APPENDIX. 547 



1 to 1'2, contained in leaden tubes 4 mm. external diameter, and 

 about 100 m. in length, the average velocity varied from 



4952 m. 9500 m. (9 experiments), 



and from 4749 m. 5133 m. for similar tubes covered with 

 plaited string. 



In a similar tube the velocity measured at successive intervals 

 of 25 m. varied from 



4671 m. 5980 m., 

 being least at the beginning. 



The general average of the velocities is 



5200 m. 



The irregularity of the results appears to be due to the difficulty 

 of obtaining leaden tubes of uniform internal diameter. The 

 duration of the phenomenon may also be influenced by the time 

 necessary to destroy the tubes. To get perfectly regular results it 

 would be necessary to have tubes which would not burst. This 

 has only been accomplished when working with gaseous systems. 



(3) With the same product contained in a tin tube, the density 

 of charge being slightly higher, that is over 1'2 } the average 

 velocity varied 



from 5736 m. 6136 m. for tubes of 4 mm. external diameter, 

 and from 5845 m. 6672 in. for tubes of 5'5 mm. diameter. 



II. NlTROHYDROCELLULOSE: 



Velocity per second. 



(25 m.) from 2nd to 3rd interrupter 6389m. 



(25m.) 3rd to 4th 5932 



(25m.) i, 4th to 5th ,, 6435 



Mean velocity 6242 m. 



Experiments were also made in a tin tube, consisting of two 

 parts, one 4 mm., the other 5'5 mm. in diameter. The general 

 average velocity in the 4 mm: tube was 



4919 m. 



and in the 5'5 mm. tube 6100 m. 



Apparently the velocity was rather more rapid in the tin tubes 

 (5916 m.) than in the leaden ones (5200 m.) ; perhaps because the 

 former metal resists longer than the latter the explosive effort 

 which destroys the tube. 



III. GRANULATED GUN-COTTON. 



At high density of charge, 1'17, in a tube 2 mm. internal 

 diameter, the average velocity was 



4770 m. 



In a tube 3-15 mm; internal diameter, density of charge 1'27, 

 the mean velocity was 



5406 m. 



This greater velocity was due to the greater diameter of the tube 

 and density of charge. 



2N2 



