For generations, then, the mariner was left to depend upon his dead-reckoning, which, as one method of navigating a ship, is still in force, and I do not know that we have in any way altered this old practice of computing, save by the introduction of the patent log, whose indications are still in some directions checked by the log-reel of our forefathers. Dead-reckoning simply consists of ascertaining how fast the ship sails by heaving the log, by entering the courses sailed, by allowing for leeway. The ship, let us say, steered north-east for one hour, north-east by north during the following hour, north-north-east for the third hour, and then during the fourth hour came up to north-east again. In those four hours her rate varied: at one o’clock the log showed her sailing at seven knots; at two, five-and-a-half knots; at three, four-and-three-quarter knots; at four, six knots; and her leeway was sometimes three-quarters of a point, sometimes one point, sometimes more. Her place, then, on the chart may be easily set down or “pricked” out of these entries in the log-slate. In thick weather there is no other way of computing a ship’s progress and position. The sky may be obscured for days, and all that a man can do is to heave his log, watch how the ship heads, and observe her leeway. It was in this fashion that the ancient mariner contrived to crawl about the ocean, and it is worth observing that the log he measured his way with we still possess and use. No ship, I should think, goes to sea without the reel, the line, and the glass. The rotating logs tell you how far you have gone in a given time with tolerable accuracy; but the reel-log is the only appliance that I am acquainted with which will tell you how fast you are going at the moment.
Seamen have told me that with their eye they can tell the speed of their ship more accurately than with the log-line. I do not believe this, and on testing these cocksure men I have never once found them right within half a knot. Of course this refers to sailing ships. A steamer goes along steadily, and it is quite conceivable that a person accustomed to steamships could tell correctly the speed of one by looking over the side. But a sailing vessel varies her rate with every puff. Under certain conditions the increased sail that seems to be thrashing her through it with greater velocity has diminished her speed. I particularly recollect an instance. A dynamometer was attached to the taffrail of a large full-rigged ship; to it was affixed a line which it dragged through the water. The pull of the line was equivalent to a weight of sixty pounds. The vessel was then sailing with the wind a point before the beam, under all plain sail, the breeze fresh. The foretopmast studding-sail was set, and the hand of the dynamometer went back, showing that the speed had been decreased to the extent illustrated by this diminution of weight in the pull of the line by the setting of the studding-sail. The chief officer, however, was so certain that the ship had improved her speed, despite the unmistakable indications of the dynamometer, that to prove his judgment he ordered the log to be hove, with the result that the speed was less by a knot (I think) than it had been before the studding-sail was set. The fact is, the ship had sail enough; the additional canvas simply buried, and so retarded her. Yet this same mate was one of many seamen who had assured me that they could tell the speed of a vessel better with the eye than with the log.
It is true, nevertheless, that the mariners of certain nations in former times chose the eye in preference to the knotted line. The Dutch, in particular, though they always took the reel and glass to sea with them, seldom used them. There looks to have been something of laziness in their habit. An account of the Hollander’s slatternly trick of navigation may be found in a note to “Voyages to the East Indies by the late John Splinter Stavorinus,” in 1768–71–74 and ’75. This author tells us that the Dutchmen of his own and of earlier times steered by the true compass, or rather endeavoured to do so, “by means of a small central movable card, which they set to the meridian; and whenever they discover the variation has altered twenty-two degrees since the last adjustment, they again correct the central card. This is steering within a quarter of a point without aiming at greater exactness.” There was the same guesswork in their dead-reckoning. They hove no log, says Stavorinus. The officer of the watch corrected the course for leeway by his own judgment before marking it down on the logboard. They computed their speed by measuring a distance of forty feet along the ship’s side. “They take notice of any remarkable patch of froth when it is abreast of the foremost end of the measured distance, and count half-seconds till the mark of froth is abreast of the after end. With the number of half-seconds thus obtained they divide the number forty-eight, taking the product for the rate of sailing in geographical miles in one hour, or the number of Dutch miles in four hours.” One finds the same phlegmatic indifference in their manner of taking sights. “It is not usual to make any allowance in the sun’s declination on account of being on a different meridian from that for which the tables are calculated. They in general compute the numbers just as they are found in the tables. From all this,” drily adds Stavorinus, “it is not difficult to conceive the reason why the Dutch are frequently above ten degrees out in their reckoning.”
The Spaniards and the Portuguese were more wary, if not more knowing, than the Dutch. Extreme vigilance in conning ship was apparently a feature of the navigation of those old and famous races of mariners. Sir Richard Hawkins (Purchas, vol. iv.) is express in this. I will let him deliver himself in his own quaint inimitable tongue. “In this point of steeridge (steering) the Spaniards and Portugalls do exceede all that I have seene, I meane for their care, which is chiefest in navigation. And I wish in this, and in all their workes of discipline and reformation, we should follow their examples, as also those of any other nation. In every shippe of moment, upon the halfe-decke or quarter-decke, they have a chaire or seate, out of which, whilst they navigate, the pilot, or his adjutants (which are the same officers which in our shippes we term the master and his mates) never depart day nor night from the sight of the compasse, and have another before them, whereby they see what they doe, and are ever witnesses of the good or bad steeridge of all men that take the helme.” A later generation of sailors, “Portugalls” as well as others, knew better than to suffer men on the look-out, whether officers of the watch or quarter-masters, to be seated.
The common contrivance for taking the height of the sun at sea in order to obtain the latitude was the cross-staff or fore-staff. It was composed of a wooden staff, upon which was marked a scale of degrees and parts of degrees; it was also fitted with crosspieces for sliding along it at their middle parts. The smallest crosspieces were used for observing the least altitudes. The observation of the sun’s height was taken by means of the shadow which the extremity of the crosspiece cast on the staff when the instrument was adjusted. Contrast this humble, uncouth engine with the sextant of to-day! The back-staff was another implement, the invention of Davis, the Arctic explorer, by the help of which the ancient mariner made his way about the ocean. He had also the astrolabe. Clarke, in his “Progress of Maritime Discovery,” speaks of the sea-astrolabe as deriving its name from the “Armillary sphere invented by Hipparchus at Alexandria.” He finds it first in use among the Portuguese, perhaps because they claim its introduction into Portugal by Martin de Boerina in 1485. The introduction of the cross-staff, on the other hand, is attributed to Warner, who published an account of it at Nuremberg in 1514. As regards the astrolabe, there is certainly a mistake in the date, for we find Chaucer writing a treatise on this instrument in 1391. The method indicated by the old poet for ascertaining the latitude may be accepted as the one employed by the mariners of his own and of much later periods. One special article in his Treatise is entitled by the poet, “Another conclusion to prove the latitude of a region that ye ben in,” and the whole passage is so quaint and interesting withal that every nautical reader of this volume will, I am sure, thank me for transcribing it. I quote from the edition of the Treatise published by Mr. A. E. Brae in 1870.
“If,” writes Chaucer, “thou desire to know this latitude of the region, take the altitude of the sonne in the myddle of the daye, when the sonne is in the hed of Aries or of Libra, for than movethe the sonne in the lyne equinoctial, and abate the nombre of that same sonne’s altitude out of 90 degrees, and than is the remnaunt of the nombre that leveth the altitude of the region; as thus—I suppose that the sonne is thilke daye at noon 38 degrees of heyght; abate, than, 38 degrees out of 90, so leveth ther 52, than is 52 degrees the latitude. I saye not this but for ensample, for wel I wot the latitude of Oxenforde is certain minutes lesse. Nowe, if it so be that thou thinketh too long a tarrying to abyde til that the sonne be in the hed of Aries or Libra, than waite when that the sonne is in any other degree of the zodiake, and consider if the degree of his declinacion be Northward from the equinoctial; abate than from the sonne’s altytude at none the nombre of his declinacion, and than hast thou the height of the hedes of Aries and Libra; as thus—my sonne, peraventure, is in the 10 degree of Leo, almost 56 degrees of height at none, and his declinacion is almost 18 degrees Northward from the equinoctial; abate than thilke 18 degrees of declinacion out of the altitude at none, than leveth 38 degrees—lo there the height of the hed of Aries or Libra and thyn equinoctial in that region.”
So, then, all the ancient mariner had to do was to take the height of the sun, subtract or add the declination, and accept the remainder as his latitude. An easy process, that gives us Cape Horn on the fifty-second parallel and Valdivia on the forty-third![[76]] And yet they managed excellently well, hove their log, turned their hour-glasses, and arrived in due course, their ships covered with barnacles and themselves with glory. In one sense it was the marine age of gold. There were no Board of Trade examinations, no certificates of competency, no obligation to find the time by equal altitudes, or the longitude by chronometer or by lunar observations. The whole art of the navigation of our ancestors is summed up in the account of a voyage sent by Thomas Steevens to his father in 1579, in which he tells him that it is hard to sail from east to west, or contrary, because there is no fixed point in all the sky whereby to direct a course. “I shall tell you,” says he, “what helps God provideth for these men.” And he informs his father that not a “fowle” appears, nor a sign in the air or in the sea which has not been written about by those who make the voyage—that is, to the East Indies. “Wherefore, partly by their own experience, and pondering withal what space the ship was able to make with such a winde, and such direction, and partly by the experience of others whose books and navigations they have, they gesse whereabouts they be.”[[77]]
[76]. That is, according to one or two old maps I have seen.
[77]. I have elsewhere quoted this and other passages. Many of these papers were written at long intervals, and I could not charge my memory with references already made use of.
And accurately enough they “gessed,” too. But then there was no dispatch; every owner of a bottom took his own risks, and a few months sooner or later (chiefly later) was nothing to people who could find a dry dock on every beach, and a market for trucking wherever there was a coloured man. Many generations were born and died before real help came to the mariner, and he was able to sail as securely east or west as north or south. There was no “Nautical Almanac” till the year 1769. This invaluable compilation was originally proposed and then calculated by Dr. Maskelyne, and published by order of the Commissioners of Longitude. So conservative, however, is the character of the seaman that he candidly owned himself but very little obliged to Dr. Maskelyne and the Admiralty. So long afterwards as 1794 I find William Hutchinson, mariner, in a very admirable and voluminous treatise on Naval Architecture, writing in defiant terms touching the “Nautical Almanac.” “The Board of Longitude,” he says, “in order to facilitate the discovery that is expected to be made by this last-mentioned method,” namely, the “Nautical Almanac,” “has ordered that the masters for the Royal Navy must qualify themselves by learning to pass an examination to show that they understand the ‘Nautical Almanac,’ which is a task, in my opinion, that cannot be expected from many of our most hardy and expert navigators, whose education has been mostly from early youth through the hard, laborious, busy scenes of life at sea, and who have never had the opportunity to get the learning that is necessary to understand the true principles of this Almanac.”