Imagine yourself an ancient mariner. Not in the sense of aged, but in the sense of one sailing the seas 1,000 years ago. Yes, you could sail, but what we call navigation was, at best, dead-reckoning. For some adventurous seamen, "dead" was their fate when their reckoning proved to be bad guessing. Essentially, without knowledge of longitude, guessing is what many a captain did in an effort to know where he was once out of sight of land.
Trying to steer by a star only works when the sky is clear, and the North Atlantic, home seas to Vikings, is notorious for overcast skies and bad weather. Ignorance, weather, and limited navigational skills would seem to combine to make any voyager out's latest venture his last. One can only be amazed at their discoveries of great landmasses far removed from the Baltic and North Seas.
Even Columbus guessed he'd find the Indies if he just headed West, adhering as best he could to a single parallel of latitude. Fortunately, some land stuck out in his way before he ran out of provisions (or into the Indies) and all hands perished at sea. He had to keep faith that land was ho because he had no real idea where he was beyond gauging the length of the day, the height of the sun, or fastening his gaze to known stars. How he returned to the same area on subsequent voyages has more to do with winds, currents, and luck than calculations.
One doesn't have to take one's imagination back 1000 years to still be in perilous seas. For it wasn't until the late middle of the 18th C. that sailors could fix their positions in terms of both latitude and longitude with true accuracy. And we owe that ability to a lone genius, an English clockmaker named John Harrison.
Dava Sobel's book that tells this remarkable story about this most remarkable man is Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of his Time. I was eager to read this account of a genius' life after having read her book, Galileo's Daughter, and enjoying it very much. In it, we learn John Harrison was a humble man.
From the book:
With no formal education or apprenticeship to any watchmaker, Harrison nevertheless constructed a series of virtually friction-free clocks that required no lubrication and no cleaning, that were made from materials impervious to rust, and that kept their moving parts perfectly balanced in relation to one another, regardless of how the world pitched or tossed about them.
To accomplish that, to give the world an accurate, dependable, and easy means to calculate longitude, Harrison labored alone for 40 years. His goal? To solve the world's most difficult problem and to win Britain's Board of Longitude prize of £20,000 (the equivalent of millions of dollars today) to be awarded to the first person who makes a practicable and useful method for determining longitude aboard a ship at sea.
"The Discovery of the Longitude is of such Consequence to Great Britain for the safety of the Navy and Merchant Ships as well as for the improvement of Trade that for want thereof many Ships have been retarded in their voyages, and many lost..." and announced the Longitude Prize "for such person or persons as shall discover the Longitude."
Sobel recounts Harrison's lifelong struggle to invent a chronometer (both practicable and useful) capable of a margin of error within half a degree. Not only the difficulties of invention, absence of technology, and lack of money stood in his way. Also the perfidy of man, the attempts at intellectual theft, even the sabotage of his device presented obstacles to Harrison's success. This is a history of the triumph of one man over Nature, his fellow man, and prevailing culture.
And triumph he did when he made not one but four timepieces that could meet the strict requirements and specifications of the Board. Just the specifications alone were enough to dissuade many serious attempters (though not the un-serious, which we'll talk about in a future diary).
This meant that it could not lose or gain more than three seconds in twenty-four hours. . .Half a degrees of longitude equals two minutes of time, the maximum allowable mistake over the course of a six-week voyage from England to the Caribbean.
Harrison's chronometer would have to pass the stringent test voyage set up by the Board. His first sea clock was a huge device that looked like no other clock seen before or since.
It was monstrous, cumbersome (it's housed in a cabinet four feet in every dimension), and heavy, weighing seventy-five pounds. Hardly a fit thing to make itself welcome in the ultra-tight quarters of a British man-o-war, or merchant ship. He labored on it for seven years, beginning modifications to the design immediately upon completion. However, Harrison did accompany his first sea-going clock aboard the Centurion for a sail to Spithead. The clock proved more sea-worthy than Harrison who spent most of the voyage heaving over the rail.
As soon as he reached home port, Harrison presented himself to the Board and requested that he wished for a different, better clock to make the voyage to the Caribbean. But he'd need two more years to perfect it. His wish was granted and he was given £500 seed money, but was not awarded the prize since he didn't fulfill the required test.
The second timekeeper, H-2, weighed 86 lbs! [No picture] But fit in a smaller box. It survived rigorous agitations and temperature extremes that were worse than would be experienced at sea. Still, Harrison was not satisfied.
Harrison was now 48 years old and would essentially disappear for the next twenty years to work on H-3, emerging only to request an additional stipend of £500 as he "slogged through the difficulties of transforming the bar-shaped balances of the first two timepieces into the circular balance wheels that graced the third." He finished work on it in 1757.
H-4, his masterpiece, was completed in 1759. But back to H-3. When finished, it contained 753 separate parts and contained an innovation found inside today's thermostats, a bi-metallic strip, "which compensates immediately and automatically for changes in temperature that could affect the clock's going rate." Another persistent innovation is Harrison's anti-friction device -- caged ball bearings. H-3 weighed only 60 lbs. and in place of the barbell balances contained two large "circular balances, mounted one above the other, linked by metal ribbons, and controlled by a single spring." It measured two feet high and one foot wide, still was not what Harrison wanted, but was shipshape.
In 1753, the London artisan, John Jeffreys, made Harrison a pocket watch for his personal use, following Harrison's design specifications. It was fitted with a tiny bi-metallic strip and is considered the first true precision watch. Harrison mentioned his watch when he met with the Board in June of 1755, saying he had "good reason to think" on the basis of the watch already executed according to his direction (Jeffreys' watch) "that such small machines may. . .be of great service with respect to the longitude."
In 1759, Harrison finished H-4, the timepiece that won the Longitude Prize. It is 5" in diameter and weighs only three pounds, ticks at five times per second, and ticks to this day on display at the Royal Observatory and National Maritime Museum in Greenwich, London.
Harrison was an old man of 79 when in 1772 he finally received the recognition and prize money he deserved, after King George III intervened on his behalf and after a copy of H-4 sailed with Captain Cook when he embarked on his second voyage of discovery.
The story of how Harrison was denied his prize for so long, how he was sneered at as "a fluke" and how scientist enemies, especially the Royal Astronomer, tried to discredit him in favor of their own pet theories for solving the longitude problem, and how he prevailed over the other major solution to the longitude problem, lunar distance method, will have to wait for next time when I will wrap up the discussion of this book.