Jonathan Williams | Presentation copy of Franklin's grandnephew's work on thermometrical navigation

Jonathan Williams

Thermometrical Navigation. Being a Series of Experiments and Observations Tending to Prove that by Ascertaining the Relative Heat of the Sea-Water from time to time, the Passage of a Ship through The Gulf Stream, and From Deep Water into Soundings, may be discovered in time to Avoid Danger... Philadelphia: R. Aitken, 1799

8vo (228 x 135 mm, uncut). Typographic tables in text, errata on p. 89, 4-page postscript, and untitled folded engraved map at rear; with light toning, intermittent spots, light dust-soiling at upper corner, the title with a small chip and a strip of toning along the tail edge, the folding map with chipping and dust-soiling along the outer edge and with a tiny hole along a fold neither affecting the printing. Modern quarter calf, gilt spine, marbled paper boards; edges lightly rubbed.

A presentation copy of the first edition of this scientific treatise on thermometrical navigation, penned by Benjamin Franklin's grandnephew, Jonathan Williams and inscribed "from the author" on the title-page.

Williams worked as Franklin's personal secretary in London and Paris from 1770 to 1783, before enjoying a long military career and a stint as a representative in Congress. In this work, he builds on his great-uncle's earlier research into the Gulf Stream, and establishes a practical usage for it. Williams had previously published parts of this treatise in The Proceedings of the Philosophical Society in 1786 and 1793, but this is the first complete publication.

The goal of thermometrical navigation was to use the ocean's surface temperature to identify its currents. A navigator could then optimize his route, establishing certain facts about a ship's position without the aid of the stars, which are often hidden by clouds. Williams points out that water is colder nearer to the shore and warmer in the gulf stream. As such, keeping abreast of water temperature could help a mariner avoid running aground on a dangerous bank, even if he had been taken off his course by faulty reckoning or an unforeseen current.

The folding map at the rear recalls Franklin's earlier map of the Atlantic currents (see lot 124). Williams's map, however, covers a larger geographic area, showing the entirety of the Atlantic. It also includes the tracks of five different ships and shows measurements of ocean temperatures at various locations along their routes. This is the third state of the map (though Wheat and Brun identify it as the second), with the shading for the Gulf Stream extended and additional directional arrows added.

REFERENCES

ESTC W7573; Evans 36722; Sabin 104300; Wheat and Brun 725 (for the map)

PROVENANCE

Presentation inscription "from the author" to an unnamed recipient, presumably to The Royal Institution, which was founded that year (ink stamp on the verso of the title-page)