s correspond
to a degree can be told, nor is it easy to determine this; so that
it will be necessary, both sides concurring, to select persons and
instruments and the place for making the test. After these men had
been ordered to proceed, instruction and advice must be given them,
which being a huge matter and outside of the present discussion, I
shall not dwell upon. If such practical experience is not acquired,
then rightly and quite reasonably the measurement or size of degrees
used by the authors of tables, or of almanacs and daily calculations of
the stars, should be accepted; and such a view seems quite conclusive
to whomever is not obstinate, since it is proved that the diversity
of the relative positions of the superior bodies proceeds from the
difference between the places of observation.

Supposing that the number of miles or leagues corresponding to each
degree were to be verified by the care and skill of the men abovesaid,
then another very long and difficult calculation would be necessary,
namely, the appointment of experienced men to measure and determine
the number of measures or degrees from one continent or province to
another. And when they shall reach the half [one hundred and eighty
degrees] counting from the line passing at the end of the three hundred
and seventy leagues, at that place they shall establish a point or mark
to show what pertains to each side. But as this manner of measuring
degrees may be difficult from east to west, although easy from north
to south, recourse must be had to certain fine and subtile methods,
of which, although everybody is well informed concerning them, I
shall not hesitate to state a few facts I have been able to acquire,
in order to give these other deputies an opportunity to explain those
facts of which I am ignorant.

[Various methods for estimating the length of a degree follow. Colon
concludes thus:]

But inasmuch as the determination of the above methods seems to
be and is difficult, each one of them must be employed, and each
one put into execution, so long as one does not conflict with the
other. Furthermore the day's run must conform to these methods,
and pilots of great experience and judgment chosen. In this way it
might be hoped to determine a division in which neither part would
suffer and great loss or inconvenience. Inasmuch as, in another form,
_rebus stantibus ut nunc_, I consider it impossible that one side can
succeed in convincing the other b