26 Experiments tip on Gnnpowder. 



who wish to see more on the subject to Mr. Robins's 

 New Principles of Gunnery ; to Professor Euler's Ob- 

 servations upon Mr. Robins's Boole ; and lastly, to 

 Dr. Hutton's Paper on the initial Velocities of Cannon 

 Balls, published in the Transactions of the Royal So- 

 ciety, for the year 1778. 



If a denote the length from the axis of the pendulum 

 to the ribbon which measures the chord of the arc of its 

 vibration ; 



g the distance of the center of gravity below the axis 

 of the pendulum ; 



y the distance of the center of oscillation ; and 



h the distance of the point struck by the bullet from 

 that axis ; 



c the chord of the ascending arc of the pendulum ; 



P the weight of the pendulum ; 



h the weight of the bullet, and 



V the original velocity of the bullet ; 



a bk f sl-ih _ 



is a theorem for finding the velocity upon Mr. Robins's 

 principles. 



« bh 2/ V 2 



is the theorem proposed by Professor Euler, who has 

 corrected a small error in Mr. Robins's method ; and 



z. = 5.672 cgff^ ^, 



* Put the rational part - X ^? -|- - ^ "^ - = n and express / in thou- 

 '''• /' // 2/ 



sandth parts of a Rhynland foot ; tlien the velocity with which the ball 

 strikes the pendulum wiU be = - ^ L Rhynland feet in a second. 



