12- 
Fig. KXV. 
New Principles of Gardening. 
PROBLE™M TI. 
O defcribe a Circle of any poffible Magnitude required. 
EFtnition: (1.)A Crrcve isa plain Figure, bounded with 
cm Lime, called ie Circumference, in the Midft whereof is 
a Point, from whence all Lines drawn to the Circumference 
are equal, which Point is called the Center thereof, as a. (2) 
The ‘Diameter of a Circleis a Right Line (bc) paffing through 
the Center a, terminating at each End with the Cercumference, 
and dividing the Circle into two equal Parts. (3.) The Ra- 
dius of a Circle is the Semidiameter, as 6a, orac. (4.) A 
Semicircle is the Figure (6”¢) contain’d between the Diameter 
and half the Circumference. (5.) A Segment of a Citcle. Vide 
Pros. XY. Sect. I. 
Practice. ACixcve is ufually defcribed by the Revolution 
of a Right Line, having one of its Ends fix’d on the Center, 
while the other revolves round the fame; as if 74 was fix’d 
at b, (as the Joint of a Sector, Two-foot Rule, Sc.) and to be 
moved from d to 4, to”, to v, and to-d, its former Po/fition, 
the End of the Line d would defcribe the Circumference, and 
the Line the Circle itfelf. When a Circle is defcribed by Com- 
paffes, the Diftance between the two Pozts or Legs ‘thereof, 
is to be confidered as the Radius or Right Line aforefaids =It 
often happens, that Czrc/es are required to be defcribed where 
tis not poffible for the Radius to move round its Center, as 
sia and therefore at fuch Times obferve the following 
ule: 
rigxxvi,_ How to aefersbe aCiacix without the Center being known ; 
i 
et dog be the given Diameter, which bife&t in 6, and there- 
on raife the Perpendicular 64, which make equal to 6 d. Con- 
tinue 6d towards f, and make fd equal to two Sevenths of 
46; on 4, with the Interval 6 deferibe the Arch fm at Plea- | 
fure, make .6v equal tob4 or bd; on d, with any Interval 
greater than half d/, deferibe the Arches £4, ss, on J, the 
Arches 22, and draw 46, cutting the Arch fm in a3 then 
with the Interval dc, or 4a, on deferibe the Arch 00, on” 
the Arches pp, rv, and on v the Arches 9g, tt; interfeCting 
* each 
