The Antiques Centre York Antique Tools

VINTAGE PHILIP HARRIS SOUND FREQUENCY APPARATUS Ref: 100-gd1029
A Rare Find
Philip Harris Scientific Instrument for measuring the sound frequency of a tuning fork
This vintage scientific instrument by Philip Harris Birmingham is in mahogany. I guess it dates from any time before 1950. These were used in physics lessons to calculate the speed of vibration of a tuning fork. The glass slide was smoked black in a candle flame and held at the top of the slide. A cat’s whisker (100% genuine from my cat's bed) is attached to the tuning fork with either plasticine or sealing wax. The tuning fork is “twanged” and the smoked glass dropped in its slide. As the cat’s whisker brushes the soot on the glass it leaves a wavy trace due to the vibrating fork. Since due to gravity the glass is falling at 9.80665 m/s² , the distance between each wave peak on the sooty trace can be calculated in vibrations per second, in the case of this tuning fork 320 hz (cycles per second).
Simple really!
At the back is a wooden screw adjuster to bring the glass exactly the right distance from the whisker.

Postage price on request

Price: £80.00

Quantity: