Sharks not unfrequently follow a vessel in moderate weather for several days, and in tropical latitudes sometimes lurk under a ship's bottom, watching a chance to gratify their appetites. For this reason it is dangerous for a person to bathe in the sea during a calm, as they are by no means choice in regard to their food, but will as readily make a meal from the leg of a sailor as from the wing of a chicken.
Mr. Thompson related a case which occurred on board a vessel belonging to Portsmouth, the year before, and to which he was a witness. One Sunday morning, in the warm latitudes, while the sea was calm, a young man, on his first voyage, quietly undressed himself, and without a word to any one, thoughtlessly mounted the cathead and plunged into the water. He swam off some distance from the ship, and laughing and shouting, seemed greatly to admire the refreshing exercise. The captain, on being informed of his imprudent conduct, called to him, rebuked him severely, and ordered him to return immediately to the ship. The young sailor turned about, wondering what impropriety there could be in taking a pleasant bath during such sultry weather. He swam beneath the fore-chain-wales, and took hold of a rope to aid him in getting on board. A couple of his shipmates also seized him by the wrists to assist him in climbing up the side. For a moment he remained motionless, with half his body in the water, when a huge shark, that had been lying in wait under the ship's bottom, seized him by the leg. The unfortunate young man uttered the most piteous screams, and every one was instinctively aware of the cause of his terrible agony. The captain ordered the men who held the arms of the sufferer to "hold on," and jumped in the chain-wale himself to assist them. By main strength the poor fellow was dragged fainting on board; but his foot was torn off, together with a portion of the integuments of the leg, and the bones were dreadfully crushed. He lived in agony a few days, when he expired. Incidents of this nature will satisfactorily account for the hatred which a sailor bears towards a shark.
Chapter IV. LAND, HO!
On the day succeeding the capture of the shark a fine breeze sprung up. Once more the white foam appeared beneath the bows, as the old brig plunged, and rolled, and wriggled along on her way towards Demarara. With a strong breeze on the quarter, it required not only labor, but skill, to steer the interesting craft. One of the "old salts," having been rebuked by the captain for steering wildly, declared, in a grave but respectful tone, that he could steer as good a trick at the helm as any man who ever handled a marlinspike; but he "verily believed the old critter knew as much as a Christian, and was obstinately determined to turn round and take a look at her starn!"
The regular "trade wind" now commenced, and there was a prospect, although still a distant one, of ultimately reaching the port to which we were bound. The trade winds blow almost constantly from one direction, and prevail in most parts of the Atlantic and Pacific Oceans, between the latitudes of twenty-eight degrees north and twenty-eight degrees south. In northern latitudes the trade wind blows from north-east, or varies but a few points from that direction. South of the equator it blows constantly from the south-east; and the "south-east trade" is more steady than the trade wind north of the line.
It often happens that vessels bound to the United States from India, after passing the Cape of Good Hope, steer a course nearly north-west, carrying studding-sails on both sides, uninterruptedly, through fifteen or twenty degrees of latitude.
The cause of the trade winds is supposed to be the joint influence of the higher temperature of the torrid zone and the rotation of the earth on its axis. On the equator, and extending sometimes a few degrees on either side, is a tract where light easterly winds, calms, and squalls, with thunder, lightning, and inundating rains, prevail.
From what I have said, it will be seen that vessels bound from the American coast to the West Indies or Guiana should steer to the eastward in the early part of their passage, while they have the advantage of variable winds. And this precaution is the more important, as these vessels, being generally dull sailers and deeply laden, will fail to reach their port if they fall to leeward, unless by returning north into the latitude of the variable winds, and making another trial, with the benefit of more experience.
In those days there were no chronometers in use, and but few of our West India captains were in possession of a sextant, or indeed able to work a lunar observation. The latitude was accurately determined every day by measuring the altitude of the sun as it passed the meridian. To ascertain the longitude was a more difficult matter. They were obliged to rely mainly on their dead reckoning; that is, to make a calculation of the course and distance run daily, from the points steered by the compass and the rate as indicated by the log-line and half-glass. A reckoning on such a basis, where unknown currents prevail, where a vessel is steered wildly, or where the rate of sailing may be inaccurately recorded, is liable to many errors; therefore it was customary with all prudent masters, in those days, especially if they distrusted their own skill or judgment in keeping a reckoning to KEEP WELL TO THE EASTWARD. This was a general rule, and looked upon as the key to West India navigation. Sometimes a vessel bound to the Windward Islands, after reaching the latitude of her destined port, found it necessary to "run down," steering due west, a week or ten days before making the land.