ix

PREFACE.

...of interesting theory and practice in these kinds of Machines; it also shows how one can use the ebb and flow original: "flux & reflux"; referring to the use of tidal power to drive machinery. of the sea to make wheels always turn in the same direction, the manner of constructing hand-mills, and others set in motion by horses for the use of fortified places original: "Places de Guerre"; military garrisons or strongholds where manual or animal power was necessary when water or wind was unavailable..

Next, sawmills are described, an analysis is made of all the parts that enter into their composition, and the output is calculated according to the thickness of the pieces of wood that one wishes to cut; others are also mentioned for sawing stone blocks, others for boring wooden pipes for the transport of water; finally, others for pulverizing materials, such as, for example, those used in the composition of gunpowder original: "Poudre à Canon"; Bélidor was a military engineer, making the production of gunpowder a primary concern..

All these mills are accompanied by research on what can make them perfect, along with calculations that encompass friction original: "frottemens"; the resistance encountered when one body moves over another, a critical concept in early mechanical engineering. and all the accidents inseparable from practice, which have been subjected to rules so clear and so palpable that with moderate attention, the reader can imperceptibly acquire knowledge that will give him an enlightened understanding of all sorts of machines.

Chain pumps original: "Moulins à Chapelet"; literally "rosary mills," these machines use a series of buckets or discs on an endless chain to lift water. being rightly regarded as the most convenient machines for drainage original: "épuiſemens"; specifically the removal of water from foundations, mines, or cofferdams., all sorts of species have been reported with calculations of the force necessary to set them in motion, and the output of which they may be capable. When they act on inclined planes, it is shown what angle the plane must form with the horizon so that the chain pump drains as much water as possible in a determined time. The effect of these chain pumps is compared with that of several other machines for the same use, to show which of them should be preferred. Finally, several types of water wheels are described, either for drainage or for lifting water into a reservoir.