(A. Bo.*)
CARDINAL VIRTUES (Lat. cardo, a hinge; the fixed point on which anything turns), a phrase used for the principal virtues on which conduct in general depends. Socrates and Plato (see Republic, iv. 427) take these to be Prudence, Courage (or Fortitude), Temperance and Justice. It is noticeable that the virtue of Benevolence, which has played so important a part in Christian ethics and in modern altruistic and sociological theories, is omitted by the ancients. Further, against the Platonic list it may be urged (1) that it is arbitrary, and (2) that the several virtues are not specifically distinct, that the basis of the division is unsound, and that there is overlapping. It is said that St Ambrose was the first to adapt the Platonic classification to Christian theology. By the Roman Catholic Church these virtues are regarded as natural as opposed to the theological virtues, Faith, Hope and Charity. Some authors, combining the two lists, have spoken of the Seven Cardinal Virtues. In English literature the phrase is found as far back as the Cursor Mundi (1300) and the Ayenbite of Inwit (1340).
See B. Jowett, Republic of Plato (Eng. trans., Oxford, 1887, Introd. p. lxiii); Plato, Protagoras (329-330); Aristotle, Nicomachean Ethics, vi. 13. 6; Th. Ziegler, Gesch. d. chr. Eth. (2nd ed.); H. Sidgwick, History of Ethics (5th ed.), pp. 44, 133, 143; and Methods of Ethics, p. 375.
CARDING, the process of using the “card” (Lat. carduus, a thistle or teasel) for combing textile fibrous materials. The practice of carding is of such great antiquity that its origin cannot be traced. It consists in combing or brushing fibres until they are straight and placed in parallel lines; in doing this, imperfect fibres are separated from perfect ones, all impurities are removed, and the sound fibres are in condition for further treatment. The teasels once used have long given place to hand cards, and these in turn to what, in the rudest form, were known as “stock cards,” namely, two wire brushes, each 4 in. broad by 12 in. long, and having teeth bent at a uniform angle. One was nailed upon a bench with the teeth sloping from the operator, the other was similarly secured upon a two-handled bar with the teeth sloping towards the operator. The material to be treated was thinly spread upon the fixed card, and the movable one drawn by hand to and fro over it. When sufficiently carded, a rod furnished with parallel projecting needles, called a “needle stick,” was pushed amongst the card teeth to strip the fibres from the comb. The strip thus procured was rolled into a sliver and spun. James Hargreaves, the inventor of the spinning jenny, suspended the movable comb by passing two cords over pulleys fixed in the ceiling and attached balance weights to opposite ends of the cords. This enabled him to lengthen the cards, to apply two or three to the same stock and to manipulate the top one with less labour, as well as to produce more and better work. In May of 1748, Daniel Bourn, of Leominster, patented a machine in which four parallel rollers were covered with cards, and set close together. Fibres were fed to the first rotating roller, each in turn drew them from the preceding one, and a grid was employed to remove the carded material from the last roller. This introduced the principle of carding with revolving cylinders whose surfaces were clothed with cards working point to point. In December of the same year Lewis Paul, of Birmingham, the inventor of drawing rollers, patented two types of carding engines. In one, parallel rows of spaced cards were nailed upon a cylinder which was revolved by a winch handle. Beneath the cylinder a concave trough had a card fixed on the inside, so that as the fibres passed between the two series of teeth they were combed. This was the origin of “flat-carding,” namely, nailing strips of stationary cards upon transverse pieces of wood and adjusting the strips or flats by screws to the cylinder. In 1762, the father of Sir Robert Peel, with the assistance of Hargreaves, erected and used a cylinder carding engine which differed in some important particulars from Bourn’s invention. But although roller-carding and flat-carding are the only principles in use at the present time, to Sir Richard Arkwright belongs the merit of introducing an automatic carding engine, for between the years 1773 and 1775 he combined the various improvements of his predecessors, entirely remodelled the machine, and added parts which made the operation continuous. So successful were these cards that some of them were in use at the beginning of the present century. Notwithstanding the numerous and important changes that have been made since Arkwright’s time, carding remains essentially the same as established by him. (See [Cotton-spinning Machinery].)
(T. W. F.)
CARDIOID, a curve so named by G.F.M.M. Castillon (1708-1791), on account of its heart-like form (Gr. καρδία, heart). It was mathematically treated by Louis Carré in 1705 and Koersma in 1741. It is a particular form of the limaçon (q.v.) and is generated in the same way. It may be regarded as an epicycloid in which the rolling and fixed circles are equal in diameter, as the inverse of a parabola for its focus, or as the caustic produced by the reflection at a spherical surface of rays emanating from a point on the circumference. The polar equation to the cardioid is r = a(1 + cos θ). There is symmetry about the initial line and a cusp at the origin. The area is 3⁄2πa², i.e. 1½ times the area of the generating circle; the length of the curve is 8a. (For a figure see [Limaçon].)