1915] 



on Gaseous Explosions 



297 



proper time, and the charge is compressed, ignited and dealt with as 

 required experimentally. Knowing the charge temperature in this 

 way, it is possible to calculate with considerable accuracy the 

 temperatures at the four points. In this method there is no compli- 



Fig. 24. 



cation due to hot gases being left in the cylinder ; the temperature of 



the whole charge which is used for experimenting is measured by 



repeatedly passing over the thermometer. Temperatures have been 



I calculated of the points A, B, C, and D in this manner, and Fig. 25 



Fig. 25. 



shows a diagram taken by an optical indicator with all the neces- 

 sary data. It will be seen that the temperatures are 20° C, 214° C, 

 1380° C, and 651° C. This method gives good results, but is only 

 available where single charges are studied. It, however, allows of 



