Compass
Compass names 3 different subjects across the 6 encyclopedias on this shelf. Each is set out below. 1 of them is described by more than one encyclopedia.
Compass an instrument designed to indicate directions
Described by 2 of the 6 encyclopedias.
Aiton's Encyclopedia (1910)
an instrument designed to indicate directions. It is constructed on the principle that a lodestone, or magnetized needle, will swing into a north and south line if mounted on a pivot, so as to turn freely. A suspended needle and a dial are the essential features. A mariner's compass is swung in rings in such a way that the dial retains a vertical position, however the ship may pitch and toss. These rings are called gimbals. The gimbals with the compass are then placed inside a box, called the binnacle. Inside the binnacle, in the direction of the ship's bow, is a vertical black line called the lubber-line, and the steersman must keep the point of the card which marks the prescribed course always in contact with the black line. The dial is laid off in the figure of a star with thirty-two rays corresponding to the thirty-two directions recognized by a seaman. Between north and northeast, for instance, designated in the usual way by N. and NE., are three additional directions called north-by-east, north-northeast, and north-east-by-north, designated as NbE, NNE, and NEbN respectively. To box the compass is to pass around the dial, beginning at the north, and naming the thirty-two directions consecutively. It is difficult to give proper credit for the invention or discovery of the compass. The Chinese seem to have understood its secret 3,000 years before Europeans learned to steer without the aid of the sun and the North Star . According to some authorities, Marco Polo brought back a knowledge of the compass from Cathay in 1260. Owing to the position of the magnetic poles and the unequal distribution of iron and magnetic ores, there are few lines on the earth's surface where the needle assumes an exact north and south direction. A deviation is called variation of the compass. The compass used for land surveying differs somewhat from the mariner's compass. Engineers who are running railroad lines or surveying public lands ascertain the variation by reference to the North Star and make due allowance. In the United States , the line of no variation crosses Lake Erie into western Pennsylvania and passes southeasterly into the Atlantic, near the boundary between the Carolinas. Dr. William Gilbert, physician to Queen Elizabeth, first explained the action of the compass. In place of the theory that the needle is drawn into position by the influence of certain stars, he showed that the earth is a magnet, and that the earth acts on the needle as one magnet acts on another. Subsequent investigation has demonstrated the truth of Gilbert's theory. Inasmuch as unlike poles of magnets attract each other, that spot in the northern hemisphere that attracts the north pole, or north end of the magnetic needle, is considered the south magnetic pole of the earth. Moreover the magnetic poles are not located at the geographic poles. In 1831 the south magnetic pole was located in Canada in latitude 70 deg. 30', longitude 95 deg. The north magnetic pole, i. e., the pole that attracts the south end of the needle, is in latitude 72 deg 35' S., longitude 152 deg. E. Explorers in polar regions find it necessary to be on guard. When carried to a point east of the south, that is to say, the Canadian magnetic pole, the needle points west, and at a corresponding point to the westward, the needle points east. See North Star ; Roger Bacon; Magnet The variation itself could not be accounted for on the doctrine vulgarly received, that magnetism is an effluvium issuing forth from the root of the tail of the Little Bear, but was scientifically, though erroneously, expressed by Gilbert's hypothesis that earthly substance is attractive--that a needle approaching a continent will incline toward it; and hence that in the midst of the Atlantic, being equally disturbed by Europe and America, it will point evenly between both.--Draper.
Collier's New Encyclopedia (1921)
an instrument used to indicate the magnetic meridian or the position of objects with respect to that meridian, and employed especially on ships, and by surveyors and travelers. Its origin is unknown, but it is supposed to have been brought from China to Europe about the middle of the 13th century. As now generally used it consists of three parts: namely, the box, the card or fly, and the needle the latter being the really essential part, and consisting that it of a small magnet so suspended may be able to move freely in a horizontal direction. The box, ox, which contains the card and needle, is, in the case of the common mariner's compass, a circular brass receptacle hung within a wooden one by two concentric rings called gimbals, so fixed by the cross centers to the box that the inner one, or compass-box, shall retain a horizontal position in all motions of the ship. The circular card is divided into 32 equal parts by lines drawn from the center N NNW Nbyw NW by N 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 85 80 75 70 Wibyn Woys M MSM swby.w M'S SAMS MAS MSS to the circumference, called points or rhumbs; the intervals between the points are also divided into halves and quarters, and the whole circumference into equal parts or degrees, 360 of which complete the circle; and consequently, the distance or angle comprehended between any two rhumbs is equal to 114°. The four principal are called cardinal points: viz., North, South, East and West. The names of the rest are compounded of these. The needle is a small bar of magnetized steel. It is fixed on the under side of the card, and in the center is placed a conical socket, which is poised on an upright pointed pin fixed in the bottom of the box; so that the card, hanging on the pin, turns freely round its center, and one of the points, by the property of the needle, will always be directed toward the North Pole. The needle, however, is liable to a certain deviation owing to the magnetism of the ship itself, and this is especially strong in iron ships. To obviate this defect Sir 65 60 55 50 45 40 35 30 25 20 15 10 505 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 85 80 75 William Thomson invented a compass, having a number of needles arranged in NNE Noy E NE ZN NE SE by E SS 35 ass S COMPASS a particular manner instead of one. In this compass quadrantal errors are corrected by means of two iron globes fixed on opposite sides of the binnacle; while the various components of the ship's magnetic force are neutralized by a series of bar-magnets so arranged as to act as correctors. In the compass used by land-surveyors and others the needle is not fixed to the card, but plays alone, the card being drawn on the bottom of the box.
