THE ELOCITY OF A RIFLE BALL.

Kumara Times, Issue 1092, 31 March 1880, Page 3

THE ELOCITY OF A RIFLE BALL.

— + A pretty illustration of the extent to which practical demonstration is sometimes carried in popular scientific lectures was given one evening lately in the Cooper Institute* New York, when Professor Spice measuiect, before a large audience, the velocity of a rifle ball fired across the stage. The distance was only 33ft. Lieutenant Merriarn co-operated, and his duty was to shoot away, with a Creednioot rifle, two loose wires, each of tvhich connected in an electric chcuib two Lglo-

bules of mercury. One wire was placed just in the front of the supported tAuzzle of the rifle, the other 33ft 'distant, Two levers were arranged,;, with bent-wire points, over a piece of smoked glass, to which a uniform motion, could he imparted, and the electric connections were such that on the first wire being'hroken the point of the corresponding lever descended on the glass ; but when the bullet broke the second wire it immediately rose again by the action of a spring. The result of this was that the point connected with this lever scraped a very short line on the smoked glass. The other point, being kept down during the swing of a second pendulum, scraped a longer space. After firing, the glass was withdrawn, and a magnified image of the lines thrown on a screen. The relative lengths of these lines were then ascertained) the longer being fonnd HOin, the shorter oin, making the duration of flight of the ball fi-llOth of l-22ud of a second. Hence its rate of motion was 33x22—equal to 726 ft in a second.