““One caliph in the eighth century went so far as to conduct a series of experiments to freeze a range of different furs to see which offered the best protection in extreme conditions. He filled a series of containers with water and left them overnight in ice-cold weather, according to one Arabic writer. ‘In the morning, he had the [flasks] brought to him. All were frozen except the one with black fox fur. He thus learned which fur was the warmest and the driest.’22””