THE NOVUM ORGANUM. 75 



placed in the third part of the Instauratio, as for instance a 

 fragment, published by Rawley in 1658, entitled Historia et 

 Inquisitio prima de Sono et Auditu et de Forma Soni et latente 

 processu Soni, sive Sylva Soni Auditus. But the substance of 

 this fragment occurs also in the Sylva Sylvarum, and therefore 

 it cannot have been Bacon's intention to publish both as portions 

 of his Historia Naturalis. It is probable that the Historia de 

 Sono et Auditu was originally written as a portion of the general 

 scheme of natural history 1 which was to form the third part of 

 the Instauratio ; but it is certainly superseded by the Sylva 

 Sylvarum, and is therefore not entitled to the position which 

 has generally been assigned to it. So, too, the Histories Natu- 

 ralis ad condendam Philosophiam Prcefatio destinata 2 , pub- 

 lished by Gruter, is clearly irreconcilable with the plan laid 

 down in the dedication to Prince Charles of the Historia Natu- 

 ralis. For Bacon's intention when he wrote the preface which 

 Gruter has published was plainly to commence his Natural 

 History by treating of density and rarity, and not of the natu- 

 ral history of the winds. Subsequently he changed his plan ; 

 and the first published portion of the third part of the Instau- 

 ratio is, as we have seen, the Historia Ventorum. But this 

 change of plan plainly shows that he had determined to cancel 

 the fragment preserved by Gruter. Whenever what an author 

 publishes or prepares for publication supersedes or contradicts 

 unpublished and unfinished papers, these ought beyond all ques- 

 tion to be set aside, and if published at all to be published 

 apart from his other writings. Against some of the other frag- 

 ments included in the third part of the Instauratio there is no 

 such direct evidence as there is against those of which we have 

 been speaking ; but it only gives rise to needless confusion to 

 mix up with what we know it was Bacon's intention to publish 

 as portions of his Historia Naturalis, loose fragments touching 

 which we have no information whatever. 



From what has been said it is manifest that what we possess 



1 It was probably the table De Sono referred to in the Commentarius solutus, 

 July 26. 1608 (see note 2. p. 73.), and designed, like the tables De Motu and De Ga- 

 lore, et Frigore, for an example of the new method. /. S. 



2 See Bouillet, vol. ii. p. 264. The preface in question is the introduction to the 

 Tabula Exporrectionis et Expansionis Material, a rudiment of the Historia Densi et 

 Ran. It was published by Gruter, before the Historia Densi et Rari appeared, 

 among the Impetus Philosophici ; with the title, Phenomena Universi ; sive Historia 

 Naturalis ad condendam Philosophiam. Praefatio. M. Bouillet gives the preface only, 

 The whole tract as given by Gruter will be found in Part HI. of this edition. J. S. 



