This paper explores the tentative steps towards power comparisons in the early to mid 18th century, focussing on the mathematisation of wind and water power, and the attempts to ground this old technology into a new Lockean philosophy. In particular it will consider the work of John Theophilus Desaguliers, but also touch on that of Colin McLaurin, Daniel Bernoulli and others. It will consider the establishment of the authority of measurement, the search for common measures of power between men, horses and machines. It will look at the impetus to bring this area of technology under a consistent mathematical umbrella, imposing order on a range of previously unrelated activities. It will also demonstrate the emerging role of mathematics in contrast to craft skills, sometimes supportive, sometimes challenging, but relying on a new approach to old issues. Desaguliers marks out the boundary of his territory thus in 1734: ‘Neither do I here take notice of …… any of the laborious operations of handy-craft trades because some men are much more dextrous than others and the same man by long use becomes so perfect in one way of working, that by an acquired sleight of hand he shall do twice the work that an inexperienced person can do, and yet not employ half so much strength, but this is properly craft and not labour which last was all I meant to consider here’. However, while he did not want to stray into territory over which there was little control, the rapid increase in the use of machines, largely relying on water power, meant he and his contemporaries were in a position to exert influence, in spite of the uncertainty regarding fundamental concepts and the lack of closure regarding the application of mathematics. The connection between the measurement and the mathematisation is complex in this period, and as expected, does not follow the suggested path of Whig history or the Platonic ideals of the ‘scientific method’. The paper will be illustrated by models and archive material from the collection in the Science Museum, London, some used to demonstrate direct comparisons between different power sources. The contemporary models will be viewed in the light of the dissemination of experimental philosophy in the early to mid 18th century, and its connection with the developing technology. Later models will be contrasted as items in a museum setting for the general consumption of scientific principles.