Accession No
5000
Brief Description
Lucas Pendulum, by Cambridge Scientific Instrument Company Ltd., English, 1907
Origin
England; Cambridge
Maker
Cambridge Scientific Instrument Company Ltd.
Class
electrical; medical
Earliest Date
1907
Latest Date
1907
Inscription Date
Material
metal (steel, brass, iron, other)
Dimensions
overall height 720mm, overall breadth 490mm; base length 360mm; base breadth 360mm
Special Collection
Provenance
Transferred from the Department of Physiology, University of Cambridge, 23/01/1997.
Inscription
‘The Cambridge Scientific Instrument CO. LTD. Cambridge England NO 5140’ [circumference on wheel]
Description Notes
Lucas Pendulum, by the Cambridge Scientific Instrument Co, English, 1907.
Black-painted cast iron triangular base supports black-painted standard. The standard supports a brass wheel on a brass axle. Wheel with four spokes and a degree scale divided 0 - [178˚], numbered by 10˚, subdivided to 1˚, with vernier reading to 0.1˚. Electrical key set on right hand side of the wheel; second key set at base of wheel; clamp on base for holding wheel in place, with knurled brass clamping screw. Axle carries a black-painted cast iron bearing which supports a short cast iron pendulum, pointing upwards; plastic weight set partway up pendulum. The pendulum is free to move between two pawls (one missing) on a short arc positioned in front of the top of the wheel.
Condition poor (very tarnished and rusty); incomplete (one pawl missing).
References
Events
Description
The Lucus Pendulum is a more sophisticated form of contact breaker and enables electrical circuits used in physiological experiments to be opened in succession at definite intervals of time. It may be used for investigating the refractory period of a nerve or muscle and determining the minimum strength of a current which will excite a nerve or muscle, when applied for different durations of time as well as many other experiments.
From Cambridge Scientific Instruments catalogue. “The instrument comprises a short pendulum mounted on ball bearings and carrying a light weight arm which engages with two pawls pivoted upon a vertical frame. The pendulum is first brought in to such a position that the arm rests against the left pawl. When this pawl is raised, the pendulum swings in an anticlockwise direction through nearly 3600, causing the arm to open two electrical contacts in succession before reaching the second pawl at the top of the instrument (and its swing). One contact is attached to the base of the instruement at approximately 1800. The other contact is attached to a rotatable vertical wheel 490mm in diameter, which can be clamped in any position. This wheel is graduated in angular degrees over 150 degrees of its circumference, and a vernier enables the position of the contact to be read to 0.1 degree. The time interval between successive openings of the two contacts may be varied from 0.00008 second to 0.16 second.”
20/01/1999
Created by: Hester Higton on 20/01/1999
FM:41602
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