The upper marginal illustration shows a retort resting in a brick furnace, while the lower one shows a rather complex brick furnace. From a copy of Sharh Shudhur al-dhahab, a commentary by Abu al-Qasim Muhammad ibn 'Abd Allah al-Ansari on an alchemical-allegorical set of poems by his teacher Ibn Arfa' Ra's (died 1197). The copy was completed in Jumada I 1123 (March-April 1712) by the copyist Muhammad Sadiq ibn Mustafa al-Antaki al-Istanbuli al-Hanafi. A retort is a glassware device used for distillation or dry distillation of substances. It consists of a spherical, airtight vessel with a long downward-pointing neck.