CAPTAIN NOBLE AND MR. F. A. ABEL ON PIRED GUNPOWDER. 
115 
Table XI. gives the results of the calculations necessary for obtaining the values of 
s, v, and T from equations (10), (11), and (12). 
To avoid repetition, we have introduced in this Table the following abbreviations : — 
M=te+f 3t+ytf, ) 
N ~K — ryt 2 , 
[ (13) 
P = M(1 -f log e £) — N log e t, | 
F=/3+(/3-4y0.(l+log.i);J 
and the values furnished in Table XI. can be compared with those given in Table X. 
But the comparison, both as to velocity and pressure, can be more readily seen by a 
graphical representation ; and we have accordingly laid down in Plate 20, in full black 
lines, the curves of velocity and pressure taken from Table X. 
The results of Table X. have already been graphically represented in Plate 19 ; but 
in Plate 20, t instead of s is taken as the independent variable, with the view of 
enabling the accordance of the methods to be more easily compared. The curves in 
dotted lines indicate the velocity and pressure shown in Table XI., and deduced from 
formulae (10), (11), and (12). 
It will be observed that the two curves of velocity approximate exceedingly closely. 
The difference between the pressure-curves also is not greater than might be expected ; 
and the difference, such as it it, is due to our not having succeeded in obtaining an 
equation which represents the corresponding observed values of s and t so closely as do 
the values given in Table X. 
The pressures given by the crusher-gauges (which can be compared with those given 
in either of the Tables X. or XI.) at the points A, B, C, 1, 4, are respectively 17’2, 
15'6, 15-6, 12‘8, and 11T tons per square inch, or in atmospheres, 2169, 2376, 2376, 
1949, and 1690. 
We now pass to the consideration of the results furnished by E. L. G. powder. 
Taking, as in the case of pebble powder, the particular set of experiments where shot 
of 300 lb. (136'05 kilos.) were used, the data furnished by the chronoscope are given 
in Table XII. (p. 117). 
