余囚北庭,坐一土室。室广八尺,深可四寻。单扉低小,白间短窄,污下而幽暗。当此夏日,诸气萃然:雨潦四集,浮动床几,时则为水气;涂泥半朝,蒸沤历澜,时则为土气;乍晴暴热,风道四塞,时则为日气;檐阴薪爨,助长炎虐,时则为火气;仓腐寄顿,陈陈逼人,时则为米气;骈肩