A new and accurate map of the county of Cornwall : from an actual survey. London : Robt. Sayer, 1748. Christophe Daniel Ebeling Collection, no. 2448. Gift of Israel Thorndike, 1818.
Thomas Martyn was a Cornish surveyor who earned his daily bread by mapping out the estates of prosperous landowners. His extensive travels over the course of more than a decade gave him the opportunity to undertake a much more ambitious project—a large-scale (one inch to the mile) survey of the county, which he published in 1748. The completion of such a monumental project required considerable financial support. As with other county mapping projects in England in the 18th century, the primary mechanism for underwriting the surveyor’s time and the publisher’s expense was the subscription system. Martyn’s map (printed on 9 sheets) could be purchased for the princely sum of three guineas. Subscribers paid part of the cost in advance, and the remainder upon receipt of the map. Those who wanted their coats-of-arms engraved in the border of the survey and their county seats noted on the map paid extra for that privilege (164 subscribers took advantage of that offer).