The most simple of these is an indiarubber ball pressed upwards into the narrow of the bottle neck by the force of the gas contained in the water; and in another system a glass ball is similarly pressed against an india-rubber collar inserted in the neck of the bottle.
To vibrate by means of two c, c', Inner portions of wings rods which extend between attached to central shaft of the crank and the roots of f, India-rubber in a state of model by elastic bands at e.
The induction coil is carried upon the end of one portion of the test bar, and when this portion is suddenly drawn back the coil slips off and is pulled out of the field by an india-rubber spring.
Thefollowing are the measurements of the model in question: - length of wing from tip to tip, 32 in.; weight of wing, tail, frame, india-rubber, &c., 73 grammes (about 22 ounces).
The coins are then gripped by a pair of india-rubber driving wheels, which force them past the rim of a thin disk with notches in its edge to fit the coins.