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PREFACE.

The third Book begins with a very extensive dissertation on the properties of air; in what manner water rises by suction original: "afpiration"; the process of creating a vacuum to allow atmospheric pressure to push water upward.; the use that can be made of the expansion and condensation of air; the force that its elasticity original: "reſſort"; literally "spring," a term used by early scientists like Boyle and Bélidor to describe the pressure exerted by compressed air. acquires through heat to move machines, derived from experiments made in France and England. This may serve as an introduction to Physics original: "Phyſique"; in the 18th century, this referred to "Natural Philosophy" or the study of the laws of nature., and to explain the effects of suction pumps and machines for raising water by means of fire. This dissertation is followed by the method of calculating the force of the wind, and the advantage that can be drawn from it to drain a waterlogged country or to irrigate arid land, for which examples are provided.

Next, the properties of all the pumps that have been devised until now are described: their defects and advantages are shown, and to what degree of perfection they can be brought. A circumstantial detail has been entered into regarding all their parts, principally the pistons and valves original: "Piſtons & les Soupapes".; this has been done with all the more care as it appears this subject has not yet been seriously examined.

After having considered the pumps in themselves, a great number of machines for moving them are reported; some for the use of private individuals, in which I include those used for fires original: "incendies"; early hand-pumped fire engines were a major technological advancement for urban safety.; others suitable for maintaining the fountains of a city. Examples are given of the finest currently in operation in various parts of Europe, set in motion by animals, the flow of rivers, and the force of fire. These last were recently invented by the English A reference to the early steam engines of Thomas Savery and Thomas Newcomen, which Bélidor was among the first to describe in detail in France., who knew how to draw from fire the most powerful agent in nature and manage it with such art that what they have done in this regard can be looked upon as the masterpiece of the human spirit; therefore, I have spared no effort...