Soap was exported from Syria to other parts of the Muslim world and to Europe.[46] Mental institute: In 872, Ahmad ibn Tulun built a hospital in Cairo that provided care to the insane, which included music therapy.[47] Kerosene: The process of distilling crude oil/petroleum into kerosene, as well as other hydrocarbon compounds, was first written about in the 9th century by the Persian scholar Rāzi (or Rhazes).