We have had constantly before us the gradual extension of the principle of multiple service of public facilities. The Gary plan makes the public school the last of these public services to come under the operation of these principles. As generally managed the public school has not recognized these principles. The effect of its administrative methods, its rigid school hours, its uniform curriculum, its emphasis on academic work, has been rather to increase the “peak-loads” and thus inadvertently to increase the costs of operation. In many schools, the use of the “auditorium” does not average more than ten minutes a day for each day of the year, and the playgrounds barely an hour each day of the year. And for every hour that shops, etc., are empty, there is a waste and leakage, which would be permitted in no other public-service institution. The Gary plan, therefore, has worked out a multiple use of the school plant in the most comprehensive form. By distributing classes in alternating groups, so that every department and room is in use as nearly as possible every hour of the eight-hour day, the “peak-loads” are prevented and the costs of operation reduced to the minimum. This system, variously called a “rotation-of-crops” or a “platoon” system, permits almost the actual doubling of the capacity of the school plant. Two duplicate schools may function together in the same building all day long. This “duplicate-school” plan is not, it must be observed, that used in some cities, where one school occupies the rooms for a few hours while the other remains at home, to take its turn in the rooms while the other goes out. That is merely a “part-time” scheme, and only accentuates the usual evils of fragmentary schooling and demoralizing street life. The Gary plan involves two distinct schools, known as the “X” and the “Y” schools, each of which has the entire program and the full day. The Gary plan, in other words, can accommodate twice the ordinary number in a school-building, not by shortening the time for each child, but actually by lengthening it.