Blank recto with show-through from the verso
Mechanical drawings and notes on folio 231v are faintly visible through the leaf
The recto carries no writing or drawing of its own; only a faint, mirror-reversed offset of the lattice trusses, hoisting mast and other mechanical figures drawn on the verso (231v) shows through the sheet. The modern folio number 231 is inked in the upper right corner. The actual, legible content of this leaf lies on its verso.