Accession No

1110

Brief Description

mercury-in-glass hydrometers, by William Twaddell, 1828

Origin

Scotland; Glasgow; 84 Saltmarket

Maker

Twaddell, William

Class

physics; metrology

Earliest Date

1828

Latest Date

1832

Inscription Date

Material

glass; wood; metal (brass, mercury, steel); paper; cloth (velvet, silk, padding)

Dimensions

length varying between 126mm and 133mm; maximum diameter varying between 22mm and 24mm box length 150mm; breadth 149mm; thickness 48mm

Special Collection

Cavendish collection

Provenance

Transferred from the Cavendish Laboratory, University of Cambridge, from 10/1951. From the Wollaston collection. It is recorded in the Cavendish Laboratory's 1894 alphabetical catalogue of apparatus on p.87.

Inscription

‘WILLIAM TWADDELL,
SPIRIT PROOF MAKER,
NO. 84, SALTMARKET,
GLASGOW.’ (paper label inside lid of box)
‘Arometer made by Willm Twaddell, Glasgow.’ (hydrometer scales, only clearly visible on one with widest spindle)

Description Notes

Five (of six) pear-shaped bulb glass hydrometers, mercury weighted, the scale written in ink on paper within the spindle.
Spindle 1: divided 0 - 24, numbered by 2, subdivided to 0.5.
Spindle 2: divided 24 - 48, numbered by 2, subdivided to 0.5.
Spindle 3: divided 48 - 74, numbered by 2, subdivided to 0.5.
Spindle 4: divided 74 - 102, numbered by 2, subdivided to 0.5.
Spindle 5: missing
Spindle 6: divided 138 - 170, numbered by 2, subdivided to 0.5.
Fitted wooden box with brass hinges and hook fastener; blue silk lining in lid over padding; black velvet lining in box; letterpress label in lid.

Condition good (silk in case very worn); incomplete (one hydrometer missing)

References

Events