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An Early 19th Century Chondrometer Steelyard Scale for Weighing Grain by J. Bleuler. This rare and important instrument, made of brass and steel, was used to measure the quality of grain by determining the heaviness of a Test Weight of grains and its packing density (Specific Gravity). The test weight is reported as the weight (in lb) of an imperial bushel of grains in units of lb/bu. Higher test weights indicate plump kernels that pack tightly into a specific volume. The scale arm is engraved with the maker’s name and with a number 8 to specify that the scales were made to convert the weight of a full bucket into 8 gallons. (The Imperial bushel contains 8 Imperial gallons). A wooden rod or ‘flat strike’ was used to smooth the excess grain away by drawing the rod or the strike across the top of the bucket. The inside lid contains a label with instructions and normal values of test weights for 9 marketable grains. John Bleuler, Optical and Mathematical Instrument Maker, worked in London from 1757 until his death in 1829, he was an apprentice to Henry Shuttleworth from 1771 until 1791 when he took over the business of a Mr Whitford at 27 Ludgate Street, London. He made a wide range of instruments that may be seen in many museums. This information helps to date the scales to 1791 – 1829. |
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