VI. Inwutiijdtion of the IAIW of llwning of Modified ('onlite. 



liij Major J. H. MANSELL, Royal Artillery. 

 Communicated In/ Sir A. NOBLE, F.R.S. 



Received November 9, 1906, Read February 14, 1907. 



CONTENTS. 



fegl 



Introduction 243 



Desoi'iption of apparatus 244 



Characteristics of the explosive : 



1. Relation of pressure and density 246 



2. The time rise of pressure, cord form 249 



3. Reconciliation of the law of reduction 251 



4. The time rise of pressure, tube form .251 



5. The time rise of pressure, double tubular form 257 



Conclusion 257 



Tables (A-D) 259-262 



SOME years ago the eminent French chemist VIEILLE first propounded the law of 

 combustion by parallel surfaces for smokeless pro|>ellaiits. By a propellant we 

 distinguish an explosive which explodes .from one that detonates ; and it is this 

 combustion by parallel surfaces which is the distinguishing characteristic of the 

 difference of the two phenomena. 



Since VIEILLE first propounded his theory it has l)een generally accepted as correct. 

 Investigators, however, have not, so far as I am aware, definitely determined what 

 the law is. The general assumption has been that the law is of the form S = aP", 

 where S is the skin burnt in a given time under the average pressure P, and ?i 

 l>eing constants for the given explosive. 



Now, the investigators who have dealt with this subject have all done so with the 

 primary object of finding out what goes on inside a gun when the charge is fired. 

 That has also been my primary object. In fact, it is the practical as distinguished 

 from tin- pun-lv scientific result of the law which has appealed to all investigators. 



Now, the gun is a most complex L, r as engine, and in the past has upset the most 

 carefully conceived and elalxjrated theories. Previous investigators have therefore 



VOL. own. A 4 IS. 2 I '2 31.5.07 



