II. _Interpretatio Naturae._--After the survey of all that has yet been
done in the way of discovery or invention, comes the new method, by which
the mind of man is to be trained and directed in its progress towards the
renovation of science. This division is represented, though only
imperfectly, by the _Novum Organum_, particularly book ii.

III. _Historia Naturalis et Experimentalis._--The new method is valueless,
because inapplicable, unless it be supplied with materials duly collected
and presented--in fact, unless there be formed a competent natural history
of the _Phaenomena Universi_. A short introductory sketch of the requisites
of such a natural history, which, according to Bacon, is essential,
necessary, the _basis totius negotii_, is given in the tract _Parasceve_,
appended to the _Novum Organum_. The principal works intended to form
portions of the history, and either published by himself or left in
manuscript, are _Historia Ventorum_, _Historia Vitae et Mortis_, _Historia
Densi et Rari_, and the extensive collection of facts and observations
entitled _Sylva Sylvarum_.

IV. _Scala Intellectus._--It might have been supposed that the new
philosophy could now be inaugurated. Materials had been supplied, along
with a new method by which they were to be treated, and naturally the next
step would be the finished result. But for practical purposes Bacon
interposed two divisions between the preliminaries and the philosophy
itself. The first was intended to consist of types or examples of
investigations conducted by the new method, serviceable for keeping the
whole process vividly before the mind, or, as the title indicates, such
that the mind could run rapidly up and down the several steps or grades in
the process. Of this division there seems to be only one small fragment,
the _Filum Labyrinthi_, consisting of but two or three pages.

V. _Prodromi_, forerunners of the new philosophy. This part, strictly
speaking, is quite extraneous to the general design. According to the
_Distributio Operis_,[48] it was to contain certain speculations of Bacon's
own, not formed by the new method, but by the unassisted use of his
understanding. These, therefore, form temporary or uncertain anticipations
of the new philosophy. There is extant a short preface to this division of
the work, and according to Spedding some of the miscellaneous treatises,
such as _De Principiis_, _De Fluxu et Refluxu_, _Cogitationes de Natura
Rerum_, m