12. (Of the Two) Matters, (the Sensible and Intelligible). ii. 4. 13. Various Considerations, iii. 9. 14. Of the (Circular) Motion of the Heavens. ii. 2. 15. Of the Daemon Allotted to Us, iii. 4. 16. Of (Reasonable) Suicide, i. 9. 17. Of Quality, ii. 6. 18. Are there Ideas of Individuals? v. 7. 19. Of Virtues. i. 2. 20. Of Dialectics. i. 3. 21. (How does the Soul keep the Mean between Indivisible Nature and Divisible Nature?) iv. 2. These twenty-one books were already written when I visited Plotinos; he was then in the fifty-ninth year of his age. V. HOW PORPHYRY CAME TO PLOTINOS FOR THE SECOND TIME (A. D. 263-269). I remained with him this year, and the five following ones. I had already visited Rome ten years previously; but at that time Plotinos spent his summers in vacation, and contented himself with instructing his visitors orally. During the above-mentioned six years, as several questions had been cleared up in the lectures of Plotinos, and at the urgent request of Amelius and myself that he write them down, he wrote two books to prove that PLOTINOS'S BOOKS OF THE SECOND PERIOD (THE PORPHYRIAN PERIOD). 22. The One and Identical Existence is Everywhere Entire, I, vi. 4. 23. Second Part Thereof. vi. 5. Then he wrote the book entitled: 24. The Superessential Transcendent Principle Does Not Think. Which is the First Thinking Principle? And Which is the Second? v. 6. He also wrote the following books: 25. Of Potentiality and Actualization. ii. 5. 26. Of the Impassibility of Incorporeal Entities. iii. 6. 27. Of the Soul, First Part. iv. 3. 28. Of the Soul, Second Part. iv. 4. 29. (Of the Soul, Third; or, How do We See?) iv. 5. 30. Of Contemplation. iii. 8. 31. Of Intelligible Beauty. v. 8. 32. The Intelligible Entities are not Outside of Intelligence. Of Intelligence and of Soul. v. 5. 33. Against the Gnostics. ii. 9. 34. Of Numbers. vi. 6. 35. Why do Distant Objects Seem Small? ii. 8. 36. Does Happiness (Consist in Duration?) i. 5. 37. Of the Mixture with Total Penetration. ii. 7. 38. Of the Multitude of Ideas; Of the Good. vi. 7. 39. Of the Will. vi. 8. 40. (Of the World). ii. 1.