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Papers on the galvanic longitude of Valentia, 1862

Reference Code: GBR/0180/RGO 6/637

Scope and Contents

Correspondence and papers regarding the operation to discover the longitude of Valentia (Valencia), Ireland, by means of electric telegraph. The papers include correspondence on the project's requirements, preparations, arrangements and expenses; material produced during the earlier Ordnance Survey of the island, including tracings of the island and of Kingstown (Dún Laoghaire); papers on the loan of equipment; papers on the method of observation; E. Dunkin's daily journal kept during the operation, 9 June-23 July 1862; a record of signals from Greenwich and their sidereal times; a description of the altazimuth instrument used; observations and computations, including zenith points for the altazimuth and zenith distances, with clock times for vertical transits; computations of clock error; computed co-latitude of Polaris; computations and comparisons of sidereal times at Valentia and Greenwich, with a synopsis of the signal observations; final results giving longitude; and the velocity of the telegraphic signals. There is also an account of the whole operation by Airy. The correspondents include J. Washington, W.G. Romaine, H. James, A.R. Clarke, C.T. Bright, E. Dunkin and C. Wheatstone.


  • Creation: 1862


Conditions Governing Access

From the Management Group:

Unless restrictions apply, the collection is open for consultation by researchers using the Manuscripts Reading Room at Cambridge University Library. For further details on conditions governing access please contact Information about opening hours and obtaining a Cambridge University Library reader's ticket is available from the Library's website (


2 archive box(es) (2 boxes)

Language of Materials


Former / Other Reference


Finding aid date

2006-01-06 11:53:01+00:00

Includes index.

Repository Details

Part of the Cambridge University Library Repository

Cambridge University Library
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Cambridge CB3 9DR United Kingdom