On the opposite bank of the Thames is Tilbury Fort, the noted fortress that commands the navigation of the river and protects the entrance to London. It dates from Charles II.'s time, fright from De Ruyter's Dutch incursion up the Thames in 1667 having led the government to convert Henry VIII.'s blockhouse that stood there into a strong fortification. It was to Tilbury that Queen Elizabeth went when she defied the Spanish Armada. Leicester put a bridge of boats across the river to obstruct the passage, and gathered an army of eighteen thousand men on shore. Here the queen made her bold speech of defiance, in which she said she knew she had the body of but a weak and feeble woman, but she also had the heart and stomach of a king, and rather than her realm should be invaded and dishonor grow by her, she herself would take up arms. She had then, all told, one hundred and thirty thousand soldiers and one hundred and eighty-one war-vessels, but the elements conquered the "Invincible Armada," barely one-third of it getting back to Spain. Thus we have traced England's famous river from its source in the Cotswolds until it falls into the North Sea at the mouth of the broad estuary beyond Sheerness and the Nore. Knowing the tale of grandeur that its banks unfold, Wordsworth's feelings can be understood as he halted upon Westminster Bridge in the early morning and looked down the Thames upon London: its mighty heart was still and its houses seemed asleep as the tranquil scene inspired the great poet to write his sonnet: "Earth has not anything to show more fair; Dull would he be of soul who could pass by A sight so touching in its majesty: This city now doth like a garment wear The beauty of the morning; silent, bare, Ships, towers, domes, theatres, and temples lie Open unto the fields and to the sky; All bright and glittering in the smokeless air. Never did sun more beautifully steep In his first splendor valley, rock, or hill; Ne'er saw I, never felt, a calm so deep! The river glideth at his own sweet will; Dear God! the very houses seem asleep, And all that mighty heart is lying still." V. LONDON, NORTHWARD TO THE TWEED.