of the trigonometrical Operation. 6c 5 
than on a fphere, except the latitudes of A and B are the fame. 
The difference, however, is fo minute, that for pradtical pur- 
pofes they may be confidered as equal (as in this Sedtion and 
the corollary, p.215.), without fenfible error. In the example 
at p. 106. the difference in the fum of the horizontal angles at 
A and B on this fpheroid, and on a fphere, is a fmall fra&ion 
of a fecond ; but it requires a nice computation to difcover the 
exaft quantity. The method, however, is to compute the 
angle at B in the fame manner as that is done at A ; or by 
taking the point of obfervation in the vertical GA produced, 
168 fathoms (the difference of the verticals VVB, GA) above 
the l'urface at A, and determining the diminution in the hori- 
zontal angle by a re-computation. 
Bv purfuing a method of computation fimilar to that for the 
point A at p. 196. it is evident, that the three horizontal angles 
of any triangle on a known fpheroid may be determined. 
P. 195. bottom line, for AGH put AGK, 
P. 203. There fee ms a miftake towards the latter part of 
this page; becaufe it will be feen, that no fuch fpherical tri- 
angles have been ufed in the computations but in Art. III. 
p. 206. 
P. 20 r. 1 . 13. from bottom. This muft allude to one place 
of obfervation only ; becaufe in this operation (where the lati- 
tudes have not been obferved) a principal advantage lies in hav- 
ing one of the ftations (like Botley Hill) on, or near the meri- 
dian of Greenwich, on account of obtaining its latitude pretty 
exadt ; but the farther off the other place of obfervation is, 
the better it is for the purpofe. 
P. 207. In 1 . 14. from bottom, for ::P# put :: fine P#. 
P. 208. from 1 . 5. to the period in 1 . 12. from bottom, fhould 
run thus : 
If 
