Forth bridge painting

The Forth Bridge as painted by William Lionel Wyllie in 1914.

William Murdoch

1754 – 1839

William Murdoch

mechanical and gas engineer, Boulton & Watt partnership

Engineering Achievements

William Murdoch was a Scottish mechanical and gas engineer. He started work with his father, a miller and millwright at Lugar, Ayrshire after leaving school in Cumnock. His father is believed to have been the first millwright to use cast-iron gearing. In 1777 he went to Birmingham and secured employment with Boulton and Watt, where he worked closely with James Watt on both his pumping and rotative steam engines. He remained in employment with the Boulton and Watt partnership, and its succeeding company until his retirement in 1830. He was largely responsible for the development of gas lighting, and probably of pioneering marine steam engines. Some of his other inventions also found applications in Scotland.

In his early years with Boulton and Watt he was their engine erector in Cornwall, one of the firm’s best markets. In this he proved very successful. He also worked with Watt on the development of the rotative steam engine and devised the ‘sun and planet’ gearing which was critical to its success.

While in Cornwall he devised, from 1781, a series of small model high-pressure non-condensing steam road locomotives. Watt patented Murdoch’s concept, but would not allow him to develop the idea formally. Informally he continued this development; his 1791 version almost certainly influencing the work of Richard Trevithick in developing full-sized road carriages and railway locomotives. Murdoch later devised the slide valve for steam distribution, a device used for many years in locomotives, stationary and marine steam engines. The last main-line steam locomotives in use in Scotland in the 1960s were fitted with slide valves.

He also invented the oscillating engine in 1785, a form of engine later extensively used for marine propulsion.

He was almost certainly the inventor of the ‘small side-lever’ engine, one of which Boulton and Watt and Sons supplied to Robert Fulton for his pioneering steamboat Clermont, the first commercially successful vessel of the type. The engine of Henry Bell’s Comet was a version of the type, and it was developed by David Elder and others to power the largest steamships until the mid-1850s.

He designed large precision tools for the Soho Foundry which were prototypes for subsequent machines installed in the largest class of mechanical engineering. He also devised systems for using compressed air and vacua to transmit power, and used them in the Soho works from 1798.

He famously developed successful apparatus for generating and purifying coal gas, and for using it for illuminating factories. This provided the basis for public gas distribution. He was reputedly prevented from gaining full credit for his creative achievements by the attitude of his employers, though he remained friendly with James Watt until his death.

His Life

  1. 1754 Year of birth
  2. 1777 Started working at Boulton and Watt
  3. 1781 Devised a series of small model high-pressure non-condensing steam road locomotives
  4. 1785 Invented oscillating engine
  5. 1839 Year of death

His Legacy

Murdoch’s most famous legacy is his work on gas lighting. It is however reasonable to argue on the basis of fragmentary evidence, that he made a major contribution to the success of Watt’s condensing engines, and hence to the widespread adoption of steam power.

It is also fair to argue that Murdoch’s experimental engine, demonstrated in Cornwall led directly to the work of Trevithick, and through that to Goldsworthy Gurney’s steam carriage (which used Murdoch’s slide valves), and then to the horizontally disposed cylinders of Robert Stevenson’s Planet locomotive, the ancestor of many subsequent railway locomotives, and a component of the ‘Stevenson Railway’ which was internationally influential.

There can be little doubt that, as described above, the Soho Foundry, under the direction of Murdoch, produced the first successful type of marine steam engine. The direct legacy of this particular layout was limited to a few decades, but the impact of the success of steam navigation which they demonstrated has repercussions which continue to this day. Though the manufacture of coal gas explicitly for lighting is now obsolete, it was Murdoch’s process that made the general use of fuel gas practicable, again with repercussions which continue.

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