514 



TRANSACTIONS OF THE AMERICAN INSTITUTE. 



KIND OF GUN. 



6 pdr. field 



r 1 



1.5th 

 1.4th 

 1.3d 



.34 14S9 

 28+ 1563 

 21- 1741 



1596 

 1720 

 1898 



1368 

 1465 

 1623 



xt » 

 "^ o 



il. 



" ^^ 



.is .-i o 

 i. 3 o 



£ ^ (i 



6820 

 6899 

 6842 



12 pdr. field 



1370 

 1486 

 1635 

 1834 



1508 

 1624 

 1773 

 1972 



1257 

 1.373 

 1471 

 1630 



7208 

 7008 

 7274 

 7329 



12 pdr. siege. 



1378 

 1674 

 1906 



1516 



1812 

 2044 



7023 

 7259 

 7461 



Long 12 pdr 



I ^2 



I ^3 

 14 

 15 

 16 



U7 



1444 

 1742 

 1951 

 2098 

 2239 

 2300 

 2324 



1582 

 1880 

 2089 

 2236 

 2377 

 2438 

 2462 



1287 

 1615 

 1688 

 1825 

 1937 

 2030 

 2107 



-157 

 -227 

 -263 

 -273 

 -302 

 -270 

 -217 



-295 

 -365 

 -401 

 -411 

 -440 

 -408 

 -355 



7567 

 7713 

 7673 

 7518 

 7539 

 7222 

 6833 



24 pdr. siege. 



18 



19 



20 



(21 



1.8th 

 1.6th 

 1.4th 

 1.3d 



60+ 

 33+ 

 25 



1240 

 1440 

 1723 

 1870 



1394 

 1594 



1877 

 2024 



1127 

 1270 

 1489 

 1653 



-113 

 -170 

 -234 

 -217 



-267 

 -324 

 -388 

 -371 



7665 

 7892 

 7959 

 7511 



32 pdr. seacoast. 



22 

 23 

 24 



(25 



1.8th 

 1.4th 

 1.4th 

 1.3d 



60+ 

 45 

 30- 

 22 



1271 

 14.30 

 1640 

 1780 



1421 

 1580 

 1790 

 1930 



1124 



1266 

 1482 

 1642 



-147 



-164 

 -158 

 -138 



-297 

 -314 

 -308 

 -288 



7994 

 7799 

 7302 

 6913 



Mean of pressures 7369 



The columns " approximfite values of n" and "No. of Tolumes expansion," 

 are introduced for convenient comparison. The second consists of the values 

 of X at the moment of the expulsion of the shot. These numbers are ap- 



proximate, like the values of n. In the calculation the exact values are in 

 all cases employed. The column of pressures contains the computed 

 initial pressures w^hich would be necessary to produce the velocities cor- 

 rected for windage. The results presented in the preceding table are 

 certainly surprising. While anything like a close agreement between 

 computation and observation was hardly to be expected, every reason for 

 anticipating a discrepancy would indicate that the computed velocities 

 should be in excess and not in deficiency, and the computed pressures in 

 deficiency and not in excess. The formula assumes that the gases a)e fully 

 developed, before the shot begins to move. In point of fact, we know that 



