Accession No

4112

Brief Description

rolling trolley electrocardiograph (ECG), by Cambridge Instrument Company Ltd., English, 1936 (main instrument, camera and galvanometer), 1931 (fibre case)

Origin

England; Cambridge and London

Maker

Cambridge Instrument Company Ltd.

Class

medical

Earliest Date

1931

Latest Date

1936

Inscription Date

Material

wood (mahogany, 2 others); metal (brass, copper; at least 3 others); cloth (cotton); plastic (ivorine, at least 4 others); rope (string); glass; hide (leather); ceramic

Dimensions

length 1760mm; breadth 530mm; height 1490mm

Special Collection

Cambridge Instrument Company Collection

Provenance

Donated by the Cambridge Instrument Company.

Inscription

‘Cambridge
Instrument Co. Ltd.,
England’ (Einthoven galvanometer)
‘Cambridge Instrument Co. Ltd., England.’ (main control panel)
‘Cambridge
Instrument Co. Ltd.
London & Cambridge.
C204558’ (ivorine plaque on falling plate camera)
‘Cambridge Instrument Co. Ltd.
England’ (vibrating bar)

Description Notes

Rolling trolley electrocardiograph (ECG), by the Cambridge Instrument Company; main instrument, camera and galvanometer 1936; fibre case 1931.

Large wooden trolley with rubber-coated wheels (rubber perished). At one end is a roller (perhaps for a towel). At the other end is the stand for the falling plate camera. This consists of a mahogany case with hinged back door and close fitting top cover. Back door has rectangular opening which is filled with a black cotton light trap. At the front of the casing is a horizontal slit behind which is mounted a cylindrical lens. The shutter is divided into 3 parts which can be raised or lowered by wooden knobs. A scale in front of the shutter divided 40 - 0 - 40 numbered by 10 subdivided to 1. Inside the casing a photographic plate is suspended on a system of brass wires. The plate is fitted with a light-proof roller-blind shutter. The speed of the plate movement is controlled by a pulley movement and piston which is set outside the main instrument. The piston moves in a black-painted metal cylinder, filled with oil.
Set half way down the trolley is a phonic wheel consisting of a wheel with five short radial spikes, set between a horizontal pair of electromagnets; strong magnifying lens for magnifying image of phonic wheel (?).
Einthoven galvanometer: 2 large leather-covered coils mounted around a U-shaped iron block, which acts as the core of the electromagnet, and is supported on three levelling feet. Set vertically between the poles of the magnet is the fibre case containing the fibre. The fibre can be viewed through a small glazed hole by means of a microscope set into one side of the electromagnet, the other side carrying a tube through which the fibre can be illuminated. Two pairs of brass terminals are connected to coils, and allows coils to be connected either in series or in parallel. Terminals on fibre case for connecting fibre to ECG electrodes.
On the front panel of the trolley is a control panel on the left. This has a glazed voltmeter set in brass; scale divided 0 - 1, numbered by 0.5; dial for selecting the electrodes; dial for setting voltage; dial unmarked apart from arrows; push-button marked ‘depress to insert 4000 ohms’; push-button marked ‘depress to connect cell’; further dial marked adjust rheostat. On the right of the panel is a set of switches in bakelite; three switches are marked on ivorine plaques ‘camera motor’, ‘field’, ‘lantern’ and ‘time marker’; fifth unmarked switch.
Vibrating bar set between springs attached to top of trolley and bottom shelf; black-painted cast iron base bar, supporting white metal vibrating bar . The bar carries a weight at one end. Near the other end it is attached to three brass strips, which make a connection with a brass screw on the base bar. Near the far end an electromagnet is set over the vibrating bar, and two leads run from this to a pair of brass terminals on the base bar, marked ‘time marker’; third terminal marked ‘battery’.
Lamp underneath trolley, also various electrical connections.

Condition fair; complete.

there is a dust cover with object (10/01/2022)

References

Events