The Cruise of the Snark Page 20
Again alas and alack! The Correct Magnetic Course was not the Compass Course. There was another sly little devil lying in wait to trip me up and land me smashing on the reefs of Vatu Leile. This little devil went by the name of Deviation. I read:
“The Compass Course is the course to steer, and is derived from the Correct Magnetic Course by applying to it the Deviation.”
Now Deviation is the variation in the needle caused by the distribution of iron on board ship. This purely local variation I derived from the deviation card of my standard compass and then applied to the Correct Magnetic Course. The result was the Compass Course. And yet, not yet. My standard compass was amidships on the companionway. My steering compass was aft, in the cockpit, near the wheel. When the steering compass pointed west-by-south-three-quarters-south (the steering course), the standard compass pointed west-one-half-north, which was certainly not the steering course. I kept the Snark up till she was heading west-by-south-three-quarters-south on the standard compass, which gave, on the steering compass, southwest-by-west.
The foregoing operations constitute the simple little matter of setting a course. And the worst of it is that one must perform every step correctly or else he will hear “Breakers ahead!” some pleasant night, receive a nice sea-bath, and be given the delightful diversion of fighting his way to the shore through a horde of man-eating sharks.
Just as the compass is tricky and strives to fool the mariner by pointing in all directions except north, so does that guide-post of the sky, the sun, persist in not being where it ought to be at a given time. This carelessness of the sun is the cause of more trouble—at least it caused trouble for me. To find out where one is on the earth’s surface, he must know, at precisely the same time, where the sun is in the heavens. That is to say, the sun, which is the time-keeper for men, doesn’t run on time. When I discovered this, I fell into deep gloom and all the Cosmos was filled with doubt. Immutable laws, such as gravitation and the conservation of energy, became wobbly, and I was prepared to witness their violation at any moment and to remain unastonished. For see, if the compass lied and the sun did not keep its engagements, why should not objects lose their mutual attraction and why should not a few bushel baskets of force be annihilated? Even perpetual motion became possible, and I was in a frame of mind prone to purchase Keeley-Motor stock from the first enterprising agent that landed on the Snark’s deck. And when I discovered that the earth really rotated on its axis 366 times a year, while there were only 365 sunrises and sunsets, I was ready to doubt my own identity.
This is the way of the sun. It is so irregular that it is impossible for man to devise a clock that will keep the sun’s time. The sun accelerates and retards as no clock could be made to accelerate and retard. The sun is sometimes ahead of its schedule; at other times it is lagging behind; and at still other times it is breaking the speed limit in order to overtake itself, or, rather, to catch up with where it ought to be in the sky. In this last case it does not slow down quick enough, and, as a result, goes dashing ahead of where it ought to be. In fact, only four days in a year do the sun and the place where the sun ought to be happen to coincide. The remaining 361 days the sun is pothering around all over the shop. Man, being more perfect than the sun, makes a clock that keeps regular time. Also, he calculates how far the sun is ahead of its schedule or behind. The difference between the sun’s position and the position where the sun ought to be if it were a decent, self-respecting sun, man calls the Equation of Time. Thus, the navigator endeavoring to find his ship’s position on the sea, looks in his chronometer to see where precisely the sun ought to be according to the Greenwich custodian of the sun. Then to that location he applies the Equation of Time and finds out where the sun ought to be and isn’t. This latter location, along with several other locations, enable him to find out what the man from Kansas demanded to know some years ago.
