158 W. E. Woodbridge on the Pressure of Fired Gunpowder. 
the instrument was made at the temperature at which the gun 
was fired. In the brass gun several holes were made for receiv-. 
ing the instrument at different distances (specified in the table) 
from the bottom of the bore. When not in use, these holes 
were closed by plugs fitted to eac 
In the experiment with the taasices barrel, a part of the 
breech-end, in the rear of the charge, was made to serve as a 
substitute for the cavity of the screw plug, in receiving the pie, 
zometer. ; 
The experiments.are to be regarded altogether as peering ary 
trials, but they are not, I hope, without interest and value. The 
following table presents the most interesting of the results, 
| Btperiments on the pressure id Jired Gunpowder, 
Bs 
e Powillt. Shot. Dist’nce Hy 
piezomet’r J 
GUN. , g i ee gi : btm ae Remarks. 
_ |Weig’t. | Height.| bee. }Diam. = 2 
Ibs. in. Ibs. in. in. ba. 
{| 125 | 35 | 640 (858 | (8:25) a3 Piezomet’r attach’d to 
“ ev 632 | « “ the bottom of the bore.) 
“ *, 2 “ . | 
ae j ‘ : a che 2 1% yen oo Rie ok 
6 pdre } “ 3°42 63 “ “ 
“15 | 40 6 32 sey bes 53 
“ “ 6°33 “ “ 0 
“ “ 6°29 “ “ 47° 
LA 4°55 | 631 * bk 59° 
ie el es Gg d ES ee “" 8° er in coe ge} 
« | 435 | 635 | « # 168° 
“ | 455 | 636 (3575) - 4 [53° 18510) /Mean of . solide 
« | « |684} « | 7g [50° | 9575\Mean unds. 
«| « |639 | « | are laa? | 7740Mean of 84 
bs 8; 6°38 wi 158 |52° } 957 Kis es 
. = 6-29 40 28'S = 50° 
Brass 4 “ “ 633 “ 318 “ 
6 pdr. “ « 6°36 “ 39°8 “ 
77 « 6°34 “ 478 “ 
“ 4:48 6 l l “ 1 “ 
“ 4°65 0 “ “ 
20/605} 0 |.. lige 
88 0 “ “ 14820 
20 | 565 | 636 |3:575)  « 20640 Mean of 2 rounds. 
4 0 ji 885 64. “ “ 20| 
15 | 438 1216 1366; 15 | « 20480 Cylinders =. to 2 bi 
“ “ee oo} “ “ 2) 
6 pdr. }} «| @ |ioag | « «  |g9° sor 
grains, in. 
70 | o7 | 666 0675 60° 
a 
Tn the first two experiments recorded in the —— 
the orifice of the piezometer was 3} inch es from the 
