A true light of alchymy. [electronic resource] : Containing, I. A correct edition of The marrow of alchymy, being a Celebrated Experimental Treatise, discovering the Secrets and most Hidden Mystery of the Philosophers Elixir, both in Theory and Practice. II. The errors of a late tract called, A short discourse of the quintessence of philosophers, wherein is pretended to be set forth, how one Select Person might be made partaker of it by the Authors means, and others rightly Directed in prosecuting that Study. III. The method and materials pointed at, composing the sophick mercury, and Transmuting Elixir, in plain Terms, free from all Enigma's. The like never before Emitted to the World.