“There is a birch-rod kept behind the looking-glass in the schoolroom, and every now and then it is brought out and used, for no reason that really matters. This generally happens when there is a yellow wind. . . . Most people in North China suffer from nerves during the winter months, when the air is so dry that one gets an electric shock every time that one touches metal, or takes off ones furs. The nervous tension becomes greater before a dust storm, known locally as a 'yellow wind.”