When the Armada came, John Davis was appointed to the command of a vessel of 20 tons, the _Black Dog_, to act as a tender to the Lord Admiral, with a crew of ten men and an armament of three guns. Here Davis was of use to the flagship as a pilot, for no one had taken more intelligent interest in surveying the coast and marking shoals than he. We need not go again through the events of the long fight, but it was in the fight off the Isle of Wight that Davis saw the fiercest action, when Admiral Oquendo in his flagship, of 900 tons, rammed the stern of the English flagship, the _Ark Royal_, and unshipped her rudder. After ten days of severe work Davis returned to Plymouth, and was at home when his fourth child was born, named Philip! Another memorial of the Armada times was a work on navigation, written by Davis and dedicated to Lord Howard of Effingham. The next employment Davis found was to join the Earl of Cumberland's squadron in the _Drake_ off the Azores, where he probably met Edward Wright, an eminent mathematician and cosmographer, who had gone to sea to observe the practical working of problems in nautical astronomy. Davis himself had invented an instrument for observing the stars, so these two had much to discuss in common. It was on this voyage that the English crews suffered so much from want of water, which was very scarce on the islands. The natives on Graciosa, on being asked for water, replied that they would rather give two tons of wine than one of water. They came home with thirteen prizes, and the money Davis received as his share enabled him to go on an expedition more to his taste; for he loved peaceful knowledge better than fighting. His scheme was to go through Magellan's Straits, to navigate the South Sea, and discover the North-west Passage from the western side. Magellan, a Portuguese navigator, had only discovered the strait called by his name seventy years before; it was in 1520 that Magellan first sailed in and found very deep water. As he passed along, winding to and fro, he saw so many fires at night lighting up the woods and rocks on the southern side of the strait, that he named the land "Tierra del Fuego." A snowy peak far to the south he named "Campana de Roldan," "Roldan's bell"; they were short of provisions, and the crew murmured and wished to return, but Magellan, a stern disciplinarian and feared by his men, swore they should eat the chafing-mats on the rigging rather than return. After thirty-seven days of sailing through winding reaches that seemed to lead nowhere, and that stretched a hundred leagues and more, they came out into the South Pacific; then boldly striking across the ocean to the islands of the far East, Magellan met his fate at the hands of ruthless savages.