Sulfuric acid the Hellenistic alchemical works of Zosimos of Panopolis, in the treatise "Phisica et Mystica", and the Leyden papyrus X. Medieval Islamic era alchemists, Jābir ibn Hayyān (c. 721 – c. 815 AD, also known as Geber), Razi (865 – 925 AD), and Jamal Din al-Watwat (d. 1318, wrote the book "Mabāhij al-fikar wa-manāhij al-'ibar"), included vitriol in their mineral classification lists. Ibn Sina focused on its medical uses and different varieties of vitriol. Sulfuric acid was called "oil of vitriol" by medieval European alchemists because it was prepared by roasting "green vitriol" (iron(II) sulfate) in an iron retort. There are
Today Is Yesterday a single contender which didn't make the cut. Track 14 is the earliest recording on this album. Tracks 15 and 16 were both recorded in 1967. Track 15 became the A-side of Harper's third single, however track 16 was rejected. Track 17 goes back to 1965–1966 and is the A-side of Harper's first single. "All tracks credited to Roy Harper" Today Is Yesterday Today Is Yesterday is a 2002 compilation album by English folk/rock singer-songwriter Roy Harper. Amongst its 17 tracks are six unreleased and eight rare songs. All the tracks were recorded between 1964 and 1969. Tracks 1–9 date