PKACTICAL DIAQBAMS. 



Fig. 8. 



tlic ends of (lie oval ; tlio iiitorsocliiij,' points of these 

 c'iirlos will be centers to tlic two seirrneiits recjuired to 

 complete the figure 8. 



To describe an oval, when the longlli and breadth are 

 both given, lay down the 

 length and breadth pcri)en- 

 dicular to each other ; com- 

 bine a and d ; measure the 

 distance from c d, on the line a c from r, which will give 

 c n ; measure the distance from n a, on the line d a, 

 which will give/; divide /a into two equal parts, at 

 the middle of which erect a perpendicular: wliere that 

 perpendicular cuts the line a h will bo the center A, for 

 the end of the oval ; and where it cuts the line d i at g, is the center for the side, (fig. 9.) 

 The gardener's oval, when both the length and breadth are given, is thus formed : 



Set oif the length a b, and breadth c d, 

 perpendicular to each other ; take half 

 the long diameter, and measure from c, 

 to the line a b, with that length; when 

 tliat line cuts the line a b, put in a peg ; 

 ?- /---.=!:..':l' qI \o „ do the same on the other side, and the 



Fig. 



~~"^>fe 



lb point e will be found; stick in there also 

 a peg ; then, with a cord passing round 

 the pegs i e and c, with the addition of 

 the space from a to e, describe tlie figure 

 with the peg c. (Figure 10.) 



To form an egg-shaped figure (fig. 11), 



the line a b being given, divide it into two equal parts ; from the point c, where 



these lines intersect each other, construct a 



circle with the radius ca or cb; draw the 



line c d perpendicular to a 5; taking a and b 



as centers, describe two arcs ; draw a line 



from b through d, till it cuts the arc at /; 



then, with J /as a radius, complete the figure. 



To set off a walk 

 perpendicular to the 

 line c d. — From the 

 center e on the line 

 c c/ set oflf e <7 and 



--•*-■**-- 



Fig. 11. 



/y e y 

 Fiff. 12. 



\ e h, at equal distances. From the points k g draw two arcs 

 I of different radii ; if, where these arcs bisect each other, a 

 -J,/ line be drawn, it will be perpendicular to c d. Bj the same K 

 rule the center of a walk will beHbund perpendicular to the V^ 



