of the "Trigonometrical Operation . 609 
0 4° 5*' 3 *9 ~ I9 // -42) = I4° 5 q/ 44 /, -5 = rMC, which added 
to 90° (rMg*) gives io+° 50' 44 ^5 for the angle ^MC ; from 
this take i° 48'' 3 8 7/ .6 (PMg-), and we have 105° 2 / 5^.9 for 
the angle PM^ deduced according to this method. But it can- 
not be faid to reiult from the Britifh obfervations, becaufe the 
French angles were made ufe of to the eaftward of Dover for 
obtaining the angle RMC, on which it depends. 
P. 227. The lengths of the degrees of longitude in the 
Table were found thus: as radius : cofine of the latitude :: 
length of a degree of a great circle perpendicular to the meri- 
dian : length of a degree of longitude. This proportion is 
true on a fphere, but not accurately fo on a fpheroid. 
P . 229. for 43 0 39' put 48° 39', the latitude of St. Malo. 
As the new longitudes in this Table have not all been obtained 
in the fame manner, it may not be improper to give the me- 
thods of computation. 
The latitude of Stralbourg ( Defcrip . Geom.) is 48° 34' 50", 
and its diftance from the meridian of Paris 204779 toifes 
( = 218243.17 fathoms) which, if we take 61225 fathoms = i° 
(fee the Table, p. 227.) gives 3 0 52 /7 .6; hence, as cofine 
48° 34' 5 q// : ra( J* :: fine 3 0 33' 52 /; .6 : fine 5 0 23' 33" the 
longitude. / f 
In the ConnoiJJance des Temps 1788, the latitude of Stras- 
bourg is 48° 34" 35 // , longitude 5" 26' i8 /7 ; therefore, as 
rad. : cofine 48° 3f fine 5 0 26' 18" : fine f 35' 42^.3, 
the arc of the great circle (from which its longitude was com- 
puted) pafiing through Stralbourg, and falling perpendicular 
on the meridian of Paris. 
According to the Advertifement in the Map of France, the 
French computations have been made with a degree containing 
57060 toifes ( = 60811,7 fathoms); therefore, if we reduce 
Vo l. LXXX. 4 K 2° 
