Reading the 1 degree scale

Of the 50 lines of latitude given in The World Encompassed, 32 are given in degrees and minutes.

Of those containing minutes, twenty-three of contain minutes that represent fractions of a degree that can be easily estimated on a scale divided in whole degrees: 1/4=15', 1/3=20', 1/2=30', 2/3=40', 3/4=45'.

In the remaining nine cases, the minutes given in The World Encompassed seem to represent a precision that lies outside the resolution of that one degree scale. However, rather than representing false precision, these nine lines of latitude which contain minutes of arc expressed as 32', 55', 55', 5', 27', less 3-4', 6', 13', 4' suggest two possibilities:

(1) they were calculated means of a series of observations--remembering that at the resolution of these instruments there is a window of some several minutes of time preceeding and following meridian transit in which to take multiple altitudes of the single event;

(2) they were estimated when it was apparent that the index pointer did not come quite to, or was just over, a division of the scale.