In 1629, an Italian named Branca carried Hero's invention a step further, by inventing a simple apparatus whereby the revolution of Hero's hollow sphere was communicated to a series of pestles in mortars, and put to the useful work of compounding drugs. Branca seems entitled to the basic invention of the steam engine as an industrial machine. About 1663, the Marquis of Worcester invented a steam engine that exerted about two horse-power, and was employed to raise water from the Thames River, and supply it to the town of Vauxhall. Six years later (1669) Captain Thomas Savery erected a steam engine about twenty-five feet above the water in a mine, and successfully drew water out. This was a very important feat, because the difficulties surrounding the problem of freeing the mines from water were extremely great, and the desirability of overcoming them was equally so. In Savery's engine, there were two boilers in which steam was raised, and two receivers communicating with them. Steam being admitted to one receiver, the connection with the boiler was shut off by a valve, and a cold jet was then suddenly thrown on the receiver, condensing the steam and forming a partial vacuum. This vacuum the water below immediately rushed up to overcome. Connection with the pipe leading down was then shut off, and steam introduced to the receiver. This steam forced out the water from the receiver into a pipe, which discharged it above. This operation was then performed by the other boiler and receiver; so that, by their continued and alternate action, a fairly continuous stream of discharged water was maintained. This invention was quickly followed by Captain Savery with another, by means of which the discharge stream was made to fall on a mill-wheel, as though from a natural waterfall. Several of these machines were erected for actuating the machinery of mills and factories in the district. In 1690, Dr. Papin invented a steam engine, in which he used a cylinder containing water, with a piston so arranged that, when the water was heated, the steam would raise the piston. The fire being then removed the pressure of the atmosphere would force down the piston. This was followed shortly by an invention of Newcomer and Cawley, which was a very considerable advance on previous engines. It comprised a separate boiler and furnace, a separate cylinder and piston, means for condensing the steam in the cylinder by injecting water into it, and a system of self-acting valves that were opened and closed by a long beam that was moved by the piston. Furthermore, this beam communicated motion to a pump that pumped the water up directly. This engine was so efficient and so practically useful, that it was very generally introduced into service for draining mines throughout England. About 1775, Smeaton built an engine carefully designed on these lines, of which the cylinder was 72 inches in diameter, and the length of stroke was 10 feet and 6 inches.