CAPTAIN NOBLE AND MR. E. A. ABEL ON EIRED GUNPOWDER. 
Ill 
In this Table column- 1 gives the distances of the various plugs from the seat of the 
shot in feet, see fig. 3, Plate 18 (the distance from the seat of the shot to the bottom 
of the bore being 2 feet=-610 metre). Column 2 gives the same distances in metres. 
Column 3 gives the observed time of passing each plug. Column 4 gives the corrected 
time from the commencement of motion, the time from the commencement of motion 
to the first plug being interpolated. Column 5 gives the differences of time — that is, 
the time taken by the projectile to traverse the distance between the plugs. Column 6 
gives the mean velocity of the projectile over the space between the plugs, in feet; and 
column 7 gives the same velocities in metres. 
Table IX. — Giving data obtained with chronoscope for calculating velocity and pressure 
in the bore of a 10-inch 18-ton gun. Charge 70 lb. (31-75 kilos.) pebble powder. 
Weight of projectile 300 lb. (136-05 kilos.). Muzzle-velocity 1527 ft. (465-4 metres). 
1 . 
2 . 
3. 
4. 
5. 
6. 
7i 
Distance from seat 
of shot. 
Time observed 
at plugs. 
Total time from 
seat of shot. 
Time taken by 
shot to traverse 
distance 
between plugs. . 
Mean velocity over 
spaces between plugs. 
feet. 
0-00 
0-06 
0-26 
0- 46 
0-66 
0*86 
1- 06 
1- 46 
1-86 
2- 26 
2-66 
3- 46 
4- 26 
5- 06 
6- 66 
8-26 
metres. 
0-000 
0-018 
0-079 
0-140 
0-201 
0-262 
0-323 
0-445 
0- 567 
0-689 
0-811 
1- 055 
1-298 
1- 542 
2- 030 
2-518 
seconds. 
•000000 
•001096 
•001611 
•001967 
•002272 
•002548 
•003036 
•003469 
•003869 
•004244 
•004947 
•005605 
•006234 
•007426 
•008554 
seconds. 
•000000 
•002683 
•003779 
•004294 
•004650 
•004955 
•005231 
•005719 
•006152 
•006552 
•006927 
•007630 
•008288 
•008917 
•010109 
•011237 
seconds. 
•002683 
•001096 
•000515 
•000356 
•000305 
•000276 
•000488 
•000433 
•000400 
•000375 
•000703 
•000658 
•000629 
•001192 
■001128 
feet per 
second. 
22 
183 
388 
562 
656 
725 
820 
924 
1000 
1065 
1138 
1215 
1273 
1342 
1418 
metres per 
second. 
6-7 
55-8 
118-3 
171-3 
199*9 
221-0 
249-9 
281-6 
304-8 
324-6 
346-9 
370-3 
388-0 
409*0 
432-2 
From these data are deduced, by correction and interpolation, the times given in 
Table X. From the differences of the times are calculated the velocities, and from the 
velocities the pressures necessary to produce them are obtained. 
