us– in the attempt to give an organic, definitive and public form to the treatment of the subject, in the partial attempts at distribution of the matter , in the directions given regarding the number of the “propositions”, “cases” or “conclusions” on each single page , in the references to previous theories , in the questions dealt with from a polemical point of view , in the characteristic use of arguments by deduction, in the corollaries of a practical nature – what the development of a “science” was for Leonardo as he understood