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A brass 'Roberval letter scale, mounted on a simple plain…
Lot No.
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Description:
A brass 'Roberval letter scale, mounted on a simple plain timber base, with a set of three weights ½oz, 1oz, & 2oz. English manufacture although maker's name not indicated. Provenance: The 'Britannia stamp Bureau' sale 253 October 2000. 16.5 x 100 base 15 x 6.5 x 5.5 cm high. Other Notes: as a result of the uniform Postal Act of 1840, when the present postal system began, aagreat number of scales were produced on which letters and parcels could be assessed for the postage due. Many of the machines during the nineteenth century carried details of the current postage rates. The most popular designs were based on the 'Roberval' principle. (the pans of a Roberval balance move in such a way that the radii of the arcs of motion of the weights are independent of their position on the pan. Wherever the weight is placed on the pan, it moves the same vertical distance. That is the 'Roberval principle' common to all of these kinds of balance.)
Estimate:
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Price:
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Category:
Unclassified