Vitry-le-François 23, 13th century, fols. 1-23, illuminated, “Incipit libellus cuiusdam ad Rainerum conversum cognomine Corde Benignum. Incipit de tribus columbis. Si dormiatis inter medios cleros ...”; it closes without Explicit, “... per bonam operationem conformem reddit.” Then follows at fol. 23v, “Incipit tractatus Hugonis de Folieto prioris canonicorum Sancti Laurentii in pago Ambianensi de claustro anime....” Vitry-le-François 63, 13th century, fol. 1-, “De tribus columbis ad Raynerum conversum cognomento Corde Benignum seu de natura avium....”; followed at fol. 7-, by portions of De claustro anime. BN 12321, 13th century, fol. 215v (where it follows works by St. Bernard), De naturis avium ad Rainerum conversum cognomine Corde benignum. Bourges 121, 13th century, fol. 128-, “Libellus cuiusdam (Hugonis de Folieto) ad fratrem Rainerum corde benignum qui Columba deargentata inscribitur.” CLM 15407, 14th century, fol. 46, Libellus qui “Columba deargentata” inscribitur, etc. CLM 18368, anno 1385, fol. 121, Hugonis de S. Victore Columba deargentata; fol. 124, Eiusdem avicularius. CHAPTER XXXVI ADELARD OF BATH Place in medieval learning--Some dates in his career--Mathematical treatises--Adelard and alchemy--Importance of the _Natural Questions_--Occasion of writing--Arabic versus Gallic learning--“Modern discoveries”--Medieval work wrongly credited to Greek and Arab--Illustrated from the history of alchemy--Science and religion--Reason versus authority--Need of the telescope and microscope already felt--Some quaint speculative science--Warfare, science, and religion--Specimens of medieval scientific curiosity--Theory of sound--Theory of vision--Deductive reasoning from hot and cold, moist and dry--Refinement of the four elements hypothesis--Animal intelligence doubted--The earth’s shape and center of gravity--Indestructibility of matter--Also stated by Hugh of St. Victor--Roger Bacon’s continuity of universal nature--Previously stated by Adelard--Experiment and magic--Adelard and Hero of Alexandria--Attitude to the stars: _De eodem et diverso_--Attitude to the stars: _Questiones naturales_--Astrology in an anonymous work, perhaps by Athelardus--Authorities concerning spirits--Adelard’s future influence--Appendix I. The problem of dating the _De eodem et diverso_ and _Questiones naturales_ and of their relations to each other--Difficulty of the problem--Before what queen did Adelard play the _cithara_?--Circumstances under which the _De eodem et diverso_ was written--Different situation depicted in the _Natural Questions_--Some apparent indications that the _De eodem et diverso_ was written after the _Natural Questions_--How long had Henry I been reigning? “_Quare, si quid amplius a me audire desideras, rationem refer et recipe._” --_Questiones naturales, cap. 6._ [Sidenote: Place in medieval learning.]