Mr. Reid on Writing-ink, S^c. Ill 



attached, and the chain must be of sufficient length to allow 

 the buoy to rise to the surface at high water. 



In most anchorages the weight of the cast-iron block will 

 sink it sufficiently deep to prevent its being moved; but in 

 stiff ground, where that may not take place, piles must be 

 driven round it, by means of the diving-bell, so as effectually 

 to secure it. 



It is conceived that a buoy of these dimensions would be 

 sufficient to hold a ship of 500 tons under any circumstances ; 

 but for a very large vessel, the size of the cast-iron block and 

 also that of the buoy would require to be considerably in- 

 creased, as the larger the buoy, with the greater ease would the 

 vessel ride. 



The principal cause of a vessel dragging her anchor, or 

 parting her cable in a gale of wind, is the jerk that is produced 

 by a heavy sea strikuig her when the cable is on the stretch. 

 By the proposed plan this would be guarded against; as the 

 tendency of the buoy to rise perpendicularly, while the vessel 

 pulled horizontal!}', would cause a spring on the cable so as 

 to prevent any sudden jerk. A vessel moored in this manner 

 would probably not require to veer out more than 20 or 30 

 fathoms of cable: and the manner of bringing up would be, to 

 make fast a hawser to the buoy : heave upon it until the latter 

 came under the bows of the vessel, then pass the (chain) cable 

 through the ring of the buoj', and bring the end on board. 

 The cable would thus be double, and a vessel could get under 

 weigh in an instant by letting go one end of it. 



Buoys of this description might be laid down (in the Downs 

 for instance) in Hues at different distances from the shore; and 

 a vessel, instead of looking out for good holding ground, might 

 then bring up as near to the land as her draught of water 

 would permit her, and thus facilitate her communication with 

 it. They might also be laid down in rocky ground, where 

 ships cannot anchor at all, by attaching them to bolts fixed in 

 the rocks, by means of the diving-bell. 



XXI. On fVfiting-ink, and on the Effects 'which are produced 

 upon it by Paper and Parchment. By Mr. John Reid.* 



IT has often been remarked that old writings retain their co- 

 •^ lour better than those of a later date ; and it has been sup- 

 posed in consefjuence, that ibrmerly, ink of a superior quality to 

 that now in use had been employed. But though much depends 



* ('oninniiiit:»lc(l l)y the Author. 



upon 



