Evening Republican, Volume 21, Number 40, Rensselaer, Jasper County, 25 February 1918 — NEED SEXTANTS FOR NAVIGATORS [ARTICLE]

NEED SEXTANTS FOR NAVIGATORS

United States Swept Bare of Instruments Used to Guide Ships. OLD CAPTAINS TO RESCUE Out of Closets and Attics Are Dug Sextants That Have Not Been Used for Years—Navigators’ Aid Columbus Did Not Have. Washington.—One of the early effects of the war was an acute shortage of the instrument most used in navigating ships at sea, the sextant In a few weeks after the United States became a party to the great struggle, the market was swept bare of what might be termed the floating supply of these important instruments. Since then, importations from England, Canada and France have eased the American market somewhat, but there is still a sufficient shortage to hold the price far above what it formerly was. In. the early months of this country’s participation in the war, when the United States shipping board was establishing the chain of navigation schools at which it is training officers for the new merchant marine, there was such a scarcity of these necessary instruments —which are used daily in the schools to teach methods of determining a ship's position at sea—that an appeal was made for the loan of instruments. The result was striking. Out of the closets and attics of former captain's homes, particularly in New England, sextants appeared that had not seen the light, in some cases, since the days of the clipper-ship era, when the United States was supreme on the sea. Many of these instruments had been on long voyages to the mysterious East; others had been In the whale fishery to the far North; a few had been carried among the Cannibal Islands of the South Pacific, others among the pirates of the China seas. It had not been thought, when these instruments were stowed away by careful hands, years ago, that they would ever again serve the merchant marine. Today many of them are being used by young men who will qualify as officers on the new and greater merchant marine, while others, which have been presented to the shipping board, are actually making voyages again, this time among the pirates of the submarine zone.

A sextant, unlike, a watch or any instrument with constantly moving parts, is very slow to wear out. There is not much difference in the sextant of today and the original sextants produced in England when the instrument was first perfected by John Hadley, back in 1731. First Was an Octant. Hadley called his instrument at first an octant, because it represented in its scale of degrees but an eighth part of the circle, that is, 45 degrees. Later Instruments were termed quadrants, as they represented a quarter of a circle, 90 degrees. The sextant, or sixth of a circle, 60 degrees, was found to be most practical, and in time came into general use. The practical distinction between these three instruments is slight, however. The first sextant was not an invention, as might be supposed, but an adaptation of ancient instruments used by astronomers from time immemorial to determine the sun’s elevation, or latitude. The oldest of these ancient instruments w;as the astrolabe, a disk of copper or brass, cut to the full circle of 360 degrees. This was fitted with a plumb line, and on its face a bar pivoted on the center, and having at one end a pin. One man held up the disk by the line, another sighted the sun over the pin in the end of the bar, and another noted where the shadow cast by the pin fell on the scale of degrees marked on the disk.

It thus took three men to make an observation, which was usually faulty, while the use of such an instrument on a moving ship was almost an impossibility. Another ancient observing Instrument was the cross-staff. This consist- \ ed of a bar of wood —some of them were seven feet long—fitted with a sliding upright bar, or cross. The long bar was held toward the sun, and the observer was posted at one end. The shorter bar wasjfcen moved back or forth until the observer saw the sun over its upper tip and the horizon at the same time under Its lower lip. The angle thus determined was marked on a scale on the long bar. A grave objection to this Instrument was that the observer was obliged to look at the sun and the horizon at the same time. Columbus used both Instruments on his voyage to the new world, bujxftpparently neither helped him mtfch in determining the position of hft ships, which he could only guess At until he made a landfall in the WesUlndies. Hadley Invents Instrument John Hadley conceived the idea of employing the principle of tfie crossistiiff in an instrument that wbuld en- ’ able the observer to see b\th the sun and the horizon when looking at the latter. This he accomplished by arranging a series of mirrors in such a way that the observer by the movement of an arm, or lever, attached to

an arc brought the sun down to touch the horizon. When the observer using the sextant gets the sun down to the horizon, he fixes the arm on the scale by means of a screw, and proceeds to read the scale, which gives him the sun’s altitude in degrees. When Hadley brought his sextant out in 1731, it was given a trial by the British authorities, on the yacht Chatham, off Spithead, on a gusty day in August. We read that the weather “was too rough for unsatisfactory test” Rough weather Is a frequent cause for trouble in handling the sextant as it is difficult to “catch” the sun and bring it down when on

the uncertain platform of a moving deck. The value of Hadley’s instrument was jnot at once recognized by mariners, but its worth has been amply demonstrated by the fact that no essential change'has been made in it since it first appeared, nearly two centuries ago. With the sextant perfected, the apparatus used by a navigator was greatly reduced in bulk. Some of the ancieht ships, bound on long voyages, took along a great variety of appliances that today would be valuable only as junk or curios. Now the American officer, ready tu ship for service overseas, takes his sextant, the most important of all nav. igating instruments next to the compass, in a neat mahogany case only nine inches square by five Inches deep, and needs nothing further, except the ship’s chronometer, to enable him to tell where he is every day on his voyage across the vasty deep.