This appointment he resigned in 1837, removing in the following year to Vanbrugh Castle, Blackheath, where he established an institution for the treatment of spinal diseases.
His increasing interest in his inventions diverted his attention from his patients, and Vanbrugh Castle was eventually given up.
9642) for conveying letters on a railway formed by suspending wires or light rods from distant points, making use of church towers, or any other lofty structures available.
It consists in the sinking of hollow piles of iron, open at the lower end and closed at the top by a cap.
The pile descends by its own gravity, assisted by the pressure of the air on its closed end, and when it is filled, the contents are discharged by a pump.
Potts gave evidence on 10 June 1844 before the royal commission on harbours of refuge (cf.
Report, p. 119), when Mr. James Walker, president of the Institution of Civil Engineers, and a member of the commission, spoke very highly of the new method.
The first large work upon which it was employed was the viaduct which carries the Chester and Holyhead railway across Maeldreath Bay in the Isle of Anglesey.
Nineteen tubes, one foot diameter and sixteen feet long, were successfully sunk in the sand during the summer of 1846.
The foundations for the South-Western railway bridge over the Thames, between Datchet and Windsor, were laid by Potts's method; but on 12 August 1849, when the line was ready to be opened, one of the tubes suddenly sank, causing a fracture in the girder resting upon it (Times, 14 Aug. 1849, p. 3).
G. W. Hemans tried it with cylinders ten feet diameter in 1850, during the construction of a bridge over the Shannon at Athlone, on the Midland Great Western railway of Ireland, but the expense of pumping out the air was very considerable, and much trouble was caused by boulders, which the trial borings had failed to indicate (cf.
180, 247; Civil Engineers' and Architects' Journal, December 1850, p. 392; Burnell's Supplement to Weale's Theory of Bridges, 1850, p. 100).
Potts read a paper on his method before the Society of Arts on 10 May 1848, for which he received the Isis gold medal (Transactions, lvi.
Four daughters and two sons, John Thorpe and Benjamin L. F., both of whom were trained as engineers at the London Works, Smethwick, near Birmingham, under Fox & Henderson, survived him.