( ) 
be expreilive enough of what is meant by them, and -being 
adapted to too confined an Idea of the Principles of this 
Art. In the old Perfpe&ive the chiefeft regard is had to 
the Ground Plane, that is, the Plane of the Horizon ; 
from whence is derived the Horizontal Line, and by 
means of that Line the Reprefentations of fome Figures 
are found by good fimple Conftru&ions. But then the 
Figures in all other Planes are drawn by reducing them to 
the Horizontal Plane by means of Perpendiculars ; which 
is an inartificial round-abour way, makes a great Con* 
fufion of Lines, and is not capable of fo much Exa&nefs. 
This confined way of treating thisSubjed, proceeds from 
the ftrong Pofleffion the Mind is bred up in . of the Notions 
of Upwards and Downwards, which makes one apt to re- 
fer all other irregular Pofitions to thofe principal ones. 
But the Minds of all Artifls (hould be drawn as much as 
can be from fuch confined Ways of thinking, and they 
fhould be taught to accuftonj themfelves, as much as may 
be, to confider Nature in its general View, withouc 
minding thofe particular Relations which things have with 
refped to themfelves. For this reafon our Author has 
rejected the Term o f Horizontal Line, becaufe it con- 
fines the/ Mind loo much to the particular confideracion 
of theHorizontal Plane : but he. con fid ers all Planes alike, 
and all Figures as they are in themfelves, without confi- 
dering their Relation to us ; leaving the Arcift to do that, 
when he comes to apply the general Rules of pra&ice to , 
any particular Defign. ( ~ 
This Treatife is veryi fhort, becaufe the Author has 
confined himfelf only to give the general Rules of pra-< 
6fice, leaving the Reader to himfelf or to a Matter to find 
out particular Examples to exercife himfelf in. Yet he 
hopes; he has omitted nothing that is material to the un- 
der ftanding of this Art in the full extent of it. The whole : 
Book.confifts.oirfive Sections, 
t ;co B b b 3 
The . 
