""Theatrum machiuamm universale," &c. by Jacob Leupold, Leipsic, seven volumes, folio, 1724, 1727,1774. This is the greatest and most complete work of this kind that ever was published. The first volume is little more than an introduction to the work; the second and third volumes contain a description of hydraulic machines; the next two volumes relate to machines for raising weights, the theory of levelling, and other subjects; and the sixth treats principally on machines connected with the construction of bridges; the seventh volume is entitled, "Theatre arithmetico geometrique," where the author treats of all instruments employed in these two sciences This work would have been much more considerable if its author had lived to complete the immense task he had undertaken."