( 554 )

Pocket, and when made greater, will be useful to find tlie Longitudet both by"Sea and Land.

Byitr, Goth. x. The Principle I thought upon (bme Years ago for making ExactStr*' Le * b ~ Portable Watchcs , is altogether different from that of M. Hugens ; His de-n. 113. f. 285. pending upon a Physical Observation, but mine upon a meer MechanicalReflection; which hath not been taken notice of for want of the Art ofCombination , the use of which is far more genera 1 than that of Algebra.For, having considered with nty seif, that a Spring being Bent to theseme Degree, will always Unbend it seif in the seine Time, provided it findthe ßme freedom of Unbendmg it seif seuddenly; I inferred from thence,that there mighc be imploycd two such, onc of which fltould play, whilllthe First Mover of the H'atch did Bend the other again.

These Thoughts I have exefcuted in the following manncr : Let A B, bcFit- ‘ 6 a- one of the 0 r atch-Platct , C and M, two Indented Barrels, wherein the (mallSpringt are inclosed. The Teeth of the Barrels catch those of the Pinions4 4, which carry the Ballances c e, and other Teeth of the seid Barrels arecatch cd by those of the Interrupted Whcel F G. Now let us imagine, thatthis VVheel F G, being moved towards H F, by the force of the FirstMover of the PVatch, and turning the Barrel C, Bends the Spring inclosedin it, and ffops with the Barrel as soon as it hath Bent this Spring. Thispiece 'which ferves to stop, is easie» and hath not been thought neeefsery tobe marked here, to avoid embaraifing the Figure. But whilll one Indentedpart of the Interrupted Whecl F G, vi%. F, turns the Barrel C, the emptypart, opposed thereunto, which is G, anlwers to the other Barrel M, andgives Liberty to the Spring, it incloseth, to Unbend it seif. Thus whilllthe Movctnent of the tVatch Bends the (mall Spring of the Barrel C, inthe seme Time the (mall Spring of the other Barrel M, Unbends of it seif.I sey, in the seltne Time, except the Spring C, (hall have done Bending asittle sboner, than the Spring M, {hall have Unbent. it seif: So that the.Spring C, being Bent, and the VVheel F Cr stopped ; both of them stay inthis Posture, till the Spring M, when it (hall be quite Unbent, do, at theend of its Motion, touch a piece which delivers it. And then the Spring CUnbends of it seif in its turn ; the Teeth of the Interrupted Whecl, whichcontinues its Motion the seme way as before, sincc ’tis delivered, not beingany more able to hinder it therefrom, because the Barrel G, doth now meetwith the Empty part H, of the seid WheeL But before it hath done withUnbending it seif, the Indented part L, being opposite to the Empty partH, that tu»ns the Barrel M, Bends its Spring again, and having done so,stops with it; whilst the Spring C, making an end of Unbending it (elf, de-livers them by a Reciprocal good Office, and renders to the Spring M, theseme Services which it had reccived from it, with an Expectation of reeeivingthe like again.

Which being well considered, ’tis manifest, That the seme AlternativeMothns will continue always : That the Periods, taken from the very Mo-ment that one Spring begins to Unbend, until the Moment it onee Unbendsit fclf again, will always be of Etjual Duration , though the two (mall

Springt