The Snark sailed from Fiji on Saturday, June 6, and the next day, Sunday, on the wide ocean, out of sight of land, I proceeded to endeavor to find out my position by a chronometer sight for longitude and by a meridian observation for latitude. The chronometer sight was taken in the morning, when the sun was some 21° above the horizon. I looked in the Nautical Almanac and found that on that very day, June 7, the sun was behind time 1 minute and 26 seconds, and that it was catching up at a rate of 14.67 seconds per hour. The chronometer said that at the precise moment of taking the sun’s altitude it was twenty-five minutes after eight o’clock at Greenwich. From this date it would seem a schoolboy’s task to correct the Equation of Time. Unfortunately, I was not a schoolboy. Obviously, at the middle of the day, at Greenwich, the sun was 1 minute and 26 seconds behind time. Equally obviously, if it were eleven o’clock in the morning, the sun would be 1 minute and 26 seconds behind time plus 14.67 seconds. If it were ten o’clock in the morning, twice 14.67 seconds would have to be added. And if it were 8:25 in the morning, then 3½ times 14.67 seconds would have to be added. Quite clearly, then, if, instead of being 8:25 A.M., it were 8:25 P.M., then 8½ times 14.67 seconds would have to be, not added, but subtracted; for, if, at noon, the sun were 1 minute and 26 seconds behind time, and if it were catching up with where it ought to be at the rate of 14.67 seconds per hour, then at 8:25 P.M. it would be much nearer where it ought to be than it had been at noon.
So far, so good. But was that 8:25 of the chronometer A.M. or P.M.? I looked at the Snark’s clock. It marked 8:9, and it was certainly A.M., for I had just finished breakfast. Therefore, if it was eight in the morning on board the Snark, the eight o’clock of the chronometer (which was the time of the day at Greenwich) must be a different eight o’clock from the Snark’s eight o’clock. But what eight o’clock was it? It can’t be the eight o’clock of this morning, I reasoned; therefore, it must be either eight o’clock this evening or eight o’clock last night.
It was at this juncture that I fell into the bottomless pit of intellectual chaos. We are in east longitude, I reasoned, therefore we are ahead of Greenwich. If we are behind Greenwich, then to-day is yesterday; if we are ahead of Greenwich, then yesterday is to-day, but if yesterday is to-day, what under the sun is to-day!—to-morrow? Absurd! Yet it must be correct. When I took the sun this morning at 8:25, the sun’s custodians at Greenwich were just arising from dinner last night.
“Then correct the Equation of Time for yesterday,” says my logical mind.
“But to-day is to-day,” my literal mind insists. “I must correct the sun for to-day and not for yesterday.”
“Yet to-day is yesterday,” urges my logical mind.
“That’s all very well,” my literal mind continues. “If I were in Greenwich I might be in yesterday. Strange things happen in Greenwich. But I know as sure as I am living that I am here, now, in to-day, June 7, and that I took the sun here, now, to-day, June 7. Therefore I must correct the sun here, now, to-day, June 7.”
“Bosh!” snaps my logical mind. “Lecky says—”
“Never mind what Lecky says,” interrupts my literal mind. “Let me tell you what the Nautical Almanac says. The Nautical Almanac says that to-day, June 7, the sun was 1 minute and 26 seconds behind time and catching up at the rate of 14.67 seconds per hour. It says that yesterday, June 6, the sun was 1 minute and 36 seconds behind time and catching up at the rate of 15.66 seconds per hour. You see, it is preposterous to think of correcting to-day’s sun by yesterday’s time-table.”
“Fool!”
“Idiot!”
Back and forth they wrangle until my head is whirling around and I am ready to believe that I am in the day after the last week before next.
I remembered a parting caution of the Suva harbormaster: “In east longitude take from the Nautical Almanac the elements for the preceding day.”
Then a new thought came to me. I corrected the Equation of Time for Sunday and for Saturday, making two separate operations of it, and lo, when the results were compared, there was a difference only of four-tenths of a second. I was a changed man. I had found my
way out of the crypt. The Snark was scarcely big enough to hold me and my experience. Four-tenths of a second would make a difference of only one-tenth of a mile—a cable-length!
All went merrily for ten minutes, when I chanced upon the following rhyme for navigators:
“Greenwich time least
Longitude east;
Greenwich best,
Longitude west.”
Heavens! The Snark’s time was not as good as Greenwich time. When it was 8:25 at Greenwich, on board the Snark it was only 8:9. “Greenwich time best, longitude west.” There I was. In west longitude beyond a doubt.
“Silly!” cries my literal mind. “You are 8:9 A.M. and Greenwich is 8:25 P.M.”
