This watch was a very good timekeeper, being by one of the best London makers; and, hitherto, had maintained an irreproachable character in this respect, the cook at home, whenever the kitchen clock went wrong, always appealing to me to know what was the correct time, with the flattering compliment that “Master Allan’s watch, at all events,” was “sure to be right!”
But now, strange to say, although my watch kept exactly to railway time up to the day of my arrival in London and while we were on our way down the river, I found that, as we proceeded into the Channel and out to sea it began to gain, the difference being more and more marked as we got further to the westward; until, when the captain, after taking the sun on our fifth day out, told Tom Jerrold who was on the deck beside him to “make it eight bells,” or strike the ship’s bell to declare it was noon, I was very nearly an hour ahead of that time—my watch, which I was always careful about winding up every evening as father enjoined me when giving it to me, pointing actually to one o’clock!
I could not understand it all.
Mr Mackay, however, made it clear to me after a little explanation, showing me, too, how simple a matter it was with a good chronometer to find a ship’s position at sea.
“For every degree of longitude we go westwards from the meridian of Greenwich, which is marked with a great round 0 here, you see, my boy, we gain four minutes,” said he, pointing out the lines of longitude ruled straight up and down the chart as he spoke, for my information; “and thus, the fact of the hands of your watch telling, truly enough, that it is now about eight minutes to one o’clock in London, shows that we are thirteen degrees further to the west than at the place where your time is set—for we are going with the sun, do you see?”
“Yes, I see, sir,” said I; “but suppose we were going to the east instead of the west?”
“Why then, my boy,” he replied, “your watch, in lieu of gaining, would appear to lose the same number of minutes each day, according to our rate of sailing. A ship, consequently, which goes round the world from the east to the west will seem to have gained a clear day on circumnavigating the globe; while one that completes the same voyage sailing from the west continually towards the east, loses one.”
“How funny!” cried I. “Is it really so?”
“Yes, really,” said he; “and I’ve seen, on board a ship I was once in, the captain skip a day in the log, to make up for the one we lost on the voyage, passing over Saturday and writing down the day which followed Friday as ‘Sunday’—otherwise we would have been all out of our reckoning with the almanac.”
“How funny!” I repeated. “I never heard that before.”