Mifcellanea Curiofa. 319 



of it ; which may moft conveniently be engra- 

 ven on the outfide thereof, as a ftanding Directi- 

 on to all Gunners, who (hall from thence for- 

 ward have occafion to ufe that Piece : And were 

 this Matter well afcertained, it might be worth 

 the while to make all Mortars of the like Dia- 

 meter as near as may be, alike in length of 

 Cha(e, Weight, Chamber, and all other Cir- 

 cumftances. 



This Difcovery that the utmoft Range on an 

 inclined Plane, is, when the Axis of the Piece 

 makes equal Angles with the Perpendicular and 

 the Object ; compared with what I have demon- 

 ftrated of the fame Problem in the aforefaid Di£ 

 courle does lead to and difcover two very ready 

 Theorems ; the one, to find rhe greateft Hori- 

 zontal Range at 45-° Elevation, by any Shot 

 made upon any inclined Plane, with any Eleva- 

 tion of the Piece whatfbever And the other to 

 find the Elevation* proper to ftrike a given Ob» 

 ject, with any Force greater than what fuffices to 

 reach it with the aforefaid middle Elevation. 

 Both which being performed by one fingle Pro- 

 portion, may be very ferviceable to fuch as are 

 concerned in the Practice of Gunnery, but are 

 unwilling to trouble themfelves with tedious and 

 difficult Rules. The two Proportions are thefe. 



P KO P. L 



^ A Shot being made on an inclined Plane, ha- 

 ving the Horizontal Diftance of the Object it 

 ftrikes, with the Elevation of the Piece, and the 

 Angle at the Gun between the Object and the 

 Perpendicular; to find the greateft Horizontal 

 Rangeofthat Piece, laden with the fame Charge: 



that 



