SIR GEORGE AIRY'S TRANSIT OF VENUS 1874 EXPEDITION - A VICTORIAN BRASS-BOUND ROSEWOOD TWO-DAY OBSERVATORY CHRONOMETER

In a two-tier brass-bound rosewood box (missing hinged upper lid), with glazed observation panel, the front with circular maker's ivory roundel, above a shaped brass escutcheon and further ivory roundel engraved with an arrow and 'TWO DAYS', a brass carrying handle to the left side (the right side missing), the inner case with screwed quarter-mouldings and brass gimbals, the bowl numbered inside the base, with a bevelled glazed bezel, above the signed silvered dial detailed With Airy's Compensation and with Up/Down power-reserve indicator below the XII and seconds subsidiary, with government arrow in the centre above the VI, fine blued steel hands, the stone-spotted movement signed Charles Frodsham, London and with government arrow, the free-sprung balance with diamond end-stone and blued helical spring, above Airy's subsidiary compensation bar with a spring and small brass weight to the inner rim of the bi-metallic compensated balance, chain fusée movement with maintaining power and Earnshaw detent escapement

17cm square

CONDITION REPORT

With tipsy winding key.  The chronometer runs when wound.  As noted in the cataloguing it is missing the lid. The right hand carrying handle is lost but should be replaceable.  The screw attaching the brass lid stop is lost.  There are two breaks to the wooden surface in the glazed lid just under the cut outs for the upper hinge lids where I suspect that lid was forced at some time.  The case has a pleasing colour with some marks and knocks as would be expected with its age.  

This Observatory chronometer was used as the 'mean solar half-seconds chronometer' on Kerguelen Island for the Transit of Venus Observations on 8 December 1874.  This expedition was led by Rev. S. J. Perry, FRS.  It was one of five expeditions to create observatories in different locations, including to Hawaii, Egypt, Rodriguez Island and New Zealand.  These were formed by the Astronomer Royal Sir George Biddell Airy and planning began many years prior.  

Captain George Tupman, the chief organiser of the expeditions, lists the chronometers required, including Frodsham 3178, for the expeditions in his manuscript notebook dated 31 May 1874, which is at the Royal Greenwich Observatory (RGO 59/58).

The Transit of Venus, seen passing between the sun and the earth, is a rare astronomical event, occuring in pairs, separated by 6 years every 100 years.  A full account by Airy was published in 1881.

LITERATURE

Royal Observatory Archives, Greenwich, Transit of Venus, Tupman notebook (RGO 59/58)

https://cudl.lib.cam.ac.uk/view/MS-RGO-00059-00058/3

Account of observations of the Transit of Venus 1874, December 8, made under the authority of the British Government: and of the reduction of the observations, Edited by Sir George Biddell Airy, K.C.B., Astronomer Royal, London 1881.

IMPORTANT NOTICE

This lot contains ivory and has been registered in accordance with the Ivory Act (section 10).  Reference No. BFREL6MN.

Prospective buyers should be aware that some countries have limitations on importing items made from endangered species, including materials such as coral, ivory, and tortoiseshell.  Therefore, it is advisable for potential buyers to familiarize themselves with relevant customs regulations before placing bids, particularly if they intend to import this lot into another country.