The Barbican is a peculiarly picturesque structure commanding the entrance to the town on the south-east side by the ancient ferry across the river Stour, which at this point is tidal and often rapid and deep. There is a modern bridge. The gateway, which is flanked by two towers presenting externally semicircular walls, is largely of Tudor masonry, arranged in chess-board fashion in black flint and grey stone, and long flat bricks. On the southern side of the gateway a modern door has been made into the south tower. Splayed embrasures commanding the approach are visible within the tower. According to local tradition these were intended for cannon. The upper part of the gate is a modern restoration in woodwork. Sandwich originally possessed five gates, but those described are the only two which have survived. _Dover Castle._--For the last seven and a half centuries Dover Castle has been justly considered a fortress of paramount importance in the defence of England. Its site is remarkable for more than one reason. The steepness of the chalk cliffs towards the sea, and the abruptness of the other slopes, natural and artificial, which encircle it on the land side, give a peculiarly difficult, indeed, impregnable character to the fortress. The height of the hill on which the castle stands close to the narrowest part of the Channel which separates our shores from those of the Continent renders it a spot of unusual importance for the purposes of observing the approach of an enemy coming across the Straits of Dover. Although there are no certain traces of defensive works on the eastern heights of Dover before the time of the Norman Conquest, the natural advantages of the site, and Caesar's own words make it probable that some kind of camp or look-out post was established at Dover in prehistoric times. However, this is a matter of conjecture which lacks the confirmation of actual archaeological evidence. One of the first acts of the Norman Conqueror was to establish his power over the English by building earthwork castles, and such a work was thrown up on the eastern heights of Dover. Its form and extent are unknown, but it may, with reasonable probability, be conjectured that its central eminence was that upon which the keep was subsequently erected in the reign of Henry II. Dover Castle, as it exists to-day, presents a good example of the amalgamated defences of several different architectural periods. Its important position as the "Clavis et repagulum Angliae," gives it a national rather than local importance, and every part of it is of historical interest. As a fortress which from Norman times, almost without intermission to the present day, has retained its garrison and maintained a foremost place in the defence of the realm, Dover Castle deserves more than a passing notice in these pages.