In this galvanometer a silvered quartz filament 14.7 cm long is held under tension and placed between the poles of a strong electromagnet. An alternating current passing through the fibre will cause it to vibrate and its motion can be observed with a microscope passing through the poles of the magnet. In images a and b the lower brass tubes are a condenser lens and a microscope and the upper brass tubes with pointed knobs are focusing adjustments. The fibre is held in a demountable box shown in image c and it can be seen through the small hole at the centre. Frequency response up to 100 Hz.
Cost in 1909 £57.10. 0

Inscriptions / Translations:  THE CAMBRIDGE SCIENTIFIC INSTRUMENT CO. LTD.
CAMBRIDGE ENGLAND
On magnet: NO. 6810
On case for vibrator: No. 6821
B’ham Univ Physics E 288

Notes:  An instruction leaflet is on file.
Cover missing.
Magnet coils have 600 turns each and are designed to run at 200 V.
The condenser lens and microscope are by C. Zeiss.