The Isles of Scilly and the Channel Islands: "bench-mark" hydrographic and geodetic surveys 1689-1980

Abstract

The English Channel has been both a major maritime artery and a navigator's nightmare for many centuries. Two archipelagoes, the Isles of Scilly to the north and the Channel Islands to the south, have been and remain major hazards. The two archipelagos have long cartographic histories which have yet to be fully documented. The present study is, with two limited exceptions, confined to British official hydrographic surveys and more specifically to those that may be regarded as 'bench-mark' surveys , i. e. surveys that made significant advances in 44& charting the two archipelagoes. The study is further restricted to describing and assessing the progressive attempts to fix accurately the latitudes and longitudes of the two archipelagos and their relationships to west Cornwall on the one hand and the Cotentin peninsula on the other. The emphasis is upon the MS charts, Remark Books and notes etc. of the surveyors. The earliest survey discussed here is that of the Isles of Scilly by Capt Collins in 1689, published in 1693 in his Great Britain's Coasting Pilot, followed by Tovey and Ginver (1731), Robert Heath (1744/1750), Graeme Spence (1792-c1812) Joseph Huddart (1795); Ordnance Survey (Mudge: 1796; Clarke 1858; 1959). The first Channel Islands official hydrographic survey was initiated by Capt Martin White, as late as 1803, but not officially recognised until 1812 and not published until 1824/6; other surveys mentioned are Carte de France (1818-45; ) Begat (1829); Beck (1942-3); Service Hydrographique (1948); Ordnance Survey (1980).