"Instrument For Demonstration Of Metallic Expansion - England 19th Century"
MAGNIFICENT INSTRUMENT FOR DEMONSTRATION OF METALLIC EXPANSION, SIGNED "W & S.JONES-LONDON". A METAL BAR IS PLACED ON THE FLAMES DELIVERED BY THE SMALL URNS AND ITS EXPANSION WILL PUSH A METALLIC NEEDLE WHICH INDICATES THE LENGTH OF THE EXPANSION BASED ON THE DIFFERENT METAL BARS (IRON, COPPER-ALUMINIUM ETC.) INSTRUMENT OF HIGH CONSTRUCTION QUALITY TYPICAL OF 'ERA. 
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