Manchester Memoirs, Vol. xlvi. (1901), No. 5. 



V. On the Measurement of High-Pressure 

 Explosions. 



By J. E. Petavel, 



Harling Felloiv of the Oivens College, Manchester. 



Received and read November 26th, igor. 



The study of the phenomena which take place during- 

 an explosion is of considerable importance both from a 

 theoretical and practical point of view. An exact know- 

 ledge of the variation of pressure will provide information 

 on the rate of cooling of gases under high pressures, on the 

 variation of specific heat at high temperatures, and on the 

 question of dissociation. 



From a practical point of view, such information is 

 needed in the design of modern artillery and in all 

 problems connected with ballistics. It enables the civil 

 engineer to select the explosive suitable for the purpose 

 to be attained. It guides the mechanical engineer in the 

 design of the heat engine. 



It is impossible in the present paper to do more than 

 enumerate the principal devices which have been used for 

 the measurement of explosive pressures. The first syste- 

 matic experiments were carried out by Robins in 1743, 

 Hutton in 1778, and Count Rumford in 1797. Rumford's 

 method consisted in determining the minimum weight 

 required to prevent a valve from lifting under the pressure 

 of the explosion, and was used with slight variations by 

 a long succession of investigators, the best known experi- 

 ments being those carried on by Bunsen in 1867. 



February loth, igo2. 



