22 a Gen. Roy’s Account of . 
the latitude of Dunkirk nearly, we have, as T : 61247 :: 
e° 1 o''. 1 7 : 9 1 j 75.3 fathoms = the arc DR. 
But the length of this arc DR has been found nearly the 
fame, that is, 91176.3 fathoms (fee the table of general re- 
fults) by continually drawing parallels to the meridian of 
Greenwich through the different Rations between it and Dun- 
kirk 5 therefore, although that method in general is not Briefly 
accurate, having a tendency to give the relults in excels; yet 
it is evident, that the length of the arc of a great circle lo 
determined will differ very little from the truth, when the 
ieries of triangles employed for that purpofe are contiguous to 
it, and follow its diredtion nearly. 
Art. XIII. For the dijlance between the parallels of latitude of 
Greenwich and Paris. 
The diftance between the parallels of Greenwich and Paris 
has already been determined in Art. X. of this fedtion, by 
taking M (1420.41 toifes weftward from Dunkirk) as the in- 
termediate point. Let us next fee what will be the reiult when 
Dunkirk is made ufe of inftead of M ? 
In fig. 10. as cof. RD : rad. cof. DP : cof. PR=38 56' 
24^.07 ; but DP by obfervation is = 38' 57' 50 // .7 = PW; 
hence PW-PR = 38’ 57' S°"- 7 ~ 3 ^ 5 6 ' ^".oy = i' 26 '.63 
— RW — 1464.5 fathoms nearly, by taking 60858 fathoms for 
a degree of the meridian, that being nearly its value in the 
latitude of Dunkirk. 
By our operation Dunkirk is 25425 fathoms fouthward from 
Greenwich ; but the great circle DR meets the meridian of 
Greenwich about 8§ fathoms further fouth, that is to fay, GR 
is 25425 + 8.5 =; 25433.5 fathoms, which being added to 1 464.5 
gives 
