A Demonstration of Nature

A Demonstration of Nature is an alchemical work attributed to John A Mehung, likely the French poet Jean de Meun (1240 - 1305).
A highly influential text, it was originally translated into English by the alchemist William Backhouse, adoptive father to the famous scholar Elias Ashmole who was undoubtedly influenced by the teachings within.
The work also found publication in the German alchemical collection the Musaeum Hermeticum, later edited and published by the English occultist Arthur E. Waite and is a must-read for any scholar of alchemy.
Jones has included a foreword introducing the text and diligently footnoted the work to give meaning and context to the original writing.
If you want to access and understand the original alchemical text, then look no further.