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of a Shot in any two Points ofcthe Curve, be either Geometncalfy or Arith-metically difcovered.

Co»-#//.] From henceit follows, That the Force of a Shot is ahvays lea st at V,or the Vertex of the Parabeln, and that at Equal Distances therefrom,as at T and X,

G and B, -its Force is ahvays Equal, and that the least Force in V, is to thatin G and B, as Radius to the Secant of the Angle of Elevation, F G B.

The Tentb Propofition contains a Problem , untouch’d by T brricclliui, whichis of the Grcatest Use in Gunnery, and for the salte of which this Difcourfewas principally intended. It was first Solved by Mr. Anderfon, in his Bookof the Genuine Vse and llffefts of the Gun, Printed in the Year 1674..but his Solution required sb much Calculation, that it put me upon Search,whether it might not be donc more eafily ; and thereupon in theYear 1678. I so und out th cTfule I now Publish, and from it the Geome-trica! Contsruction : Since which time, there has a large Treatife of thisSubject, Intituled, idArt de Jet ter les Bombet, been Publifh’d in France byM. Blu/hlei, wherein he gives the Solutioni of this Problem, by Meiiie.urs Bout,

Homer, and de Ia Hi re ; But none of them are the fame with mine, or in myOpinion more ealie.

It was formerly the Opinion of those concerncd in Artillery, That there 21Ä. p.was a certain requisite of Poxvder for each Gun, and that in Mortart, wherethere Distance was to be varied, it must be done by giving a greater orleiser Elevat ion to the Piecc. But now our Later Expcrience has taught us,

That the fame thing may be more Certainly and Readily performed, by In-creafing and Diminifhiug the Quantity of Poxvder, whether regard be had to theExecution to be done, or to the Charge of doiog it. For when Bombt areDilcharged with great Elevationi of the Mortar, they fall too Perpcndicular,and Bury themselvcs too deep in the Ground, to do all that Damagc theymight, if drey came more Oblique, and Broke upon or near the Surface otthe Earth ; which is a thing acknowledged by the Besicgcd in all T 'oxvni, whoUnpave their Streets to let the Bombi Bury themfelves, and thereby stifle theforce of their Splinters. A Sccond Conveniente is, That at the Extream Ele-vatio», the Gunner is not obliged to be so curious in the Direction of hisPiecc, but it will suffice to be within a Degree or two of the Truth; whereasin the other Method of Shooting, he ought to be very curious. But a Thiriand no lesi considerable Advantage is, 'in the saving of the KJngt Poxvder,which in (b great and sb numerous Dischargct, as we have lately seen, must'needs amount to a considerable 'Value. And for Sea Mortart it is scarccPracticable otherwise to use them, where the Agitation of the Sea continu-ally Changes the Direction of the Mortar, and would rentier the Shot Veryuneertain, were it not that they are placed about 45’°. Elcvation, where se-veral Dcgrees above or under makes very little diftereqcein the Effect.

It only remains by Good and Valid Experimenti to be assured of the,Porce ^

of Gun-Poxvder ; How to make and conserve it equal ; And to knowtheEf-.fect thereof in each Pcies^ that is, How far diftering C bärget will cast thefame Shot out of it; which may möst conveniently be Engraven on tbeoutr .. ■

fide thereof, as a standing Direction to ali Gunner 1, \vho ffiall from thence

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