560 



Two other valuee have been obttiined vmder carefully controlled con- 

 dition*. Slichter, Schneider, aaid Cole^) report a value of A. 36 for 

 295 lb TNT charges in relatively shallow water, after correcting their 

 period meaaurements for the effects of surfaces?), Borden and Arons^; 

 have similarly corrected the period values for l/2 lb charges in shallow 

 water foimd by Arona, Borden, and Stiller?) and from their resvilts the 

 constant appears to be 4»32. These authors, however, ha've assumed a 

 slightly higher energy factor for the tstryl booster. If the factor of 

 1,03 used in this report is applied to their data, their' TNT period 

 constant becomes 4*35« Other values may be found in Table X. 



TABLE I 

 FIRST PERIOD CONSTANTS FOR CAST TNT IN FREE WATER 



* Period from pictures agrees to + 2%, 



** Period from pictures — no piezoelectric record, 



Table II presents the data obtained for torpex-2 charges. The depth 

 measurement in this case is perhaps slightly less reliable than for the TNT, 

 since it was found from meter wheel readings alone in four of the eight 

 shots. Three of the eight periods were read from radius-time curves made 

 from the pictures. Since in the other five cases the difference between 

 this period and the electronic r.easiu-ement was at worst 1.3^, this may be 

 considered sufficiently good. The booster correction was made by multi- 

 plying the weight of tetryl (44 gm) by 0.65. 



