"Then," hazarded Christopher after a moment's thought, "there really is exact time and common time."
"Broadly speaking, yes," acquiesced McPhearson. "Or in other words there is time scientifically measured and time that is measured by man-made laws. The difference, as I told you, is of more importance to astronomers and mariners than to anybody else; and yet the puzzle for many centuries balked those who sought to establish a perfect system of time-keeping. As better ships were built and adventurous persons began to sail the ocean both for trade and conquest, captains soon discovered the stars and the compass could not be relied upon to furnish them the reliable information they needed in locating their position. Therefore, about 1713 England offered a prize of £20,000 to any one who should invent a timekeeper sufficiently accurate to enable navigators to ascertain from it longitude at sea."
The Scotchman paused to take from his table a box of tiny brass screws from which he selected one that was to his liking.
"Now there was living at this period John Harrison, a Yorkshire clockmaker, who although quite a young man had made a clock with wooden works into which he had put a gridiron pendulum—a device he had thought out to overcome the difficulties resulting from atmospheric conditions. This clock was so skillfully adjusted that it did not vary a second a month. So you can see that despite the fact Harrison was not a member of the Clockmakers' Company he was certainly qualified to be."
"And did he go after the prize money?"
"Apparently the offer tempted him. Perhaps he not only desired to win the fortune offered but also wished the fun of solving the riddle the government propounded. At any rate, in 1728 he came to London prepared to present drawings of an instrument he felt certain would turn the trick and had not his friends deterred him he would have placed these sketches before the commission. Fortunately, however, he had excellent advisers (among whom was honest John Graham) and they assured him he would stand a far better chance of securing a favorable hearing should he first construct the instrument of which he at present had nothing but pictures. Now such counsel as this was pretty disheartening to a young man who, fired with hope and ambition, had come all the way to London confidently expecting to have his plan hailed with joy when he arrived. Nevertheless Harrison was open-minded enough to accept his friends' guidance and acting upon it he went home again and worked for seven years on the instrument he had drawn out on paper."
"And then did he bring it to London?" was Christopher's breathless demand.
"Yes," affirmed McPhearson. "The contrivance, however, was by no means perfect. Still it showed sufficient promise to interest the commissioners and lead them to give Harrison permission to go to Lisbon on one of the king's ships; that he might correct his reckonings by taking practical observations at sea. Moreover they also paid him £5,000 of the prize money to encourage him. This financial spur, together with the faith it represented, stimulated the patient instrument-maker to fashion a second timekeeper on which he spent four years of hard work. But even this one, although better than the first, failed to meet the demands, and he tried again, taking ten years to perfect a third. This was smaller and as it seemed to foreshadow good results he was awarded the gold medal annually presented by the Royal Society for the most useful nautical discovery thus far made. Yet notwithstanding this triumph the article he had produced did not suit him. Experience had, in the meantime, taught him a great deal, and after more corrections and improvements he came again before the committee and asked that the device he now had might be given practical trial."
Christopher hitched his stool a little nearer.
"Now governments, like elephants and mastodons, move slowly, and by the time the coveted permission was granted poor Harrison was well-nigh seventy years old and instead of setting out on an ocean voyage for Jamaica he was forced to surrender his place to his son, William, whom he had trained up as one of his apprentices."