seen one, invented by him for driving piles, which acts by a motion always in the same direction, without being obliged to stop or to retrograde, in order to raise up again the weight. Nothing, in our opinion, can be so ingenious as the method in which, after the fall of the weight or rammer, the hook, that serves to raise it again, lays hold of it, and by which the cable lengthens itself in order to reach lower and lower in proportion as the pile sinks deeper. If this mode of construction be compared with those hitherto employed, no one can refuse to give it the preference. There is also the Collection, in 6 vols. 4to, of Machines and Inventions approved by the Royal Academy of Sciences, containing the engravings and descriptions of a great multitude of machines. In English too we have Desaguliers's Course of Experimental Philosophy, in 2 vols. 4to. also Emerson's Mechanics, both containing the figures and descriptions of many curious and useful machines, Besides some others, of less note, A TABLE Of the Specific Gravities of different bodies, that of rain or distilled water being supposed 1000. carats fine, not hammered * 17486 The same hammered Gold of the standard of French coin, 214 carats fine, not hammered The same coined. Gold of the French trinket standard, 20 carats fine, not hammered The same hammered 17589 17402 17647 15709 15775 |