[ 7 5 « ] 
be put on at one time, meeting in the Centre of 
the Table. 
Each Chart is always crofled by Right Angles 
through the Middle, for the Purpofe above, and to 
make any of them anfwer to the Guide-Lines on the 
Table, Fig, i. IK, LM, drawn quite through the 
Centre, and the whole Table. So the grand Ob- 
jection of fhifting Papers is obviated. 
Its Facility and Difpatch , 
As alfo its Certainty, compared with any of the 
mod celebrated Inftruments, I fhall now briefly fet 
forth. 
But, in order thereto, it may not be improper to 
to premife, or lay down, as Lemmata , thefe Three 
Things : 
1. The effential Bufinefs or Aim in purveying of 
Lands or Countries , is either to have an 
exaLt Flan , or to find the Area in fome known 
Me aj lire . 
2. Every thing that is fuperfluous or foreign to 
fitch FOefign, is better omitted than taken . 
3 . If a true Survey , and exahl Flan be made , 
every Fart will have its jufi Froportion , 
and every Angle its true Opening or Quan- 
tity. 
Then what need have we of Degrees, Minutes, 
&c. ? They are never made any Ufe ot in the 
Practice of calling up, or any thing related thereto : 
For, if from a Station Two Lines be drawn by a 
good Index to Two diftant Objects, will it not be 
the 
