gravimetric density .... 384 



18. Diagram illustrating the action of the explosion wave which is set up when the explosive 



is unevenly distributed 386 



19. Variation in the rate of combustion and maximum pressure produced by a non-uniform 



distribution of the charge for cordite of 0-475 inch diameter 389 



20. Variation in the rate of combustion and maximum pressure produced by a non-uniform 



distribution of the charge for cordite of 0' 175 inch diameter 389 



INTRODUCTION. 



THE scientific treatment of this question may be said to date from the researches of 

 Count RUMFORD who, at the end of the eighteenth century, devised the first 

 apparatus by which explosive pressures could be estimated with some degree of 

 approximation. 



During the past century the natural fascination of the subject, and the importance 

 of the problems involved, attracted many of the ablest scientific minds. Several have 

 made the study of explosions the object of their life work. 



In the short space available, an adequate historical epitome is unfortunately 

 impossible. A mere enumeration of the names with which we shall most frequently 

 have to deal must therefore suffice. 



Our knowledge of the behaviour of solid explosives is due principally to the 

 brilliant work of NOBLE in this country, and of BERTH ELOT and VIEILLE abroad. 

 With regard to explosive gaseous mixtures, the exhaustive work of LE CHATELIEB 

 and MALLARD in Paris, of DIXON in Manchester, and CLERK in London, is familiar 

 to all. 



