The second Volume gives the Commentaries on the eight books of Aristotle's 'Physics,' and the third Volume contains those on the treatises, 'De Cœlo et Mundo,' 'De Generatione et Corruptione,' and the 'Meteorologia.'
It is worthy of note that up to the time when the new edition was undertaken, the Commentary on both of the books, 'De Generatione et Corruptione,' was looked upon as genuine work of St. Thomas; but by means of the manuscripts, as well as from internal evidence and discovery of their origin and source, it has been proved in the Preface to the third Volume, that only the first seventeen lessons of the Commentary on the First Book are by St. Thomas, the remainder on the First Book, and all on the Second, being drawn from Albertus Magnus.
Discoveries were also made concerning the Commentary on the books of the 'Meteorologia,' as may be seen in the Preface. That on the Third and Fourth were known to be spurious. That on the Third Book is taken from Peter of Alvernia; that in the Leonine Edition, the Commentary on the last lesson of the Second Book, is also shown to be taken from Albertus Magnus.
On the publication of the third Volume, the Pope addressed a Letter to Cardinals Simeoni and Zigliara (Cardinal de Luca had died), dated October ii, 1886, expressing his wish that the 'Summa Theologica' and 'Summa Contra Gentes' should be the next edited and published.
Of the former, up to this time (1906) nine volumes have been published, containing almost all that St. Thomas wrote before his death. With these appears the Commentary of Cajetan. The text of St. Thomas has been compared with manuscripts and early editions; quotations have been verified. Each manuscript used in the edition has been read through, and when it differs from the Piana, a note is made of the variant. In composing the second Volume no less than 20,000 variants were marked.
The print ng of the work was done at the Propaganda Press. The work was confided wholly to the Dominican Order by Pope Leo XIII. before his death.
