Late Eighteenth Century Hydrostatic Bubbles by Charles Aiano London

For sale a rare set of late Eighteenth Century hydrostatic bubbles by Charles Aiano, London.

The early forefather of the more widely known Sikes hydrometer which was invented in 1802, these interesting instruments are also known as philosophical bubbles, specific gravity beads, aerometrical beads or hydrostatic beads. Described on the paper label affixed to the underside of the lid as ‘Hydrostatic Balls for Spirits’ they were invented in 1757 by Dr Alexander Wilson (1714-1786) a Scot who rose to become the first Professor of Practical Astronomy at Glasgow University and was a founder member of the Royal Society of Edinburgh.

A contemporary biographical account of Wilson’s life relates that in 1757:

“He invented the hydrostatical glass-bubbles, for determining the strength of spirituous liquors of all kinds, which long experience, especially among the distillers and merchant in the West Indies, has now shown to be more accurate and more commodious than the instruments formerly used. From the minutes of a Philosophical and Literary Society, composed of the Professors and some of their friends, whose meetings were held weekly in the college, it appears that these hydrostatical bubbles made the subject of a discourse delivered by Wilson in 1757. At this time he also showed how a single glass bubble may serve for estimating very small differences of specific gravity of fluids of the same kind, such as water taken from different springs, or the like. This he did by varying the temperature of such fluids, till the same bubble, when immersed, became stationary at every trial, and then expressing the differences of their specific gravity, by degrees of the thermometer, the value of which can be computed and stated in the usual manner”.

This particular set of hydrostatic bubbles is comprised of a turned mahogany case with a diameter of three and a half inches. The removal of the lid reveals a set of 13 glass bubbles and 19 holes (six bubbles are missing or were never present) with a paper label denoting the various proof levels for the types of spirits being measured. The glass bubbles themselves consist of a bulb end with differing sizes of glass stalk and a corresponding number engraved to the top. The paper label states,

“Hydrostatic Ball for Spirits by Charles Aiano” and lists various spirits including wines, whiskey, rum, brandy & gin with notes on which bubbles are required for the measurement and the thermometer temperature required for the liquids to be measured.

The maker, Charles Aiano is a name more often associated with barometers and he is one of the most recognisable names amongst those early Italian makers whose families emigrated to the UK at the end of the Eighteenth Century. Although Aiano was born in Canterbury in 1784, his family hailed from the Northern regions of Italy around Lake Como. His early apprenticeship into the instrument making industry is not well understood but it is certain that he trained and then traded in London for the majority of his career. Numerous barometers bear his London signature and he made various unusual examples including multi-tube variations and angle barometers amongst the standard wheel and stick designs of the period.

For reasons unknown, Charles is registered back in Canterbury by 1826 and records show that he continued to trade and live there until his death in 1859.   

A rare set, and unusual as they are normally accompanied with Scottish makers labels rather than London ones. Please note, there is a small area of wood missing from the rim of the bottom of the case, a common fault with these which has been considered within the price.

Circa 1795