Water-Mill is a general term applied to all mills moved by the force or weight of water; many of the mills or machinery described in the course of this work would be popularly called by the indefinite term, water-mills. Now, the modes of communicating the impulse of water to the driving of machinery are various; some of these are described under the head Hydraulic-Machines; and amongst them one of great excellence, denominated the " Statical Hydraulic Engine;" and all that we have to add to the subject in this part of the work, will properly fall under the designation of Water-wheels, given in the subjoined article: as it is by the application of water-wheels that mills become water-mills.