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versant. Ring-bolts should be set in the stonesused for moorings; and this, indeed, is indis-pensable, where hempen cables are used, be-cause these would soon be chafed through bythe edges of the stone. The ordinary way offixing ring-bolts is to set them, by melted lead;but then they cannot easily be removed. Figure13, plate 8, shows an ingenious and simplemethod of fixing ring-bolts in stone, from whichthey may be taken out with great facility. Adove-tailed mortise is cut in the stone, largeenough to receive the three pieces of iron A C,B I), and G. The dove-tailed pieces are firstplaced in the mortise; the centre piece, G, isthen set between them, and the shackel Efastened to the three, by the bolt F whichpasses through them all. A few such ring-bolts should always be provided, together withany other stores and materials which may befurnished for the contingencies of service. Butring-bolts, set in this way, cannot be removedwithout weighing the stone to which the chainis attached. When, therefore, heavy stones areto be used as moorings, or when there may beany other occasion for lowering into, and layingthem in deep water, the central part, A, fig. 14,of the three pieces which are to be let in to thedove-tail space, should have the ring and chain