When rats have once found their way into a ship, they are secure as long as the cargo is on board, provided they can command the great necessary--water. If this is well guarded, they will resort to extraordinary expedients to procure it. In a rainy night they will come on deck to drink, and will even ascend the rigging to sip the moisture which lies in the folds of the sails. When reduced to extremities, they will attack the spirit-casks and get so drunk that they are unable to walk home. The land-rat will, in like manner, gnaw the metal tubes which in public-houses lead from the spirit-store to the tap, and is as convivial on these occasions as his nautical relation. The entire race have a quick ear for running liquid, and they constantly eat into leaden pipes, and, much to their astonishment, receive a douche-bath in consequence. It is without doubt the difficulty of obtaining water which causes them in many cases to desert the ship the moment she touches the shore. On such occasions they get, if possible, dry-footed to land, which they generally accomplish by passing in Indian file along the mooring-rope, though, if no other passage is provided for them, they will not hesitate to swim. In the same manner they board ships from the shore, and so well are their invading habits known to sailors, that it is common upon coming into port to fill up the hawser holes, or else to run the mooring-cable through a broom, the projecting twigs of which effectually stop the ingress of these nautical quadrupeds. Their occupancy of the smaller bird-breeding islands invariably ends in their driving away the feathered inhabitants, for they plunder the nests of their eggs, and devour the young. The puffins have in this way been compelled to relinquish Puffin's Island, off the coast of Caernarvon.