( 555 )

Spring* be not equajly strong : That thp BaJ lance ot' such, a, Watest will bedouble, and iqay beCharged more or lefijand receive Delay, by Advanqing otRecoiling, along the two Arms two eqval Weights, Counter-baliancirjg oncanother, that lb the Change of the Situation may not at all prejudice tlic.

Eyuality of the H'atch. For the reit, we may in this kind os H'atchct (bare

the Fuße, and consequently the String or Chain. ’Tis also eafie to judge,

that such iViUchcs as these may bc ot a Size (ufficiently small-; that they

will make no more Noise than ordinary Wutches ; that they will be as exact.

as P endulums, and cease not to go whilst they are Winding up. And though

the Motion of theWatch VVheels may be altered by many Acddenis,-. yet . ;

the Pcriodt of the ßmll Springt will not be concerned in all or any of them,

provided the Motion of the Watch VVheels have always more Strength than

ic needs to Bend them again , \yhich is in our Power.

The Objections that have been made against this Contrivance, äs cm- vployed for Finding Longitudcs, are these ; That Toliing of Sliips wotild (hakethe Springt as well as other picces; That Ruft would spoil them, stnoethe Saltifli Humidity of the Sea in remote Voyages, spätes not the veryNccdles of Compafles though incloled in Boxes ; That the Changes of Sea-ions and Climates will sensibly alter the Springt, especially the great Hcatsor Rains within the Tropicks, which at length will sbmewhat Untemper theSteel; as is confirmed by the Experiments, of the Illustriern Acadcmy of Fit s*rence , shewing how eafily that Hcat and Cold do change Slcnder Springt *.besides that, the Air more or Jels Condensed will also more or less resist theMotion of the Ballance. To which may be added, That Springt by work-äng are weakened; And Lastly, Tliat there will be always some little Fritlictr,that will make the several pieces go more or less eafily, and that even inlength of time they will wear out. .1 . ;

But I Answer, That all these Defects, that proceed from the Imperfectaon of the Matter, may be sormounted by a General Remedy, without Exa«-mining them here in Particular: And tliat is, That for execuring ic in »great, we may make use of massy Springs, as are those of Crosi-Bows, wcbeing Masters of them, not wanting Force or Place in a Ship, to govern agreat Weight that may serve to Bend them continually again. Now theseM/tJfy Springt may be so great, and their Restitution lb speedy, by Augment-ing their number, that all the above-named Defects will have no conlido-rable Proportion to this Strength, and the Aggregate of their Reperitiortswill not be sensible till aster a very long kirne. And ’ris easic to Dmosthate,

That by Augmenting the Bignels of the Engine, and the Force of the Mast)

Springt, we may make the Errour as small as we will, proyided we pafs notthe Bounds of convenieocy, and Content our selves with Exactnefs sofft cientfartheir Chief End, vt\. For finding the Longitudet. i’; • v) .T

■ - - * ClostK sccn-

VI. The Circle, FGH, being placed upon a P/ain Inciimd A B, isndi-^nc^» -,'.vided into two Unequal Parts by the Line GI. Torestore to the Less See- tj" mT de Gen-’ture jts rEquIlilirium , there is tastned to the Extremicy of the Radius DF,»a n «*

Weight F, which js sojftcknt-ly.hcaxy to Recover, what the leÖer Sectüre"'

Bbbb'i loses