which also described the difficulty of navigating the Firth for sailing vessels.  This informed us that “the current in the Pentland Firth is exceedingly strong during the spring tides, so that no vessel can stem it.  The flood-tide runs from west to east at the rate of ten miles an hour, with new and full moon.  It is then high water at Scarfskerry (about three miles away from Dunnet Head) at nine o’clock.  Immediately, as the water begins to fall on the shore, the current turns to the west; but the strength of the flood is so great in the middle of the Firth that it continues to run east till about twelve.  With a gentle breeze of westerly wind, about eight o’clock in the morning the whole Firth, from Dunnet Head to Hoy Head in Orkney, seems as smooth as a sheet of glass.  About nine the sea begins to rage for about one hundred yards off the Head, while all without continues smooth as before.  This appearance gradually advances towards the Firth, and along the shore to the east, though the effects are not much felt along the shore till it reaches Scarfskerry Head, as the land between these points forms a considerable bay.  By two o’clock the whole of the Firth seems to rage.  About three in the afternoon it is low water on the shore, when all the former phenomena are reversed, the smooth water beginning to appear next the land and advancing gradually till it reaches the middle of the Firth.  To strangers the navigation is very dangerous, especially if they approach near to land.  But the natives along the coast are so well acquainted with the direction of the tides, that they can take advantage of every one of these currents to carry them safe from one harbour to another.  Hence very few accidents happen, except from want of skill or knowledge of the tides.”

[Illustration:  A NORTH SEA ROLLER.]

There were some rather amusing stories about the detention of ships in the Firth.  A Newcastle shipowner had despatched two ships from that port by the same tide, one to Bombay by the open sea, and the other, via the Pentland Firth, to Liverpool, and the Bombay vessel arrived at her destination first.  Many vessels trying to force a passage through the Firth have been known to drift idly about hither and thither for months before they could get out again, and some ships that once entered Stromness Bay on New Year’s Day were found there, resting from their labours on the fifteenth day of April following, “after wandering about like the Flying Dutchman.”  Sir Walter Scott said this was formerly a ship laden with precious metals, but a horrible murder was committed on board.  A plague broke out amongst the crew, and no port would allow the vessel to enter for fear of contagion, and so she still wanders about the sea with her phantom crew, never to rest, but doomed to be tossed about for ever.  She is now a spectral ship, and hovers about the Cape of Good Hope as an omen of bad luck to mariners who are so unfortunate as to see her.