Footnote 6
Part I, §4.  See fig. 1; Chaucer describes the `bak-half' of the instrument first.  The centre of the `large hole amydde' is the centre of the instrument, where a smaller hole is pierced completely through.  The Southe lyne (marked Meridies in figs. 1 and 2) is also called Linea Meridiei, the North lyne is also named Linea Mediæ Noctis.