John Griffiths, who wrote a biography[REF] of him in 1992, has argued that Watt's discouraging Murdoch from working with high pressure steam (Watt rightly believed that boilers of the time would be unsafe) on his steam road locomotive experiments delayed its development [REF].
Watt patented the application of the sun and planet gear to steam in 1781 and a steam locomotive in 1784, both of which have strong claims to have been invented by Murdoch [REF].