Derived from the Arabic root "kimia", from the Coptic "khem" (referring to the fertile black soil of the Nile delta), the word "alchemy" alludes to the dark mystery of the primordial or First Matter (the Khem). The discovery of this elusive original matter, from which all others are deemed simply polluted variants (the purist being Gold), is considered the alchemist's central goal — along with the discovery of the Stone of Knowledge (The Philosophers' Stone) and the key to Eternal Youth. As you can imagine, not the simplest of day jobs. As well as reams of text, the ins and outs of the alchemist's task, steeped as it is in a dizzyingly complex symbology, has given birth to a whole host of strange and wondrous imagery over the centuries. Here we pick out some favourites, many found on Wellcome Images and the brilliant Manly Palmer Hall collection at the Internet Archive.