606 - ^ - 



instedO of orsakinj off continuously in indefinitely thin layers woula not br^ak imeaiately but 

 the first layer would havr a finite but snail thickness. Thus taking the 300 lb. depth charge 

 at 50 feet, if °= 0.2 tons cer square inch the thickness of this layer would probably be about 

 6 cms. and the corrected maxiraum or^ssure would be 0.1 tons more. At present, however, this is 

 quite gpeculativo. 



As already statea an ipo-^ratus for the direct recording of the time oressure sequence is 

 being constructed in Mining School. 



Experiments tc this rnvc b'.on in ;r;;i;ress elsewhere. 3: far as is unown these are:- 



(1) Hookinson's "ressure Bar method in use at Woolwich Arsenal, 



(2) Hillier's experiments at Troon by means of crusher gauges. 



(3) A method devised by Sir j.j. Thomson which makes use of the oiezo electric prooertles 

 of quartz. 



It is hoped that in course of time the different methods may be compared, as the problem is 

 such a difficult and delicate one that it would be most unwise t; trust t: any one method entirely 

 until satisfactory agreement jf two indapendsnt methods can be established.. 



