activity should take vacations, and how these should be spent; what are the effects upon one's working capacity from the use of liquor and tobacco in both small and large quantities; etc. All these are economic questions of great importance; and they need to be given proper attention by every engineer who aspires to efficiency in both himself and his employees.

Again, the development of the faculty of concentration is an economic consideration of the greatest value.

Labor

The scientific handling of labor is an economic problem of the utmost importance, and a treatise could well be written on the subject. The principal desideratum is to keep the workmen well, happy, and contented; and the best ways to do this are to treat them kindly, make them comfortable, feed and house them well, amuse them in their spare time, avoid working them too long hours, pay them by piece-work when practicable, listen patiently to their complaints, right their wrongs, see that they are well taken care of when they are ill or injured, and evolve, if possible, some feasible method of sharing profits with them. On the other hand, though, drive them hard and continuously during working hours, insist upon their putting in overtime when the conditions truly require it, discharge instantly all insubordinate or otherwise troublesome men, dispense quietly with the services of all shirkers, and insist that everybody put forth his best and most intelligent effort to effect the maximum of accomplishment in the minimum of time.