Hydrometer 'Philosophical Bubbles' by James Corte, Glasgow
Object No. H5266
These 'Philosophical Bubbles' were invented by Alexander Wilson of Glasgow University around 1750 to test the specific gravity of liquids. In 1805 Edinburgh glassworker Isabell Lovi improved the instrument. This set was made by James Corte in Glasgow, probably between 1750 and 1805. It is much easier to use than other hydrometers: just note the number engraved on the bubble that sits in your fluid (in this case, an alcoholic drink) without sinking or rising to the surface. The common hydrometer, exemplified by the Sykes type that was in official use for many years for proving the alcohol content of spirits, could have been invented by the ancient Greek mathematician Hypatia, and it was certainly known to her. This set of bubbles or beads, invented around 1750, is interesting as it embodies both well honed craft skills and a radically different approach to proving spirits. Like Hypatia's hydrometer, this set is based on the understanding that the buoyancy of solid objects in a fluid is directly related to the specific gravity of the fluid. Unlike Hypatia's hydrometer, it is simple to use and still works if part of the set is broken. To use these bubbles, select a few that are close to the expected density of the fluid under test. Place them in a sample of the fluid and observe which ones float and which ones sink. Read the number on the one that just floats, and check where it sits on the list inside the lid of the box that contains the bubbles. As density varies with temperature, a correction will need to be applied if the measurement is not performed at the temperature for which the bubbles are calibrated. A variation on the bubble approach was developed in the nineteenth century for testing the specific gravity of battery fluid, which is proportional to its state of charge. In that hydrometer, a small number of coloured bubbles sat within a glass tube, and the user simply observed which bubbles floated and which sank. Debbie Rudder, Curator, 2014
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Summary
Object Statement
Hydrometer, containing spirit hydrometers (17) in circular box, glass / wood / paper / textile, made by James Corte, Glasgow, Scotland, 1750-1805
Physical Description
Hydrometer, 'Philosophical Bubbles' or 'Gravity Beads', 17 spirit hydrometers in circular wooden box for gauging density of liquids, glass / wood / paper / textile, made by James Corte, Glasgow, Scotland, 1750-1805 Set of 17 spirit hydrometers in a circular box made of polished wood. Each one is a hollow glass sphere with a small stem that was detached from the glassblower's blowpipe. Opposite the stem on each bubble is etched a number that indicates its specific gravity. The stems of the bubbles fit into holes provided in the textile-covered base of their box. On the inside of the lid is glued a piece of paper bearing the maker's name and address and a list of spirits and the numbers of the beads that just float in them. A thin disc of cotton wool sits between the bubbles and the lid. In use, beads are placed in the spirit to be tested, and the number is read from the bead that just floats.
DIMENSIONS
Height
33 mm
Width
85 mm
Depth
85 mm
PRODUCTION
Notes
Dr Alexander Wilson, professor of astronomy at Glasgow University, invented this type of hydrometer around 1750. Mrs Lovi, a member of a family of glassblowers of Italian ancestry who had settled in Scotland, later improved the instrument. This set was made by James Corte, who had premises in the Saltmarket, Glasgow, but the dates of his production are unknown. Reference Brewster, David, The Edinburgh Encyclopaedia, J & E Parker, 1832, volume 10, p 783
HISTORY
Notes
Nothing is known about the provenance of this set, other than that it was donated by Robert Craig Dixson, company director, inherited wealth from his grandfather and father, tobacco merchants Hugh Dixson and Sir Hugh Dixson. Family members were well-known collectors and philanthropists; this Museum has a collection of tsuba acquired by Sir Hugh and his wife. Robert could have acquired the hydrometer from his uncle, Sir William Dixson, who studied engineering at Glasgow, worked in the family firm, endowed the Dixson Library in Sydney, and died in 1952.
SOURCE
Credit Line
Gift of Robert C Dixson, 1954
Acquisition Date
20 January 1954
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