“Very well,” answers my logical mind. “To be correct, 8:25 P.M. is really twenty hours and twenty-five minutes, and that is certainly better than eight hours and nine minutes. No, there is no discussion; you are in west longitude.”
Then my literal mind triumphs.
“We sailed from Suva, in the Fijis, didn’t we?” it demands, and logical mind agrees. “And Suva is in east longitude?” Again logical mind agrees. “And we sailed west (which would take us deeper into east longitude), didn’t we? Therefore, and you can’t escape it, we are in east longitude.”
“Greenwich time best, longitude west,” chants my logical mind; “and you must grant that twenty hours and twenty-five minutes is better than eight hours and nine minutes.”
“All right,” I break in upon the squabble; “we’ll work up the sight and then we’ll see.”
And work it up I did, only to find that my longitude was 184° west.
“I told you so,” snorts my logical mind.
I am dumbfounded. So is my literal mind, for several minutes. Then it enounces:
“But there is no 184° west longitude, nor east longitude, nor any other longitude. The largest meridian is 180° as you ought to know very well.”
Having got this far, literal mind collapses from the brain strain, logical mind is dumb flabbergasted; and as for me, I get a bleak and wintry look in my eyes and go around wondering whether I am sailing toward the China coast or the Gulf of Darien.
Then a thin small voice, which I do not recognize, coming from nowhere in particular in my consciousness, says:
“The total number of degrees is 360. Subtract the 184° west longitude from 360°, and you will get 176° east longitude.”
“That is sheer speculation,” objects literal mind; and logical mind remonstrates. “There is no rule for it.”
“Darn the rules!” I exclaim. “Ain’t I here?
“The thing is self-evident,” I continue. “184° west longitude means a lapping over in east longitude of four degrees. Besides I have been in east longitude all the time. I sailed from Fiji, and Fiji is in east longitude. Now I shall chart my position and prove it by dead reckoning.”
But other troubles and doubts awaited me. Here is a sample of one. In south latitude, when the sun is in northern declination, chronometer sights may be taken early in the morning. I took mine at eight o’clock. Now, one of the necessary elements in working up such a sight is latitude. But one gets latitude at twelve o’clock, noon, by a meridian observation. It is clear that in order to work up my eight o’clock chronometer sight I must have my eight o’clock latitude. Of course, if the Snark were sailing due west at six knots per hour, for the intervening four hours her latitude would not change. But if she were sailing due south, her latitude would change to the tune of twenty-four miles. In which case a simple addition or subtraction would convert the twelve o’clock latitude into eight o’clock latitude. But suppose the Snark were sailing southwest. Then the traverse tables must be consulted.
This is the illustration. At eight A.M. I took my chronometer sight. At the same moment the distance recorded on the log was noted. At twelve M., when the sight for latitude was taken, I again noted the log, which showed me that since eight o’clock the Snark had run 24 miles. Her true course had been west ¾ south. I entered Table 1, in the distance column, on the page for ¾ point courses, and stopped at 24, the number of miles run. Opposite, in the next two columns, I found that the Snark had made 3.5 miles of southing or latitude, and that she had made 23.7 miles of westing. To find my eight o’clock latitude was easy. I had but to subtract 3.5 miles from my noon latitude. All the elements being present, I worked up my longitude.
But this was my eight o’clock longitude. Since then, and up till noon, I had made 23.7 miles of westing. What was my noon longitude? I followed the rule, turning to Traverse Table No. 11. Entering the table, according to rule, and going through every detail, according to rule, I found the difference of longitude for the four hours to be 25 miles. I was aghast. I entered the table again, according to rule; I entered the table half a dozen times, according to rule, and every time found that my difference of longitude was 25 miles. I leave it to you, gentle reader. Suppose you had sailed 24 miles and that you had covered 3.5 miles of latitude, then how could you have covered 25 miles of longitude? Even if you had sailed due west 24 miles, and not changed your latitude, how could you have changed your longitude 25 miles? In the name of human reason, how could you cover one mile more of longitude than the total number of miles you had sailed?
