118 THE OCEAN RIVER 



at least a hundred miles farther east. The wreck resulted in the 

 loss of four ships and over 2,000 seamen besides the admiral. 

 Such losses as this, which could have been prevented if a 

 method had been available for measuring longitude at sea, 

 finally persuaded Parliament in 1714 to pass a bill offering 

 £20,000 for an instrument which would be accurate to within 

 two minutes of time, which is equal to about 30 miles at the 

 equator. 



Many fantastic solutions were proposed. One, mentioned in 

 Lloyd A. Brown's The Story of Maps, is typical. It involved 

 the use of a popular remedy prepared by Sir Kenelm Digby 

 known as the ''powder of sympathy." The original purpose of 

 this nostrum was to cure wounds by the imaginative method 

 of applying it not to the wound but to the weapon which had 

 inflicted it. The physician also declared that by merely placing 

 a dressing from a patient's wound in contact with the powder 

 he could cause the patient to jump. The would-be inventor of 

 a longitude method suggested in all seriousness that every ship 

 before sailing be provided with a wounded dog. On shore a 

 trustworthy collaborator, equipped with a good clock and a 

 bandage from the dog's wound, would each hour, exactly on 

 the second, dip the bandage in the powder of sympathy. The 

 dog aboard ship would thereupon mark the exact time with a 

 yelp and so solve the marine clock problem! 



John Harrison, without a dog, eventually produced in 1736 

 the first marine chronometer. It was far from pretty and 

 weighed seventy-two pounds, but it did keep good time at sea. 

 After more than thirty years his fifth clock justified his long 

 labors, for it had the surprisingly small error of less than five 

 seconds in ten weeks. Bureaucracy was the same then as it is 

 now — the prize was awarded to him only after considerable 

 haggling on the part of the Board of Longitude. 



The development of chronometers and of more accurate 

 instruments for measuring altitude, like the modern sextant, 



