Show recording of a second according to one of tho government scientists in experimenting with high power explosives used in guns a chronoscope has been employed which registered the velocity of the projectile at 16 successive points before it left the bore it was possible with this apparatus to register time to the millionth of a second in former experiments where the velocity did not exceed 1500 or 1600 feet a second the projectile recorded its time by knocking down a series of cheel triggers projecting into the bore but with velocities of 2500 feet and more to the second the trigger in stead of dropping frequently plowed a groove in the projectile and adoth er device was necessary |