By the middle of the eighteenth century, the Channel had become one of the busiest waterways in the world, with the ports of Bristol, Liverpool, Dublin and Waterford growing rich on the Atlantic trade in sugar and slaves, and the burgeoning industrial revolution.

This beautiful chart "engraved on Six sheets of large Elephant Paper" was at the time of printing the largest and most accurate chart of the St George's Channel. The chart not only contains information on soundings, sand banks, and the times of the tides, but also depicts the defeat of the Francois Thurot, Captain of the 'Maréchal de Belle-Isle', who had been terrorizing British interests since the start of the Seven Years War. Thurot met his end at the hands of HMS Pallas, HMS Brilliant, and HMS Aeolus, who caught up with him off the northern coast of the Isle of Man; during the action Francois Thurot was killed by a musket ball and his body thrown overboard. Also depicted is the 'Author [Captain Robert Williamson] Ship Wreck't [sic] Jan. 21. 1748 occassioned by the Errors of the Drafts then Extant' at Dundran Bay on the Irish coast. Little is known about the author of the chart, Captain Robert Williamson, save that he was a captain of some considerable experience of St George's Channel; and who saw, from bitter personal experience, the need for its accurate charting.

We are only able to trace two institutional examples, one in the British Library and the other in the Bibliothèque Nationale de France.