Gravity Beads
Owner: J.S. Donovan

Gravity Beads 

Specific Gravity Beads
Complete Set


Maker : James Corte, Crawford's Land, foot of Saltmarket, Glasgow
One of the earliest known examples of a hydrometer for testing the proof of spirits. Known as Philosophical Bubbles or Specific Gravity Beads

It is been established that the above beads were made by James Corte, Crawford's Land, foot of Saltmarket, Glasgow in the 18th Century. This instrument served as an individual hydrometers for use in testing various alcoholic spirits. They were invented by Alexander Wilson in the mid 1750s. The quality of these small glass bulbs or bubbles could only been attained by highly skilled glass blowers of that era. Inside this case is the original paper and the list of spirits and each number and the makers name address. Also, each of the twelve beads are numbered.







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