For use on pump plate not less than 15 cm. dia Electric Bell operating on 4-6 volts AC/DC, suspended on rubber cord in bell jar. Fine coiled wire connections to terminals mounted in rubber bung sealing the jar.

Varnished wood, with glass front and membrane suspended on cord for loading with sand to show positions of nodes and antinodes. Overall length 760 mm.

Consists of a chrome plated brass resonance tube 100 cm long, brass reservoir 250 ml and a metre scale mounted on a metallic stand. With rubber tubing.

The versatile apparatus may be used as demonstration model with an overhead projector or as an economical method of allowing pupils to carry out their own investigations. Four legs are provided enabling the tank to also be used as a free standing bench model. Facilities are provided for mounting a ripple tank illuminant. A gantry is supplied for supporting a motor beam, the height of which is adjustable allowing it to be positioned for maximum effect. Ripples are produced by small 1.5V to 4.5V D.C. motor mounted on the wooden beam of 240 mm length. A cam is fitted to the motor spindle to give an oscillatory motion and a row of nine holes in the beam are for mounting the spherical dippers for production of circular ripples.

Best quality nickel-plated, plain shanks, with frequency marked, C (256), D (288), E (320), F (341), G (384), A (426), B (480), C (512). Complete set of EIGHT tuning forks, supplied in case.

For demonstrating the movement of progressive transverse waves. Comprises 22 small balls on wire rods, with eccentric motion attachment, with driving handle and fitted on polished wooden base.

Stand overall height 43 cm. for use in vertical or horizontal position, fitted with handwheel and wire helix belt drive to pully. Suitable for use with Savart wheel and disc and adopter to accommodate colour discs.

For demonstrating the production of beat frequencies. Comprises two nickel plated forks A (426.6) mounted on individual boxes. One fork is provided with adjustable mass by means of which frequency may be shifted from the nominal 426.6. When both forks are sounded a clearly audible 'beat' is produced, its rate depending upon the difference in frequency between the forks.

For demonstrating longitudinal and transverse motion, Consisting a number of eccentric disc supporting a series of metal rods on revolving the handle, transverse waves are obtained. Longitudinal waves are obtained with bent rods running in metal guide.

Steel wire close-wound helix 19mm, diameter, closed length 3 meters extending to approx. 9 meters, with looped ends.

For demonstrating wave motion. Helical coil of flat section tempered steel wire. Coil diameter 7.5 cm length closed 10 cm. fully extended 3 meters.

A. As above, but coil diameter 5 cm, length closed 7.5 cm.

Comprising a wooden resonance box of 114 cm length, 12.5 cm width and 10 cm height, with two rules 1 meter long sub-divided into millimeters. One each brass and steel wire of different diameter attached to fixed bridge and tensioned by fine adjustment pegs, two moveable bridges, pulley and fixed screw to enable a third wire to be fixed for tensioning by masses. One each additional wire of steel and brass, each 1.5 m lenght and of 22 SWG.