for Gardeners, &c. ij 



§ 9. Having put down what feems to be moft necefla- 

 ry relating to Lines, I come now to Ihew how thefe Lines 

 produce fuperficial Figures. 



PROPOSITI ON L 



^nd firft tow to frame a Triangle equilateral, upon a /Irait 



Line given. 



From the End A, and the Interval A B, defcribe the 

 Arch B D J and from the End B, and the Interval B A, 

 defcribe the Arch A E ; and from the Se£lion C draw the 

 Lines C A, C B; and ABC Ihall be the equilateral 

 Triangle demanded. Fig. i, 



PROPOSITION II. 



But tecaufe there are feveral Sorts of Triangles, I Ihall 

 in this PropoHtion fhew, how to male a Triangle from any 

 three given Lines, fpippopng A B C. Fig. 2. 



Draw the ftrait Line D E, equal to the Line A A, from 

 the Point D, and from the Interval B B ; defcribe the 

 ArchG F ; from the Point E, and from the Interval C C, 

 defcribe the Arch H I , from the Se£lion 0,draw the Lines 

 O E,0 D; the Triangle DEO, Ihall be compriz'd of 

 three right Lines, equal to the tliree given Lines ABC. 



'^' ^* PROPOSITION IIL 



Hm to frame a Square upon one right Line given and hounded. 

 Elevate the Perpendicular A C from the Point A de- 

 fcribe the Arch B C ,* from tlie Points B C, and from the 

 Interval A B make the Section D -, from the Point D 

 draw the Lines D C, D E j and A B C D Ihali be the 

 Square demanded. 



VraUice on the Ground, 

 This is fo eafy, and fo like the Practice on Paper, it 

 need not be repeated ; however, 1 have put down the Fi- 

 gures, and Ihcwn the Method of making a Square upon 

 the Ground, and Ihall add, 



PROPOSITION IV. 



The Way to prove a Square, 

 Which is indeed only by meafuring Diae[onaI or Croft- 

 Ways 5 and if the Meafure (fuppofing 50 Foot) is exactly 

 alike, you may conclude your Square is true. l^^H, Fig. 

 4, and 7. Other wife it is falfe. 



