Perhaps the most famous explorer was Christopher Columbus. Like all learned men of his time, Columbus knew the world was round. He theorized that since the Earth was a sphere, a ship could eventually reach the Far East from the opposite direction. He envisioned trade routes to Asia. The fifteenth-century Europeans were not aware of the South and North American continents. Maps were not accurate and no one knew there was a Pacific Ocean. King Ferdinand and Queen Isabella of Spain agreed to give him ships and a crew. He set sail in 1492. Columbus promised to bring back gold, spices, and silks from the Far East, to spread Christianity, and to lead an expedition to China. In return, Columbus asked for and got the hereditary title "admiral of the ocean seas." Columbus' ships covered approximately 150 miles a day. His seafaring instincts were extraordinary. His crews used a compass for direction and a chip log (a knotted line with a wooden weight attached at the end) to measure speed. A sailor counted how many knots were let off the reel in the time allotted. Multiplying the average rate of a ship's speed by a fixed amount of time gave a rough estimate of the distance traveled. Columbus, however, relied on dead reckoning, meaning he used his experience, intuition, observations, and guesswork to determine his ships' positions. |
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