122 



30 



APPENDIX 8 RESUME OF RAMSAUSR'3 EXPERIMSNTS 



In the experiments of Ramsauer mentioned In the Intro- 

 rJuctlon, the objective was to obtain measurements of the radius-time 

 curve for the first expansion of the bubble. Ramsauer worked with 

 charges of one or two klograms of guncotton at depths up to 9 

 meters, at a place where the total depth of water was 12 meters. 

 The charge was suspended near a submerged Iron framework which 

 carried a number of rigid electrodes. Electrolytic currents 

 flowed to each of these electrodes fron a single electrode 

 some distance away. When the expanding gas bubble from the explo- 

 sion reached any particular electrode, that electrode became iso- 

 lated from the water and the current in the circuit to which it 

 was connected ceased. Measurement of the time of cessation of 

 the current in the circuit of each electrode thus gave a point 

 on the radius- time curve of the bubble. Only the expanding 

 phase of the motion was studied, and the difficulty of supporting 

 electrodes rigidly close to the explosion prevented measurements 

 from being taken at less than about a quarter of the maximum 

 radius. 



Ramsauer found the variation of a^g^^ with depth and 

 charge of explosive to agree nicely with the prediction W r 

 -^irRo^max °^ ^^^ simple theory, with W ~ 0.41Q. This is in 

 fair agreement with values of W/Q found in recent work for 

 other high explosives. He also attempted to check the energy 



equation (5) by using his measured values of da and some calculated 



dt 



"50 



^C. Ramsauer, Ann. d. Physlk 72, P65 (1923) 



