[Untitled manuscript chart of the South China Sea]

A rare example of a manuscript sea chart from the Thames School, with intriguing early annotations. The chart shows southern Formosa, the south coast of China, Indochina, and the western Philippines. It dates from the late 17th or early 18th centuries. The annotations (c.1720) suggest that it was a working copy, perhaps used in the offices of the British Navy.
According to Thomas Smith, the Thames School emerged at the close of the sixteenth century. The early chartmakers closely followed the medieval tradition of portolan making. Charts were usually drawn on vellum on a relatively small scale, elaborately ornamented, and brightly colored. Almost all of these early Thames School charts were devoted to the Mediterranean, western Europe, or the Atlantic.
After about 1680, the Thames School increasingly turned its attention towards Oriental Navigation. This shift in geographical emphasis was accompanied by stylistic changes.
Portolan-style charts were gradually superseded by large-scale pilot charts, with paper an increasingly common medium. Decoration and color became more subdued. Standard delineations for specific geographic features were developed, which indicated "a mutual awareness of common sources, if not actual collaboration" between the chartmakers (Smith, p.60).
This chart is closely related to the work of John Thornton, the most notable of the late Thames School chartmakers. Smith reproduces a Thornton chart of the Gulf of siam dated 1699 (fig.12), which in turn was based on one of the same area from 1664 by Joan Blaeu (fig.13). In southern Indochina, where the coverage of these charts overlap with this one, the geography is identical. In all probability, our chart is a slightly later version of a 1699 Thornton chart of the South China Sea in the collection of the Bibliotheque Nationale, Paris. According to La Roncière, this chart also derived from a Blaeu prototype. This chart is clearly an example of the Thames School's "standard delineation" for the south China Sea, related to earlier Dutch and English prototypes, but updated to account for new information.
Also of the same type is a large Thames chart in the Newberry Library (Ayer ms 125), "Made by Robert Friend, hydrographer in Shafts Court over against ye East India House in eaden Hall Street, London 1719". According to sources at the Newberry, Friend's chart is beautifully colored, on two sheets of vellum, and was a library as opposed to a working copy. This chart is clearly of the latter type. It shows the vicissitudes of use, and has a number of slightly later annotations that take the form of corrections.
Just to the west of the site of Hong Kong is an island labeled "Grand Ladrone". To the southwest, near Macao, is an island labeled "Pulo Saby". Near "Grand Ladrone" is a notation that reads: "I do not think the Grand Ladrone lies so far to the Eastward of Pulo Sapata by 8 or 10 Leagues as this draught makes it."
At center is a small shoal labeled "Discovered Anno 1678, with its depth given as 10 fathoms. Below is a notation: "I saw the ground under us in 1716 and think we had not above 9 fathom at one cast of the Lead."
At lower center there is a small island or shoal named "Pedra Vigia". To the east is an island called "Pedra Dandrada". Near "Pedra Vigia" is a notation that reads: "Near this same Meridian it is certain there is Rock but I am of Opinion that Pedro dandrada & this call'd Vigia are the same as a that there is but one Rock which hath been seen by Persons whose Meridian distance have not been taken from the same Place and whose Accounts have therefore differ'd in Placing the said Rock however a good [-?-] for both is always [-?-]".
At lower left center there is an island, "Pulo Sapata". Below is a notation that reads: "Cap. Hill was very positive he saw a Rock bearing ESE from Sapata 7 miles distance".
This chart may have been used on board ship. Or it may have been a working office copy, used by the Navy Board, or some other agency. At any rate, it was corrected and updated in about 1720 with new information supplied by one or more English sea captains familiar with Oriental Navigation. It therefore demonstrates the working method of the Thames School chartmakers of the seventeenth and eighteenth centuries.
Thomas R. Smith, "Manuscript and Printed Sea Charts in Seventeenth-Century London: The Case of the Thames School", The Compleat Plattmaker, pps. 45-99; Monique de la Ronciere, "Manuscript Charts by John Thornton, hydrographer of the East India Company (1669-1701)", Imago Mundi, 19 (1965), pp. 46-50.