1st May, 2013 12:00
Maritime and Scientific Models, Instruments & Art (Excellent)
228
[M] AN 18th-CENTURY BOXWOOD ALCOHOL PROOF SLIDE RULE BY T. GILL, LONDONv
AN 18th-CENTURY BOXWOOD ALCOHOL PROOF SLIDE RULE BY T. GILL, LONDON
calibrated over both sides, signed and stamped T. Gill / PROOF -- 8¾in. (22cm.) diameter (closed)
This slide rule is Thomas Gill's version of the proofing rule invented by John Dicas (London, w.1774-1797) for use with his hydrometer. Dicas was awarded a patent (no. 1259) for his hydrometer used with a sliding rule in 1780. Essentially it functions as a sliding chart that can be adjusted for the difference in density of the liquor according to its temperature.
AN 18th-CENTURY BOXWOOD ALCOHOL PROOF SLIDE RULE BY T. GILL, LONDON
calibrated over both sides, signed and stamped T. Gill / PROOF -- 8¾in. (22cm.) diameter (closed)
This slide rule is Thomas Gill's version of the proofing rule invented by John Dicas (London, w.1774-1797) for use with his hydrometer. Dicas was awarded a patent (no. 1259) for his hydrometer used with a sliding rule in 1780. Essentially it functions as a sliding chart that can be adjusted for the difference in density of the liquor according to its temperature.
Auction: Maritime and Scientific Models, Instruments & Art (Excellent), 1st May, 2013
