2 * ] 
the Meafures made ufe of in 
each Country : Such as were the Stadia of the An- 
cients, and fuch as arc our Miles, Leagues, Werfts, &c. 
And how could different States be compared with one 
another, fo as to come at the Knowledge of the Spaces 
they fevetally occupy on the Earth's Surface, without 
knowing the Number of thefe common Meafurcs 
contain'd in a Degree, or in the whole Extent of the 
Earth? Hence proceeded the twofold Method of de- 
termining the Situation of the different Parts of the 
Earth, either by their mutual Diftances fet down in 
the Meafures made ufe of in each Country, or ex- 
prefs'd in Meafures common to all, as Degrees, Mi- 
nutes and Seconds, by marking the Longitude and 
Latitude of each Place. 
Upon the firft Determination of the Magnitude of 
the Earth in Geographical Meafurcs, as in Stadia and 
Arabian Miles, the Ancients did not employ any 
great degree of Exa&itucfc. They were content to fet 
down the Circumference df the Earth, and of its 
Parts, in round Numbers $ probably, becaufe they 
did not expert to be able to attain much Precifcncfs 
in aRefearch of this Nature. But according as their 
’Defires of improving Geography encreafed, by en- 
tering into a Detail of it, they found it necefiary to 
have a -more exad Knowledge of the Magnitude of 
^cach Degree, not only in great Meafures, as in Miles 
and Leagues, but alfo in Pearches, Toifes and Feet ; 
which could not -be done other wife than by Geome- 
trical Operations and Aftronomical Observations, 
more exaft, andcorafequentlytnoreoperofe, than had 
*been, or indeed could have -been undertaken before. 
- - id ■" i 
■X. \ 
their true Diftances, 
[ 
by 
