periodic (periodik)

[OF. periodic, F. pé riodique = Sp. periódico = Pg. It. periodico D. periodiek ( cf.G.periodisch -Dan.Św.periodisk), the periodic motions of the planets round the sun, or of the moon round the earth.-3. Happening or occurring at regularly recurring in tervals of time; statedly recurring: as, a pe riodic publication; the periodic return of a plant's flowering; periodic outbursts; the peri odic character of ague; the periodic motion of a vibrating tuning-fork or musical string. Periodic gatherings for religious rites, or other public purposes, furnish opportunities for buying and selling, which are habitually utilized. H. Spencer , Prin. of Sociol., § 497. 4. In rhet.: (a) Of or pertaining to a period or complete sentence; complete in grammatical structure. (b) Noting that form of sentence in which the sense is incomplete or suspended until the end is reached. These principles afford a simple and sufficient answer to the vexed question as to the value of the periodic sentence or sentence in which the meaning is suspended till the end-as compared with the loose sentence, or sentence which could have been brought to a grammatical close at one or more points before the end. A. S. Hill , Rhetoric, p. 152. Milton is the last great writer in the old periodic style. J. W. Hales, Int. to Milton's Areopagitica, p. xxxiv. Doubly periodic, having two periods. - Doubly periodic functions, in math. See function. - Periodic comet. See comet, 1. - Periodic continued fraction. See continued fraction, under continued. - Periodic curve, fever, etc. See the nouns. Periodic function. This phrase is used in different senses in the calculus of functions and in the theory of functions. In the former, a pe Shak., 1 Hen. VI., iv. 2. 17. About foure of the clocke, they made a period of that solemnity. Coryat , Crudities, I. 39, sig. D. To end And give a timely period to our sports, Let us conclude them with declining night. B. Jonson, Cynthia's Revels, v. 3. riodic function is one whose operation being iterated a Hence-51. The end to be attained; goal. This is the period of my ambition. Shak., M. W. of W., iii. 3. 47. 6. In rhet., a complete sentence from one full stop to another; a pa age terminated by a full pause. I am employed just now in translating into my faint and inefficient periods the divine eloquence of Plato's Symposium. Shelley, in Dowden, II. 218. 7. In anc. pros., a group of two or more cola. According to the number of cola it contains, a period is dicolic, tricolic, tetra colic, etc. The end (apo thesis) of a period must coincide with the end of a word, and is also characterized by admitting of syllaba anceps and hiatus. A single colon treated thus is also regarded as a period (a mono colic period). A mono colic, dicolic, etc., period is a meter. (See meter2, 1 (b) (2).) Certain periods are known as lines or verses. (See line2, 6 (b).) A group of periods is called a system. certain number of times restores the variable. Thus, 1-x is such a function, since 1-(1-x) = x. But in the theory of functions a periodic function is defined as a function having a period. For a more general definition, see func tion. Periodic inequality, a disturbance in the motion of a planet dependent upon its position in its orbit relative to another planet, and hence going through its changes in periods not exce ively long: opposed to secular ine quality, which is a disturbance dependent upon the relative positions of two planetary orbits. - Periodic law, in chem., a relation of chemical elements expre ed by the statement that the properties of the elements are periodic functions of their atomic weights. If the chemical ele ments are arranged in the order of their atomic weights, at regular intervals of the series will be found elements which have similar chemical and physical properties - that is, there is a periodic recurrence of these properties. If the elements showing this periodic recurrence are arranged in order by themselves, they form a group which, having similar properties and relations, follows a regular progre ion in the individual differences of its members. - Periodic stars. See star. - Periodic winds. See monsoon and trade - wind. of a composition, usually consisting of two or more contrasted or complementary phrases; a complete musical sentence. The term is somewhat variously used; but it always involves a cadence at the end of the period, by which it is distinctly separated from what follows. Usually a period includes eight or sixteen + -al.] I. a. 1. Having a period; performed in a fixed period or cycle; appearing, occurring, or happening at stated intervals; regularly or statedly recurring at the end of a fixed period of time: as, periodical diseases; periodical publications. or regularly recurring intervals: as, a festival celebrated periodically. The