STEERING

, in Navigation, the art of directing the ship's way by the movements of the helm; or of applying its efforts to regulate her course when she advances.

The perfection of Steering consists in a vigilant attention to the motion of the ship's head, so as to check every deviation from the line of her course in the first inslant of its motion; and in applying as little of the power of the helm as possible. By this means she will run more uniformly in a straight path, as declining less to the right and left; whereas, if a greater effort of the helm be employed, it will produce a greater declination from the course, and not only increase the difficulty of Steering, but also make a crooked and irregular path through the water.

The helmsman, or steersman, should diligently watch the movements of the head by the land, clouds, moon, or stars; because, although the course is in general regulated by the compass, yet the vibrations of the needle are not so quickly perceived, as the sallies of the ship's head to the right or left, which, if not immediately restrained, will acquire additional velocity in every instant of their motion, and require a more powerful impulse of the helm to reduce them; the application of which will operate to turn her head as far on the contrary side of her course.

The phrases used in Steering a ship, vary according to the relation of the wind to her course. Thus, when the wind is large or fair, the phrases used by the pilot or officer who superintends the Steerage, are port, starboard, and steady: the first of which is intended to direct the ship's course farther to the right; the second to the left; and the last is designed to keep her exactly in the line on which she advances, according to the intended course. The excess of the first and second movement is called hard-a-port, and hard-a-starboard; the former of which gives her the greatest possible inclination to the right, and the latter an equal tendency to the left.—If, on the contrary, the wind be scant or foul, the phrases are luff, thus, and no nearer: the first of which is the order to keep her close to the wind; the second, to retain | her in her present situation; and the third, to keep her sails full.

STELLA. See Star.

STENTOROPHONIC Tube, a Speaking Trumpet, or tube employed to speak to a person at a great distance. It has been so called from Stentor, a person mentioned in the 5th book of the Iliad, who, as Homer tells us, could call out louder than 50 men. The Stentorophonic horn of Alexander the Great is famous; with this it is said he could give orders to his army at the distance of 100 stadia, which is about 12 English miles.

The present speaking trumpet it is said was invented by Sir Samuel Moreland. But Derham, in his PhysicoTheology, lib. 4, ch. 3, says, that Kircher found out this instrument 20 years before Moreland, and published it in his Mesurgia; and it is farther said that Gaspar Schottus had seen one at the Jesuits' College at Rome. Also one Conyers, in the Philos. Trans. number 141, gives a description of an instrument of this kind, different from those commonly made. Gravesande, in his Philosophy, disapproves of the usual figures of these instruments; he would have them to be parabolic conoids, with the focus of one of its parabolic sections at the mouth.—Concerning this instrument, see Sturmy's Collegium Curiosum, Pt. 2, Tentam. 8; also Philos. Trans. vol. 6, pa. 3056, vol. 12, pa. 1027, or Abridg. vol. 1, pa. 505.

STEREOGRAPHIC Projection of the Sphere, is that in which the eye is supposed to be placed in the surface of the sphere. Or it is the projection of the circles of the sphere on the plane of some one great circle, when the eye, or a luminous point, is placed in the pole of that circle.—For the fundamental principles and chief properties of this kind of projection, see Projection.