ABSTRACT
I N the metal as in the textile industry, most of the inventions on which modern technique is based were the result not of abstract speculation but of practical necessity and professional experience. With the steam engine science first made its appearance, and the empirical period of the industrial revolution was followed by the scientific one. This is one of the facts which account for the capital importance of this invention, as it forms a part of the history of science as well as of technology. But it is no part of our plan to study it from this double point of view, for which the knowledge both of the physicist and of the engineer would be needed. We must limit ourselves to drawing on the recognized authorities for the elementary data needed to understand the facts which belong to our own field of study. For the purposes of the present book the discovery of steam-power is an economic phenomenon. What need called forth the discovery, and how did it materialize? When was the steam engine introduced into various industries, giving rise at the same time to a wholly new industry? These are the questions to which an answer can and must be found. Documents of first-rate importance are available: those from Boulton and Watt's works in Soho,l the greater part of which have been fortunately preserved owing to the enlightened interest of a great industrial firm.2 They enable us to reconstruct the industrial and commercial history of the steam engine at its first critical stages.
