C 70 3 
u of by divers, as namely by Martin Cortefe, Petrus 
“ Nonius, and even Gerardus Mercator feemeth to 
“ have corrected them, in his Univerfal Map of the 
“ World ; yet none of them had taught any certain 
“ way how to amend fuch grofs faults And, in 
his. Preface, he declares, “ that, by occafion of Mer- 
“ cator’s map, he firft thought of correffing l'o many 
“ and great ablurdities in the common Sea Chart, but 
“ the way how this was by him done, he neither 
“. learnt of Mercator, nor of any man elfe.” 
Wright’s method (erroneoufly called Mercator’s) 
was at this time then adopted, has continued ever 
lince in ufe, and has been improved by fome of the 
.greateft mathematicians who have flourilhed lince 
. that time, and although fometimes attacked, yet it has 
been found impregnable. 
The frit perfon (that I am aware of) who charged 
Mr. Wright with errors in his tables of rhumbs, is 
Simon Stevins, in his large volume of mathematical 
remembrances, which Wright himfelf plainly con- 
futes in a fubfequent edition of his book : now, Ste- 
vins does not condemn the principles, but onlyalferts 
that his tables have fome faults in them, and endeavours 
to prove that the fourth rhumb at 78 deg. of longitude 
ought to have 6i d . 26™. of latitude, whereas Wright 
makes it only 6i d . i4 m . Hence, the great difference 
is no more than 12 minutes; and what inconvenience 
can arife hereby to the mariner in fuch a run, was this 
the fadt ? But it turns out otherwife, for this difference 
is reduced to lefs than one minute (even according 
to Stevins own way) as evidently appears from Wright’s 
anfwer in page 214. 
If 
