10,350 CHF
Dent, Chronometer Maker to the Queen, London, No. 2836, circa 1858.Very fine 56 hour marine chronometer with power reserve indication and Dent's prismatic continuous auxiliary compensation balance, second form. Three body mahogany box with brass corners, fixings and sunk brass handles, glazed upper section with hinged lid. Brass bowl and gimballed suspension. Silvered with Roman numerals, subsidiary seconds and Up-and-Down scale. Blued steel "pear" hands. Notes This chronometer incorporates the very rare Dent's registered prismatic compensation balance type "B" as improved by Frederick Rippon in 1852.This balance corrects the secondary error without any secondary mechanical contrivance, and does not increase the expense, whilst its prismatic figure adds great strength to the balance rim, rendering the chronometer far less liable to injury from transit, and its performance more uniform.Dent's superior marine chronometers, fitted with the prismatic balance were retailed at the price of 40 Guineas each.On November 10, 1851, Dent wrote from 61 Strand to Airy to ask his opinion on a plan which he thinks might have the effect of correcting the want of agreement between the inertia of the balance and the varying elastic force of the balance spring in a chronometer, in order to get rid of the secondary compensation which at all times is objectionable. The plan suggested for experiment was to alter the shape of the steel in the balance spring from that of cylindrical form Read more…
Auctioneer:
Antiquorum
Date:
1999-10-23
