The Da Vinci Notebooks at sacred-texts.com
The smallest natural point is larger than all mathematical points, and this is proved because the natural point has continuity, and any thing that is continuous is infinitely divisible; but the mathematical point is indivisible because it has no size.
28:26 : This definition was inserted by Leonardo on a MS. copy on parchment of the well-known "Trattato d'Architettura civile e militare" &c by FRANCESCO DI GIORGIO; opposite a passage where the author says: 'In prima he da sapere che punto è quella parie della quale he nulla--Linia he luncheza senza àpieza; &c