delivered the opinion of the court.
*1452. Mines and minerals, § 156*—when admission of evidence as to custom of miners in operation of cars is erroneous. In an action by a coal miner for injuries sustained by being struck by an empty car running down an incline in the coal mine, held that the admission of evidence concerning the habit of one of the miners to permit cars to run down the incline by force of gravity was erroneous.