MEASURING THE SPEED OF A RIFLE BULLET.

Globe, Volume XXII, Issue 1903, 31 March 1880, Page 3

MEASURING THE SPEED OF A RIFLE BULLET.

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 Piofessor Spice measured, before a largo audience, the velocity of a rifle ball fired aoross the itage. The distance was only 33ft. Lieutenant Merriam co-operated, and hiß duty was to shoot away, with a Creedmoor rifle, two loose wires, one of which connected in an electric circuit, two globules of mercury. One wire was placed just in front of the supported muzzle of the rifle, the other 33ft. distant. Two levera were arranged, with bent-wire points, over a piece of smoked glass to which a uniform motion could be imparted, and the electric connections were such that on the first wire being broken the point of the corresponding lever desconded 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 oonnected with this lover 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 spaco. After firing, the glass waß withdrawn, and a magnified image of the lines thrown on a screen. The relative lengths of these lines were then ascertained, the longer being found 110 in„ the shorter sin., making the duration of the flight of the ball 5-110th of the 1 22nd of aaocond. Hence its rate of motion was 33 x 22 —equal to 726£t. in a second.