His work advanced with and was modified by his investigations.
In 1620 he wrote the _Novum Organum_, which, when it first appeared, called forth from James I.the profane _bon mot_ that it was like the peace of God, "because it passeth all understanding." Thus he was preparing the component parts, and fitting them into his system, which has at length become quite intelligible.

A clear notion of what he proposed to himself and what he accomplished, may be found in the subjoined meagre sketch, only designed to indicate the outline of that system, which it will require long and patient study to master thoroughly.
THE GREAT RESTORATION, (MAGNA INSTAURATIO.)--He divided it into six parts, bearing a logical relation to each other, and arranged in the proper order of study.
I.Survey and extension of the sciences, (_De Augmentis Scientiarum_.) "Gives the substance or general description of the knowledge which mankind _at present possesses_." That is, let it be observed, not according to the received system and divisions, but according to his own.

It is a new presentation of the existent state of knowledge, comprehending "not only the things already invented and known, but also those omitted and wanted," for he says the intellectual globe, as well as the terrestrial, has its broils and deceits.
In the branch "_De Partitione Scientiarum_," he divides all human learning into _History_, which uses the memory; _Poetry_, which employs the imagination; and _Philosophy_, which requires the reason: divisions too vague and too few, and so overlapping each other as to be of little present use.

Later classifications into numerous divisions have been necessary to the progress of scientific research.
II.

Precepts for the interpretation of nature, (_Novum Organum_.) This sets forth "the doctrine of a more perfect use of the reason, and the true helps of the intellectual faculties, so as to raise and enlarge the powers of the mind." "A kind of logic, by us called," he says, "the art of interpreting nature: differing from the common logic ...