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CLOCK 24 CLOTHINa necessary to regulate the weight so as to make the index pass over equal spaces in equal times. This must be accom- plished by a pendulum or escapement of some kind, and a rude escapement is at- tributed to Gerbert, about A. D. 1000. A better one was that of De Vick in 1379. Accuracy in marking time was not at- tained, however, by this, though it was a great improvement. For 270 years there was no advance, but between 1641 and 1658 the idea of attaching the pallets of the escapement to the pendulum-rod and making the escapement horizontal oc- curred both to Harris, an English clock- maker, and Huyghens, a Dutch philoso- pher. The anchor escapement of Dr. Hooke, invented in 1666-1680, and the dead-beat escapement of Graham in 1700, gave a new impulse to clockmaking. There has been no material change in the principles on which clocks are made, except in the substitution of steel springs for weights and in the finer movements, and in the addition of the hairspring to regulate still further the action of the escapement or pendulum, since 1700. There have been a great variety of es- capements invented and much more at- tention paid to accuracy in the details and perfection of finish, but the principles are the same. Considered as scientific instruments for the precise measurement of time, they may be divided into two classes accord- ing to the character of the compensation of their pendulums, whether of the grid- iron type or the mercurial pendulum. The first keeps a constant length of the pen- dulum-rod by the difference of expansion of different metals with change of tem- perature, and the other makes up for the lengthening of the rod with rise of tem- perature by the greater expansion of a jar of mei'cury carried on the bed-plate of the pendulum, the rise in the center of gravity of this counterbalancing the lengtheniHg of the sustaining rod. Clocks differ in another important particular, that of the escapement, whose function it is to be unlocked at each oscillation of the pendulum and thus allow the train of wheels to move forward a step, and also to transmit an impulse to the pen- dulum just sufficient to counterbalance the friction caused by the unlocking of the escapement. In fine astronomical clocks either the Graham dead-beat or some form of gravity escapement is the one most geiTierally used. In any of them the object to be attained is to make the work of unlocking and the impulse given to the pendulum to make up for it as nearly absolutely constant as possible. If this is not done the arc of vibration of the pendulum will vary, and with it the steady rate of the clock. The manufacture of clocks in America began about 1800 in Connecticut, which is still the center of the industry in the United States. CLCELIA, a girl of Rome, who, the legends say, having been given up to Porsena as a hostage, escaped to Rome by swimming the Tiber. CLOQUET, a city of Minnesota, in Carlton co. It is on the Northern Pa- cific, the Great Northern, the Chicago, Milwaukee and St. Paul, and the Duluth and Northeastern railroads, and on the St. Louis river. It is the center of an extensive lumber region and has manu- factures of print paper, boxes, and match blocks. Pop. (1910) 7,031; (1920) 5,127. CLOSURE, a rule in British parlia- mentary procedure adopted in 1887 by which, at any time after a question has been proposed, a motion may be made with the speaker's or chairman's consent "That the question be now put," when the motion is immediately put and decided without debate or amendment. The mo- tion must be supported by more than 100 members and opposed by less than 40, or have the support of 200 members. The introduction of the Closure was in- tended to prevent debates from being too much spun out. In the Congress of the United States the practice has been to allow unlimited debate, and it is for this reason that there are so many instances of obstruc- tionary tactics being resorted to by a minority to delay the passage of a meas- ure. These tactics have been given the general name of "filibustering," and in- clude almost every expedient known to parliamentary tacticians. A call for "the previous question." if sustained, will usu- ally terminate discussion immediately. CLOTAIRE I., son and successor of Clovis (q.v.), first king of the Franks in Gaul, reigned as sole king from 558 to 561. Clotaire II., a king of the same Merovingian dynasty, reigned over the Franks 30 years later. CLOTH, a manufactured substance consisting of wool, hair, cotton, flax, and hemp, or other vegetable filaments. It is formed by weaving or interlacing threads, and is used for making gar- ments or other coverings. The term Cloth, when used alone, is generally em- ployed to distinguish woolen Cloth from fabrics made of any other textile mate- rial. See Weaving. CLOTHING, the clothes or dress, that is, the artificial coverings collectively, which people wear. Nothing is more necessary to comfort than that the body should be kept in nearly a uniform tern-