This problem has to do with different aspects of seeing that the worker is provided with proper air. We are beginning to realize that the air problem is much more complicated than was formerly thought. Recent investigations have gone to prove that the temperature of the air is fully as important as the supply of air, and that humidity is another important element. In this day no one can feel satisfied with his solution of the air problem who has not submitted it to an expert, and installed the results of his measured investigation. In the meantime, safety lies on the side of providing more fresh air than is necessary. If there is plenty of fresh air, unless the work itself demands peculiar temperature or humidity conditions, the worker is fairly safe. The rest periods that are being installed will do much to solve the air problem, as they furnish an admirable opportunity for giving the work places a thorough ventilation, if not a complete “airing out.” This is not in the least to underestimate the importance of proper temperature and of proper humidity, as will be noted later. All measured records of outputs should include records of the temperature and the humidity. The accumulation of this data is daily bringing nearer the time when standards covering these will be available. In the meantime, give the worker plenty of fresh air _all the time_. Fire Protection. The average manager to-day realizes fully the necessity for fire protection. It is not, perhaps, so fully realized that the mere knowledge that there is adequate fire protection has a considerable effect upon the mental comfort of many of the workers. Nothing is more fatiguing than worry. When each worker in the establishment knows that in case of a fire he can leave the building with speed and perfect safety, he has absolutely no worry or distraction from the fire standpoint.