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the Henry Circle ( or Dial-Plate ) succcssively Culminating over the Point ofthe Index (which is always to keep the fame Position) will fhew the Hours ofthe Day and Night. And when byscveral repeated Revolutions, it has mea-iüred out the length of its Stagc, it is to be replaced at S, as before, whichmay be done in leß thun half the time you are Winding- up a Watch ; andif the Stege be 6 Foot long, no oftner than once in a whole Weck.

^ The way of Adjusting the Motion to the exact Meafure of an Hour,and Rectifving its Errours, is thus: vi%. By the turning of a Skrevv inlertedat S, the Strige may be Elevated or Deprest, and accordingly the Movementwill go Faster or Slower: Faster if Raifed up, and Lio wer, if let Down ;and by making the Horary Circle Moveable, and Inferting feveral finali Boffesor Buttons, here and there upon the Verge thereof, it may with an easietouch of the Finger be moved to the right and lest, as there fhall be occa-sion, till the just Time be brought to the Point of the Sufpended Index.

The Reason of this Movement may be thus Explain’d : i. Let the Circle l67 ‘

L O D N, reprelent any Circular Bödy, whofe Centers both of Gravity andMagnitude are Coincident at M. Let this Circular Body be placed uponforne Level Plain G G, and then ’tis Evident that the Angle of its Contactwith that Plain at a, will also be the Point of its Libratson, and confc-qucntly it must Reit there : Quia Momentum & Impedimentum sunt aqualia. '

z. Let D E, reprefent a Desccnding Plain, making an Angle of Contactwith this Circular-Body at L; and here ’tis manifest it cannot Rest ; becaufethe Line of Dircction r a, which (while it Irrsisted upon a Level) dividedthe Circular Body by the Centers of Magnitude and ' Gravity into PartsAs uiponderate, is now removed to I. D ; which Line L D, siilling vvith-out, or belide, the Center M, cvidently destroys the /Equipoife of its Parts",and therefore must leave it to tumble down towards E. For here Momen-tum Impedimento majus. The Reafcn therefore of its Defcent now, beingthe Over-ballance of the Parts LND-, to the remaining Section LDO;it must necessarily follow :

z. That if forne Weight equal to the Exceß of L N D, above L O D,wercaffixt to the I.imb of the Quadrant O <i, as at P ; then the CircularBody would Rest as Quietly at b, as it did before at a. The Suppositioncannot be denied, and the Confequence is unavoidablc, becaufe LDO+P— L N D. i. e. Impedimentum aquatur Momenta.

Let then the Numbers, i, z, 3, 4, reprefent- a Trairr of Wheel-work,wherein there is no material difference from what is found in a commorrWatch only the numbers of the Teeth on the Wheels and Pinions are tobe so Calculated, that the Motion of the whole Train may corrcfpondto theasligned Revolution of the Body of the Movement , which is to be once in'

14 Hours : It would be Expedient also, That a Spiral Spring were applied to'

'usBallance, as in later Movement s, is ufiial ; but of a Tusce here’s no need,for theTums of the Body of the Movement, as it- defcends upon the St age,answer all the Intentions of a String or Chain ; and the Contranitencc of theWeight P, to the exceß of LED, above LQD, ferves Instead of a Perpetua!

Springg and th« Movement want-s only a lerpatual Dcsccnt, to inake its M)-"

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