British Library MS. Sloane 1806. Paper. Octavo. 52 folios. 17th Century. Bound together with MSS. Sloane 2228, 2234. 'The preciouse and profound practize of the auntient arte of Alchymie with the plaine and perfect way to make the Philosopher's Stone, shewing also the matter and makinge of Aurum Potabile. A secret of secrets disclosing the wonderfull workes of God in nature, and the hidden power that this sovereign medicine hath over all bodies animall, vegitable and minerall by certayne testimonie of demonstations infallible of diverse authors, holy divynes, lawyers, physicians, philosophers and poets gathered and selected by the famous philosopher R. Vall.' ff.2-50. A translation of the treatise of Robertus Vallensis 'de veritate et antiquitate Arts Chemicae.'