constructing the docks and basin he made pioneering use of Smeaton's waterproof cement. He also designed a "ship caisson" to close off the entrance to the basin (another innovation which soon became a standard design). To deal with the increasing number of docks, Bentham in 1797 proposed replacing one of the horse pumps above the reservoir with a steam engine. His plan was that the engine should be used not only to drain the reservoir (by night) but also to drive a sawmill and woodworking machinery (during the day); he also envisaged linking it to a freshwater well, to enable water to be pumped through a network of pipes to various parts of the dockyard. A table engine, designed by Bentham's staff chemist James Sadler, was installed in 1799; it represented the first use of steam power in a Royal Naval Yard. By 1800 a second steam engine (a Boulton & Watt beam engine) was being installed alongside the first. Meanwhile, Bentham designed and built a series of subterranean vaulted chambers over the reservoir, upon which he erected a pair of parallel three-storey workshops to contain reciprocating and circular saws, planning machines and morticing machines, built to his own designs, to be driven by the two engines (which were accommodated together with their boilers in the south workshop). Tanks installed on the upper floor provided a head of water for Bentham's aforementioned dockyard-wide pipe network, providing both salt water for firefighting and fresh water for various uses (including, for the first time, provision of drinking water to ships on the wharves) sourced from a newly sunk 274 ft well. Between the two Wood Mills buildings a single-storey workshop was built in 1802 to accommodate what soon came to be recognised as the world's first steam-powered factory for mass production: Portsmouth Block Mills. Marc Brunel, father of Isambard Kingdom Brunel, famously designed the machines, which manufactured ships' pulley blocks through a total of fifteen separate stages of production. Having been presented with Brunel's designs, which would be built by Henry Maudslay, Bentham incorporated them into his woodworking complex and linked them to the engines by way of line shafts. At the same time as building his Wood Mills, Bentham, with his deputy Simon Goodrich, was constructing a Metal Mills complex a little to the north-east. Alongside a smithery were a copper-smelting furnace and refinery, and a steam engine which drove a