John Roger Arnold, London

• 2½ inch silvered dial, subsidiary seconds, gold hands, Roman numerals • Arnold detent escapement with bi-metallic Z balance, blued steel helical hairspring • gimballed brass bowl in a three tier rosewood box with ebonized banding and brass handles • dial signed Arnold, London, No. 509, movement signed on the backplate J.R. Arnold, Invt. et Fecit, No 509 • accompanied by numbered key

The dial is original, with a stain below London and surface scratches, running but imagine it will need cleaning as it has not undergone service for a considerable length of time, balance, detent spring all appear to be original, handles are oxidized. Key top original and numbered, the shank has undergone replacement in the 1960's. Accompanied by a dated letter from the restorer and a receipt for the work done. An endangered materials expert has tested the box and it is rosewood and not mahogany, We believe the box to be original. front right corner of ebonized banding now missing, box with surface wear and minor areas of splitting to wood. The glass to second tier with crack to the back right corner and some losses to banding at the back. Further accompanied by a box key.
"In response to your inquiry, we are pleased to provide you with a general report of the condition of the property described above. All dimensions in catalogue descriptions are approximate. Condition reports may not specify mechanical replacements or imperfections to the movement, case, dial, pendulum, separate base(s) or dome. Watches in water-resistant cases have been opened to examine movements but no warranties are made that the watches are currently water-resistant. Please note that we do not guarantee the authenticity of any individual component parts, such as wheels, hands, crowns, crystals, screws, bracelets and leather bands, since subsequent repairs and restoration work may have resulted in the replacement of original parts. Since we are not professional conservators or restorers, we urge you to consult with a restorer or conservator of your choice who will be better able to provide a detailed, professional report. Prospective buyers should inspect each lot to satisfy themselves as to condition and must understand that any statement made by Sotheby's is merely a subjective, qualified opinion. Prospective buyers should also refer to any Important Notices regarding this sale, which are printed in the Sale Catalogue. In particular, please note it is the purchaser's responsibility to comply with any applicable import and export matters, particularly in relation to lots incorporating materials from endangered species.NOTWITHSTANDING THIS REPORT OR ANY DISCUSSIONS CONCERNING A LOT, ALL LOTS ARE OFFERED AND SOLD AS IS" IN ACCORDANCE WITH THE CONDITIONS OF BUSINESS PRINTED IN THE SALE CATALOGUE."

**Please be advised that bands made of materials derived from endangered or otherwise protected species (i.e. alligator and crocodile) are not sold with the watches and are for display purposes only. We reserve the right to remove these bands prior to shipping.

Important Notice regarding importation into the United States of Rolex watches
Sotheby's cannot arrange for the delivery of Rolex watches to the United States because U.S. laws restricts the import of Rolex watches. The buyer or a designated agent may collect the property in the country of sale."

It would appear that No. 509 is unrecorded, however, No. 510, which also featured a Z balance is recorded in Vaudrey Mercer, Arnold & Son, p. 249 and 289 and Hans Staeger, 100 years of Precision Timekeepers  from John Arnold to Arnold & Frodsham, 1763-1862, pp. 339 and 340.

The Z balance was first used in 1791 on Arnold pocket chronometer no. 405/704. For a drawing of the Z balance, see Mercer, the Introduction, p. X. as well as Mercer p. 60. In the second text, it is noted that the balance was used as late as 1818 by John Roger Arnold.

John Roger Arnold, son of John Arnold the great chronometer maker and inventor, was born in 1769 and apprenticed to his father in 1783. He became Free of the Clockmakers' Company in 1796 and in the following year he joined his father in the firm of Arnold & Son. Following the death of John Arnold in 1799, John Roger continued the business on his own becoming Master of the Clockmakers' Company in 1817. Between 1830 and 1840 he went into partnership with Edward John Dent and after his death in 1843 the business was bought by Charles Frodsham.