propofed trigonometrical operation. i 9 c 
with the meridian of io° 18' 25" towards the fouth-weft : and 
the angle between Broulezele and Hondfcote being 78° 1 1' 42", 
their difference 67° 53' 17" is the angle that Hondfcote is 
fouth-eaft from the meridian ; wherefore the complement of this 
laft angle to i8o°, viz. 1 12 0 6' 43" is the angle that Hondfcote 
makes with the meridian of Dunkirk produced northward. By 
p. 166. of the lecond part, Dunkirk being the ftation, the 
angle between Hondfcote and Mont-Caflel is fhewn to be 
51 0 Y 1 5" ; that between Mont-Caflel and Watten 42 0 6 ' 35"; 
and by p. 167. that between Watten and Calais is 51 0 40' 2o 7/ . 
The fum of thefe three angles is 144 0 54' 10", from which 
deducting 67° 53' l Y' the angle that Hondfcote is fouth- 
eaftward from the meridian, there remain 77° o / 53 // for the 
angle of Calais fouth- weft ward from it *, and the complement 
of this angle to 1 8o°, viz . io2°59 / 7", becomes the angle that 
the meridian of Dunkirk produced northward makes with a line 
drawn through M to Calais : to which laft adding the angle of 
convergence of one meridian to the other 1' correfponding 
to the diftance of 1514 fathoms, equal to 1' 29" l of a great cir- 
cle, we fhall have 103° o' 57" \ for the angle which the meridian 
of Paris produced northward from M makes with the line 
joining Dunkirk and Calais. 
Again, by p. 63. of the third part of M. Cassini’s book, 
Dunkirk being the ftation, the angle that Gravelines makes with 
the meridian fouth-weftward is 72 0 ii / 48 ' ; and bv p. 12. 
of the faid third part, the angle between Watten and N. D. 
Calais is 51 0 39' 50^ : alfo that between Gravelines and Calais 
is 56° 42' o". Now the difference between thefe t\Vo laft 
4° 47' 50" being added to 72 0 if 48", we fhall have 76° 59' 
38". and its complement 103° o' 22", for the angles that the 
meridian of Dunkirk makes with the line drawn from thence 
through the point M to Calais : to which laft angle adding 
Ccz the 