It was a reputable traverse table, being none other than Bowditch’s. The rule was simple (as navigators’ rules go); I had made no error. I spent an hour over it, and at the end still faced the glaring impossibility of having sailed 24 miles, in the course of which I changed my latitude 3.5 miles and my longitude 25 miles. The worst of it was that there was nobody to help me out. Neither Charmian nor Martin knew as much as I knew about navigation. And all the time the Snark was rushing madly along toward Tanna, in the New Hebrides. Something had to be done.
How it came to me I know not—call it an inspiration if you will; but the thought arose in me: if southing is latitude, why isn’t westing longitude? Why should I have to change westing into longitude? And then the whole beautiful situation dawned upon me. The meridians of longitude are 60 miles (nautical) apart at the equator. At the poles they run together. Thus, if I should travel up the 180° meridian of longitude until I reached the North Pole, and if the astonomer at Greenwich travelled up the 0° meridian of longitude to the North Pole, then, at the North Pole, we could shake hands with each other, though before we started for the North Pole we had been some thousands of miles apart. Again: if a degree of longitude was 60 miles wide at the equator, and if the same degree, at the point of the Pole, had no width, then somewhere between the Pole and the equator that degree would be half a mile wide, and at other places a mile wide, two miles wide, ten miles wide, thirty miles wide, ay, and sixty miles wide.
All was plain again. The Snark was in 19° south latitude. The world wasn’t as big around there as at the equator. Therefore, every mile of westing at 19° south was more than a minute of longitude; for sixty miles were sixty miles, but sixty minutes are sixty miles only at the equator. George Francis Train broke Jules Verne’s record of around the world. But any man that wants can break George Francis Train’s record. Such a man would need only to go, in a fast steamer, to the latitude of Cape Horn, and sail due east all the way around. The world is very small in that latitude, and there is no land in the way to turn him out of his course. If his steamer maintained sixteen knots, he would circumnavigate the globe in just about forty days.
But there are compensations. On Wednesday evening, June 10, I brought up my noon position by dead reckoning to eight P.M. Then I projected the Snark’s course and saw that she would strike Futuna, one of the easternmost of the New Hebrides, a volcanic cone two thousand feet high that rose out of the deep ocean. I altered the course so that the Snark would pass ten miles to the northward. Then I spoke to Wada, the cook, who had the wheel every morning from four to six.
“Wada San, to-morrow morning, your watch, you look sharp on weather-bow you see land.”
And then I went to bed. The die was cast. I had staked my reputation as a
navigator. Suppose, just suppose, that at daybreak there was no land. Then, where would my navigation be? And where would we be? And how would we ever find ourselves? or find any land? I caught ghastly visions of the Snark sailing for months through ocean solitudes and seeking vainly for land while we consumed our provisions and sat down with haggard faces to stare cannibalism in the face.
I confess my sleep was not
“. . . like a summer sky
That held the music of a lark.”
Rather did “I waken to the voiceless dark,” and listen to the creaking of the bulkheads and the rippling of the sea alongside as the Snark logged steadily her six knots an hour. I went over my calculations again and again, striving to find some mistake, until my brain was in such fever that it discovered dozens of mistakes. Suppose, instead of being sixty miles off Futuna, that my navigation was all wrong and that I was only six miles off? In which case my course would be wrong, too, and for all I knew the Snark might be running straight at Futuna. For all I knew the Snark might strike Futuna the next moment. I almost sprang from the bunk at that thought; and though I restrained myself, I know that I lay for a moment, nervous and tense, waiting for the shock.
My sleep was broken by miserable nightmares. Earthquake seemed the favorite affliction, though there was one man, with a bill, who persisted in dunning me throughout the night. Also, he wanted to fight; and Charmian continually persuaded me to let him alone. Finally, however, the man with the everlasting dun ventured into a dream from which Charmian was absent. It was my opportunity, and we went at it, gloriously, all over the sidewalk and street, until he cried enough. Then I said, “Now how about that bill?” Having conquered, I was willing to pay. But the man looked at me and groaned. “It was all a mistake,” he said; “the bill is for the house next door.”