the Trigonometrical Operation, t$7 
alfo 358,6 fathoms for the fpace that M is font h ward from 
Dunkirk. But the diftance of Dunkirk from the Royal Ob- 
fervatory at Paris, given in the 276th page of M. Cassini de 
Thury’s Book, when reduced in the proportion of the two 
bafes becomes 133765.7 fathoms, and taking a mean between 
this number and that formerly found 133771.1 fathoms, we 
have for the mean diftance of Dunkirk from the Obfervatory 
133768.4 fathoms, from which fubtracting 358.6 fathoms, 
the mean fouthing of M from Dunkirk, there will ultimately 
remain 1 33409.8 fathoms for the diftance between M and the 
Royal Obfervatory at Paris, meafured on the meridian. 
Now, fince in the XLth triangle we have the diftance of 
N.D. at Calais from Dunkirk 123734.8 feet, if from this num- 
ber we fubtradl 1553.56 fathoms = 9321.36 feet, there will 
remain 1144 13.4 for the diftance of the point M from Calais. 
Thus, with the fupplemental angle to 360° at Calais, viz. 
139° 17' 3 3" -2, contained within its now known fides, 
we are finally enabled to complete the XLVth triangle, and 
thereby to determine the fituation of M with regard to Dover, 
XLV. 
f N.D. at Calais 
\ Dover Caftle 
1 M near Dunkirk 
N.D. at Calais from 
f Dover Caftle 
1 M near Dunkirk 
Dover CafUe from M 
Alfo, Dover is from Dunkirk 
139 17 33-21 The fpherical ex- 
18 24 37.3 !*cefs above i8o 0 n: 
22 *7 49-5 J 2"-42. 
Feet. 
1 37449-9 
. • 11 44 I 3'4 
236273.7 
243295,3 
Art. III. Refult of the trigonometrical operation , in as far as relates 
to the geodetical filiation of the different fattens , with regard 
to the Royal Obfervatory at Greenwich . 
Having, by the preceding calculations of the lengths of 
the fides and meafures of the angles of a continued feries of 
B b 2 forty- 
1 
