is the proper order; since if you wished to show the usefulness of
any plan you would be obliged again to devise new machines to prove
its utility and thus would confuse the order of the forty Books and
also the order of the diagrams; that is to say you would have to mix
up practice with theory, which would produce a confused and
incoherent work.

6.

I am not to blame for putting forward, in the course of my work on
science, any general rule derived from a previous conclusion.

7.

The Book of the science of Mechanics must precede the Book of useful
inventions.--Have your books on anatomy bound! [Footnote: 4. The
numerous notes on anatomy written on loose leaves and now in the
Royal collection at Windsor can best be classified in four Books,
corresponding to the different character and size of the paper. When
Leonardo speaks of '_li tua libri di notomia_', he probably means
the MSS. which still exist; if this hypothesis is correct the
present condition of these leaves might seem to prove that he only
carried out his purpose with one of the Books on anatomy. A borrowed
book on Anatomy is mentioned in F.O.]

8.

The order of your book must proceed on this plan: first simple
beams, then (those) supported from below, then suspended in part,
then wholly [suspended]. Then beams as supporting other weights