| RefNo | RB/1/25/44 |
| Previous numbers | BP 25, pp. 423-6 |
| Level | Item |
| Title | `A Conjecture at the Causes of the real Virtues of Gems & medicinall stones' |
| Date | 1660s |
| Description | MS text overlapping with the introduction to section I of 'Gems', first part published in paragraphs 4-6, the rest discarded. \r\nHand: E, corrections by Boyle |
| Language | English |
| Extent | pp. 423-6 (2 leaves) |
| Format | Manuscript |
| AccessStatus | Open |
| RelatedMaterial | Published in 'Works', vol. 7:pp. xiv-xv; overlapping with ibid., 12-13. \r\nFor later version, see BP 38, fols. 123-4. |