in 1810, he published "a new method of conveying letters and goods with great certainty and rapidity by air", but did not patent the idea. this was followed in 1812 by his "calculations and remarks tending to prove the practicability, effects and advantages of a plan for the rapid conveyance of goods and passengers upon an iron road through a tube of 30 feet in area by the power and velocity of air". he also envisioned carriages running on rails, propelled by a continuous tube beneath the rails, as would later happened in the atmospheric railway. neither of these ideas was put into practical operation at the time. shortly before his death in september 1827 medhurst returned to the idea of pneumatic propulsion with his publication of "a new system of inland conveyance, for goods and passengers ... with the velocity of sixty miles in an hour ... without the aid of horses or any animal power." [with plates.]