Arts, sciences and other scholarly endeavors flourished under the reign of the Abbasid caliph Al-Mahdi (r. 775-785). Al-Mahdi was apparently caught up, at times, in his era’s culture of intellectual curiosity. One supposed instance of this occurred when the caliph was staying in the city of Rayy at a time when the region was experiencing a particularly cold season. While shivering in the chilly air, Al-Mahdi apparently was suddenly struck with the inspiration to experiment with different furs, hoping to determine which of the selection was the warmest and most moisture-resistant pelt.
Al-Mahdi was not short on fur to test—he had on hand pelts of different colors from various species. To test the insulating powers of these furs, the caliph reportedly ordered that numerous flagons of water be brought forth, one for each fur that Al-Mahdi wished to test. He then reportedly stoppered and swaddled each flagon of water with a different fur and exposed the pelt-covered containers to the freezing-cold air for an entire brisk night. Come morning, the furry flagons were retrieved and the curious caliph inspected the state of the water inside each container. As the story goes, only one flagon (bundled in a black fox pelt) had survived the cold in a liquid state, whereas the water in every other container was frozen solid by morning. With this data, the experiment was concluded and Al-Mahdi proclaimed that black fox fur was the warmest fur he had on hand.
Written by C. Keith Hansley
Picture Attribution: (Illustration from the history of Muhammad Bal’ami (d. 974), [Public Domain] via Creative Commons).
- Book of Notification and Revision by Mas’ūdī (d. 957) in Ibn Fadlan and the Land of Darkness: Arab Travellers in the Far North, translated and edited by Paul Lunde and Caroline Stone. New York, Penguin Classics, 2012.