In 1771, work had begun on the Chesterfield Canal, but while surveying a new branch of the Trent and Mersey between Froghall and Leek, Brindley was drenched in a severe rainstorm. It had happened many times before, but he was unable to dry out properly at the inn at which he was staying, and caught a chill. He became seriously ill and returned to his home at Turnhurst, Staffordshire, where Erasmus Darwin attended him and discovered that he was suffering from diabetes.