190 Mechanick Powers. Book IX.

Of all Men; and ſince there are divers ways of application inthis kind, ſome hereof we have deſcribed juſt before, it re-mains that we reckon up ſome others in this place, either moreingenious, or alſo more uſeful.

Fig. 132. Let there be a Pendulum I L , with a wire fixt tothe Axis C D, wliich reſts on the two poles C and D, and inthe middle part of its Axis, faſten here and there two littlewings, or thin plates of mettal, extended according to thelength of the Axis, or in an Horizontal ſite, above this Axis letthe upper wheel of the Clock A B be turn'd, being made bya peculiar art; to wit, let it be made in form of a Zone, wicha double row of Teeth diſpoſed to the end of the Zone in ſucha double order, that when the Teeth, or little Keys. that ſtandout, being conſiderably diſtant from one another, each toothof one row, anſwer to the middle ſpace of teeth of the otherrow; for ſo by turns they will hit againſt the aforeſaid twowings, to wit, one tooth or little key of the row towards theright hand, op the righ wing, and the other row on the lefthand, on the left wing; again, the other on the right, on theright wing, from whence are made the Altern Vibrations of thePendulum . If then each of the two rous conſiſts of. ten teeth,in all they will make twenty; and the Pendulum muſt be offuch length, chat each compoſed Vibration anſwers one ſecondof time, there may be fitted on the ſame Axis of the wheel theTympane F with ſix teeth, which will be moved by the wheelG H of 36 tceth, for this will abſolve one circuit in the ſpaceof a Minute; ſo that an Index faſtned to its Axis, may noteevery ſecond in a circle divided into 60 equal parts; and be-neath the Wheel G H, another may be fitted, which may beturn'd about in the ſpace of an hour, and its Index may ſhewG0 minutes, moreover another which may ſhew the Hours,

CC.

But ſometbing offers it ſelf worth our noting in the appli-cation of Pendulums to Clocks; in the firſt place, if a weightdoubley or tripley greater be hanged to a Clock, it is not thereaſon of moving it notably ſwifter, or the cauſe of makingthe hours viſibly ſhorter, becauſe in this caſe the Pendulum 18 forced more vehemently, and therefore makes greater archesin its Vibrations; it ſeems that it ought to move more ſlowly,and to make the hours longer, if it be true that is ſaid in theBook of Pendulums, that the Vibrations which are made in a

greater