Compass GYROSCOPE. (See GYRO- SCOPE COMPASS.) CONCRETE SHIPS
Collier's New Encyclopedia (1921)
GYROSCOPE. (See GYRO- SCOPE COMPASS.) CONCRETE SHIPS. The idea of building ships of concrete dates back to the middle of the nineteenth century. In 1849 a small boat of this material was built by a Frenchman named Lambot, and it was still in service in the second decade of the twentieth century. Between 1898 and 1914 a number of larger vessels were built, being used especially as lightbei ers and colliers, but including one schooner which was used for several years in the American coasting trade and which demonstrated the practicalness of concrete construction when on one occasion it was driven on the rocks and came off without suffering any injury. The great impulse to concrete shipbuilding, however, came with the World War when the crying necessity of rapid construction of every kind of vessel led to a somewhat extensive program of concrete building by the U. S. Shipping Board, most of this building consisting of tugs and barges of comparatively small displacement. The first large vessel built of concrete was the "Faith," having a displacement of 8,000 tons. The advantages offered by concrete construction are cheapness and simplicity, with non-combustibility and the virtual elimination of maintenance charges. The most approved construction consists of concrete walls molded on a basket-like skeleton of steel. The necessity of thicker walls than steel alone increases the weight of material in the ship and constitutes the principal disadvantage, reducing the carrying capacity of the vessel while making a larger power plant necessary. CONFERENCE ON LIMITATION OF ARMAMENT. (See WASHINGTON CON- FERENCE.) CO-OPERATIVE MARKETING. The marketing of farm products through associations of farmers is intended to replace the unenlightened, helpless, and unbusiness-like sales methods of individual farmers standing alone with intellicollective merchangent, business-like, dising. Co-operative marketing associations are generally formed by the growers of some special product in some particular State or locality, like the California Prune and Apricot Growers, the Virginia Tobacco Growers' Co-operative Association, and cotton growers' marketing associations in the Carolinas, Mississippi, Oklahoma, and Texas. Co-operative orn crop, while it is estimated that the marketing through farmers' associations is carried on in every section of the United States, although most extensively (before 1921 especially) in California and the North Central States. In 1919 511,383 farms reported sales through associations, this number constituting almost 8 per cent of all the farms in the country. The total amount of sales thus made was $721,983,639, and of this amount almost $600,000,000 was in the Pacific and North Central States, California leading all other States with a total of $127,990,981. The second State in total sales was Minnesota with $82,- 760,459 worth of farm products sold through marketing associations and with 43.9 per cent of all the farms of the State included in such marketing. The most important crops covered in these reports were grain, milk and cream, fruits, and truck crops. During 1921, however, cooperative marketing extended to the South, particularly to the cotton and tobacco States. The Virginia Tobacco Growers' Co-operative Association was organized with a membership of 17,000 growers out of a total of 29,000 in the State, the members agreeing to market for five years solely through the association. Similar organizations were formed among cotton and tobacco growers in North and South Carolina, while the cotton growers of Oklahoma, Texas, and Mississippi have formed associations embracing the majority of growers in these States. In 1921 the California prune and apricot growers renewed their agreement for seven years more, with a membership increased to 90 per cent. Laws against monopolies and combinations have thus far stood in the way of the fullest development of marketing associations, but the Capper-Volstead Cooperative Marketing Act, signed by President Harding, Feb. 18, 1922, removes such obstacles in large degree. COSTA RICA-PANAMA DISPUTE. (See UNITED STATES: FOREIGN AFFAIRS.) COURT OF INTERNATIONAL JUS- TICE. (See PERMANENT COURT OF IN- TERNATIONAL JUSTICE.)
Compass An instrument consisting of a magnetized needle turning freely on a point
American Watchmaker and Jeweler (1892)
An instrument consisting of a magnetized needle turning freely on a point, used to determine horizontal directions in reference to the cardinal points.
What Has Changed in the Last Century
The magnetic needle is now a backup rather than the primary means of finding a course: gyrocompasses, developed by Anschütz-Kaempfe and Sperry in the years just before Collier's wrote in 1921, replaced it on steel warships and liners, and since the GPS constellation was completed in 1995 most ships, aircraft and phones take their heading from satellites. Aiton's 1910 statement that in the United States "the line of no variation crosses Lake Erie into western Pennsylvania" is now badly out of date; that agonic line has migrated hundreds of miles westward, and the north magnetic pole that James Clark Ross fixed in Arctic Canada in 1831 has since raced across the Arctic Ocean, passing near the geographic pole around 2018 and heading toward Siberia at tens of kilometres a year. Gilbert's insight that the earth itself is the magnet still stands, though the field is now attributed to convection in the liquid iron outer core, a model worked out only from the 1940s onward. Aiton's claim that the Chinese knew the secret 3,000 years before Europeans is generous: the earliest clear description of a compass used for navigation is Shen Kuo's, about 1088.
Written for this edition, 2026.