561 



Th« raaulting period constant, K^ - 5.065, may b* compared with the 

 value 5.10, obtained by Bord»n and Arena (references indicated under the 

 discusiion of TNT). 



Uore recently a series of 280 gm torpex-2 charges fired at this 

 laboratory within 5 ft of the surface gives an average value of 5,08 for K], 

 after correcting for the effects of surfaces^. 



TABLE II 

 FIHST PERIOD CONSTANTS FOR TORPEX-2 IN FREE WATER*** 



* Depth from meter wheel 



** Period calculated from film 



***See Ref. 25 for composition of torpex-2. 



Table HI gives the results obtained for 1/2 lb pressed tetryl charges, 

 density 1.5, in free water. The shots labelled "GO" were recorded when 

 the charge was in the vicinity of a small steel cylinder^); however, a 

 critical comparison of these shots with the rest showed no systematic 

 discrepancy. This seems reasonable because of the relatively small size 

 of the cylinder, OccasionEuLly a large discrepancy in the period appeared, 

 as in shot GG4OE iriiere the deviation from the mean is about 30^*. Thia 

 error was occasioned by the electronic gear, and was not a scatter in the 

 property being measured, as indirect evidence from the collapse of the 

 cylinder, discussed in Ref, (9), shows the period to be actually about 

 20 msec in this case, resulting in a period constant consistent with the 

 other values. 



An entirely independent series of shots ia shown in Table IV. These 

 were carried out with a different set of equipment and in water sufficiently 



* See also G21F in Table I, 



■5- 



