Accession No

6088

Brief Description

beam balance used in physiological experiments to measure the effect of temperature on the water-proofing mechanism of cockroaches, by James W. L. Beament, English, 1950s

Origin

England; Cambridge

Maker

Beament, James W. L.

Class

physiology; laboratory apparatus; balances

Earliest Date

1940

Latest Date

1958

Inscription Date

Material

plastic (polystyrene); metal (steel, nichrome wire, phosphor-bronze wire, bronze, copper-constantan, Elektron metal, other); organic (rubber, insect)

Dimensions

length 520mm; width 200mm; height 300mm

Special Collection

Provenance

Donated on or before 28/10/2005. The balance was made by the donor's late husband, Professor Sir James W. L. Beament FRS, who worked on the waterproofing mechanism of insects.

Inscription

Description Notes

Beam balance used in physiological experiments to measure the effect of temperature on the water-proofing mechanism of cockroaches; by J. W. L. Beament; 1950s

Polystyrene box on four metal legs, with lid designed to provide an airtight seal. (nb. box is solid polystyrene and not the expanded type). Opening for plastic tubes at ends of the box, each with sealing devices, to allow dry air to be flushed through the box. Small capillary open to the atmosphere to allow for thermal expansion during the experiment.

Box contains fan-heater element to heat the inside of the box and the insect specimen. The leads for the heater are brought in through air-tight seals in the base of the box. Box contains balance beam made of Elektron metal (a magnesium/aluminium alloy), which is perforated to reduce its weight.

Insect specimen is supported on one end of the beam on a grid of phosphor-bronze wires, providing good air circulation around the specimen. Specimen holder is strengthened by bronze rods running to the centre of the beam, which also carry the thermocouple current to the suspension.

The other end of the beam carries an adjustable counterweight and graduated slide for ‘rider’ weights. Thermocouples are 44 s.w.g. (standard wire gauge) copper-constantan and all parts of the thermocouple circuit are coated with distrene cement for insulation purposes. Suspension system is set up to allow the beam to rest on v-shaped supports whilst the specimen is being mounted, thus protecting the delicate suspension.

The side of the beam carrying the counterweight also holds a torsion balance for measuring small changes in weight.

Second part of object is smaller acrylic box with metal rod extending from it. From the scientific papers the function of this part of the instrument is unclear.

Condition good; some yellowing to polystyrene box.

References

Events