The manuscript notes described and trascribed below are unique: they show Bacon in the very act of originating, selecting and developing materials for the natural-philosophical projects of the crucial last years of his life. Many of the notes are drafts of material later incorporated in published texts—notably the Sylva Sylvarum . Examination of the drafts indicates that the Sylva is not a hotch-potch of plagiarized scraps. Bacon took great pains, acknowledged borrowings and drew heavily on his own extensive experimental and (...) observational work. The drafts also show that much of the material was used to display the explanatory power of his ambitious speculative philosophy. Preoccupation with the speculative philosophy is also evidenced in the notes which have no counterpart in the published works. Among these notes is a passage on the size of the universe, the motion of the fixed stars and the hypothesis of the earth's diurnal rotation. In that passage Bacon struggled with threats to his unswervingly geostatic conception of the universe. (shrink)