Mifiellanea Curiofa. 3*3 



may the comparative Force of a Shot in any two 

 Points of the Curve, be either Geometrical!} or 

 Arithmetically difcover'd. 



Corollary. 



i?rom hence it follows, that the force of a Sho£ 

 is always Ieaft at U, or the Vertex of the Para- 

 bola, and that at equal diftances therefrom, as at 

 T and X, G and B its force is always equal, and 

 that the Ieaft force in U is to that in Gand B, 

 as Radius to the Secant of the Angle of Elevation 

 FGB. 



Thefe Proportions confidered, there is no que- 

 ftion relating to Project, which, by the help of 

 them, may not eafily be Solved ; and tho ? it be 

 true that mod of them are to be met withal, in 

 Galileut, Torricellius and others, who have taken 

 them from thofe Authors, yet their Books being 

 Foreign, and not eafy to come by, and their Dc* 

 monflr-ations long and difficult, I thought it not 

 amifs to give the whole Dctlrine here in Bmlifh. 

 With fuch fhort Analytical Proof of my own, as 

 might be fufficient to evince their Truth. ' 



The Tenth Propafition contains a Problem, un- 

 touch'd by Torricellius, which is of the greateft 

 ufe in Gunnery, and for the fake of which this 

 Difcourfe was principally intended : It was firft 

 Solved by Mr. Anderfon, in his Book of the Ge- 

 miine Ufe and Effe&s of the Gun, Printed in the 

 Year 1674 .5 Dut his Solution required fo much 

 Calculation, that it put me upon /earch, whether 

 it might not be done more eafily, an d thereupon 

 in the Year 1678 I found out the Rule I now 

 Publifh, and from it the Geometrical Conftru&ion % 

 Sine© which time there has a large Tremifi ofthfc 



Y % Subje& 



