Page:The New International Encyclopædia 1st ed. v. 05.djvu/279

COMPASS. ■2:n COMPASS. S., and W.) ; and four are the intereardinal points — northeast, southeast, southwest, ajid northwest (abbreviated N.E., S.E., S.W., and X.W.). The points half way between a cardinal and intereardinal point has a name eompounded of the two, the cardinal point beinj; given first; thus, half way between N, and X.K. is uorth- northeast (N.X.E.i, and half way between east and northeast is east-northeast (E.X.E.). The point on each side of a cardinal or intereardinal point is designated by tirst giving the name of the primary point, then the word hii and the name of the adjacent cardinal point. Thus, the point to the east of north is north by east (N. by E.) ; to the east of northeast is northeast by east (N.E. by E.) ; similarly, ^ve have east by north, south by west, etc. Smaller angles than points are given in half-points, quarter-points, and eigiitli-points. Those arc, in addition to the full points, reckoned from north and from south toward east and west: rcmeral)ering, how- ever, that from the cardinal and intereardinal points for one point each way the fractional parts of a point are reckoned toward the adjacent cardinal point. This gives the points of the compass as follows: COMPASS-CARD. N. N. by E. N. N.E. N.E. by N. N.E. N.E. by E. E. N.E. E. by N. One quadrant in quarter-points is as follows: E. E. by S. E. S.E. S.E. by E. S.E. S.E. by S. S. S.E. S. bv E. S. S. by V. S. S.W. S.W. by S. S.W. S.W. by W. W. S.W. W. by S. W. W. by N. W. N.W. N.W. by W, N.W. N.W. by N. N. N.W. N. bv V. N. N. WE. N. VaE. N. HE. N. by E. N. by E. UE. N. by E. ?4E. N. by E. ?4E. N. N.E. N. N.E. ME. N. N.E. y.E. N. N.E. %E. N.E. by N. N.E. »4.. N.E. M,S. N.E. MN. N.E. N.E. ViE. N.E. VaE. N.E. %E. N.E. by E. N.E. bvE. N.E. bV E. N.E. by E. ME. %E. y.E. E. N.E, E. N.E. UE. E. N.E. VaE. E, N.E. %E. E. by N. E. yiN. E. V4N. E. MX. E. To recite these points, half-points, quarter- points, and eighth-])oiuts in the proper order is called boxinii the coiuikish, and to do so correctly, and to understand the taking of bearings, etc., are among the requirements of a good helmsman or quartermaster (q.v.). For the purpose of taking bearings, an ali- dade or a~imuth circle is used. The former is usually attached to the top of the binnacle- cover, or to some form of duml) compsiss (a metal plate marked with compass points) : it consists of a pivoted bar carrying sights, and by comparing the dumb-comi)ass bearing with the compass heading of the ship, the compass bearing of an object may be olitained. The azi- tnuth circle fits over the top of the compass bowl, and has reflecting mirrors and sighting wires: by their means the l)caring of the sun or other object is ascertained directly from the compass. When the bearing of an object is taken from the north or south ])oint. its angular distance from true north or south is called its azimuth. Thus, if an object bears northeast, its azimuth is N. 4.5° E. The early history of the compass is involved in more or less obscurity. In a rough fomi it was known to the Chinese at least as early as b,c, 2(534, and it was used for the purposes of navigation as early as the third or fourth century a.d., and per- haps before. But the policy of the rulers and the habits and character of the peojjle con- spired to render the Chinese in- different navigators, and the compass did not, therefore, be- come of the great importance to them that it did to the sea- faring nations of Europe. The date of introduction of the magnetic needle into Europe is unknown ; but if it came, as many su])pose, from the Chi- nese through the Arab sailors and traders, it probably was already a nautical instrument. The first reference to it in liter- ature is in a work by Alexan- der Neckani, entitled De Uteii- silibus, and written in the twelfth centuiy. He refers to it as a needle which is placed on a pivot, and when allowed to come to rest shows the mari- ner the direction to steer. In another work, De Naturis Re- rum (lib, ii., c. SO), he writes as follows: "Jlariners at sea. when, through cloudy weather in the day, which hides the sun, or through the darkness of the night, they lose the knowledge of the quar- ter of the world to which they are sailing, touch a needle with a magnet, which will turn round till, on its motion ceasing, its point will be directed toward the north"" (Chappell, Na- ture, No. .'i46, June 15, 1870). Subsequent to this there are repeated references to the use of a magnetic needle for navigating purposes. As early as the thirteenth century it seems to have been known to the navigators of all European nations, and in 1200 its declination (or roria- tion from the true north) seems to have been