John McFarlane Gray

He left home and moved to Edinburgh where he worked as an apprentice while studying the Hebrew and Greek languages, mathematics and mechanics.

His employers recommended him for a position as chief draftsman and manager at the George Forrester and Company engineering works in Liverpool.

At that time as many as a hundred men might be needed to work the steering gear in an armoured cruiser moving at full speed.

[3] Gray said of the steering device much later, The principal thing that I did was to make an automatic controlling valve, continuous in its action.

As the rudder approaches the desired angle indicated by the helm the steam valve is adjusted to reduce power.

He said, "If engineers will aim at so conducting themselves that they are never spoken of otherwise as being 'quite equal if not superior to the deck officers in their language and behaviour', and if that pertains to their highly intellectual calling that makes themselves masters both of theory and the practice, the time would not be very distant when their importance in steamers would be fully recognized.

"[9] Gray was employed by the Board of Trade in Liverpool, then in Cork and finally in London, where he was appointed chief examiner of marine engineers.

[10] Macfarlane Gray was instrumental in introducing the use of entropy-temperature diagrams, described by Professor Josiah Willard Gibbs, for solving steam engine problems.

However, he read papers on the subject before the Physical Society and the Institution of Naval Architects, and planned to publish a book giving the results of his researches into thermodynamics.