Page:Encyclopædia Britannica, Ninth Edition, v. 6.djvu/253

Rh Most of the companies administer charities of large but unascertained value. Many of them are governors of important schools, e.g., the Skinners have the Tonbridge Grammar School; the Mercers, St Paul’s School; the Merchant Taylors, the school bearing their name, &c. There is no exact information to be had as to the value of these trusts, or the manner in which they are administered. The History of the Twelve Great Livery Companies, by W. Herbert (London, 1837), may be referred to on this subject. Admission to the companies is now subject to the payment of considerable fees. For example, in the Merchant Taylors the fees are—Upon taking up the freedom, by patrimony or servitude, £1, 3s. 4d., by redemption, £84; on admission to the livery, £80, 8s.; on election to the Court of Assistants, £115, 10s. The hospitality of the companies is well-known. The advantages of being a member, still more of being a liveryman or assistant, of one of the rich companies are doubtless considerable. There are indications that the position of the city companies is likely to be for some time to come the subject of political discussion. It may be briefly said that they are being threatened on two sides—on one side by those who desire to see extensive reforms in the municipal organization of the metropolis; and on the other by those who wish to carry forward the process of inspection and revision of endowments, which has already overtaken the universities, schools, and other charities. COMPARATIVE ANATOMY is the term employed to express that branch of anatomy in which the construction, form, and structure of two or more animals are compared with each other, so as to bring out their features of similarity or dissimilarity. It is sometimes used, in contrast with the term human anatomy, to signify the anatomy of the lower animals, but this is an imperfect and inexact use of the term, as the anatomy of man may be made comparative when it is examined in comparison with that of animals. The study of comparative anatomy is of especial importance to the physiologist, the embryologist, the veterinarian, and the zoologist. To the physiologist because, from the comparison of the bodies of different animals with each other, modifications in the size, form, and structure of any particular organ can be traced, and conclusions can be drawn on the importance of the function of the organ in the economy. Moreover, with a knowledge of comparative anatomy, the physiologist can conduct experiments on animals which have organs similar in structure to those of man, and determine their function more precisely than would be possible in the human body. To the veterinarian a knowledge of the comparative anatomy of the domestic animals is essential to the study of their diseases. To the embryologist, a knowledge of the anatomy of different animals throws light on the signification of the structural changes which the body of any particular animal passes through in the course of its development. To the zoologist, a knowledge not only of the external form but of the internal structure of animals is essential in order that he may frame a precise system of classification. In the present work the anatomy of the different great classes and some of the more important orders of the animal kingdom is arranged under special heads that of the amphibia under, of birds under, of monkeys under , &c. See also,. and.  COMPASS,, consists of three principal parts,—the card, the needle on its lower surface, and the case. The whole is enclosed in the compass-box, or binnacle. The term compass is said to have been applied to the instrument because the card involves or the compasses whole plane of the horizon, or because the needle indicates the whole circle of possible variations of direction. The surface of the card is divided by radiating lines into 32 parts, each containing 11° 15ʹ; these constitute the 32 points or rhumbs; the half-points and quarters are subdivisions of the same. The north pole is denoted on the card a by fleur-de-lis ; and the line which joins the north and south poles passes through the axis of the needle. The points are named according to their to the four cardinal proximity points; for instance, the point mid-way between N. and N.E. is called north-north-east, being nearer north than east, and is marked N.N.E; the point mid-way between N. and N.N.E. is termed north by east, and is marked N. by E. The circumference of the card is sometimes divided into 360°. The divisions of the card are shown in the accompanying figure. The card is directed by the needle, Compass card.png. 1.—Compass Card. which, with it, is pivoted on a vertical axis. With a little variation, the needle points nearly to the geographical north, and hence the mode of steering by the compass. Four or more parallel magnets, with like poles pointing in like directions, may be combined to form the needle; and by this arrangement the magnetic moment is increased for a given weight of steel. The needle is usually suspended on a central cap of ruby or agate, the point of suspension being of a similar hard material. On the inside of the compass-box is a vertical line known as lubber’s point; and since this and the pivot of the card are in the same plane with the ship’s keel, the point on the circumference of the card opposite to lubber’s point shows the angle the ship’s course makes with the magnetic meridian. The compass is kept horizontal by the use of a gimbal, or ring moving freely on an axis, within which it swings on an axis at right angles. In the azimuth compass the circumference of the card is divided into degrees and parts by a vernier, and is fitted up with sight-vanes to take amplitudes and azimuths, for the purpose of determining the variation of the compass by observation. The variation is applied to the magnetic course shown by the steering compass, and thus the true course with respect to the meridian becomes known. The conditions that chiefly affect the use of the mariner’s compass are those of the magnetic declination and deviation. The declination is the angle contained between the geographical or true and the magnetic meridian; or, as Barlowe defines it, the swerving of the pointing of the magnetical needle in the horizon from the meridian line there. The angle of declination varies according to locality, and must be ascertained at sea by means of the