OF ARTS AND SCIENCES : SEPTEMBER 11, 1866. 139 



Diameter of calibre, 15 inches. 



Weight of gun, 49,099 pounds. 



Weight of shell, 315 " 



Charge of powder, 50 " 



Initial velocity of shot, 1,118 feet. 



From which we obtain : — 



Height to which the shot will rise in vacuo, 19,530 feet. 



Force in pounds raised one foot high, 6,051,950. 



Force compared with the 32-pound shot under a velocity of 1,600 feet a 



second, this being taken as 1, 4.80. 

 Force in number of horses workins: one minute, 186.4. 

 Number of pounds (in shot) raised one foot high by each pound in the weight 



of the gun, 125. 



Next let us examine the 300-pounder coil gun, as constructed by Sir 

 William Armstrong. This is described as follows: — 



Diameter of calibre, 10^ inches. 



Weight of gun, 26,880 pounds. 



Weight of shot, 300 " 



Weight of charge, 60 " 



Initial velocity of the shot, 1,500 feet. 



From which we obtain the following: — 



Height to which the shot will rise if fired in vacuo directly upwards, 35,156 feet. 

 Force in pounds raised one foot high, 10,546,800. 

 Force compared with a 32-pound shot, being taken as 1, 8.24. 

 Force in number of horses working one minute, 319. 



Number of pounds raised one foot high (in shot) for each pound of metal in 

 the gun, 392. 



The last gun that I propose to examine is the Armstrong coil gun 

 throwing a 600-pound shot. Described as follows : — 



Diameter of calibre, 13|- inches. 



Weight of gun, 49,280 pounds. 



Weight of shot, 600 " 



Charge of powder, 100 " 



Initial velocity, 1,400 feet. 



These elements give the following results : — 



Height to which the shot will rise, if fired in vacuo, 30,625 feet. 

 Force in pounds raised one foot, 18,375,000. 

 Force, a 32-pound shot taken as 1, 14.35. 

 Force in number of horses one minute, 556.8. 



Number of pounds raised one foot high (in shot) by each pound of metal in 

 the gun, 372.8. 



The foregoing facts are comprised in the following table : 



