For the physics classes, the lighting, heating, and ventilating systems of the school afford a practical textbook. In the Jefferson School, where the industrial shop is built around the boiler-room, the heating plant becomes an integral part of the shop. The physics classes study the climate and the weather. They study particularly the principles of the machines used in the different shops. Each shop may thus act as an extension of the physics laboratory. Classes of even the smaller children are sent to take apart machines like the bicycle, cream-separator, lawn-mower, and explain the construction. The automobile and motor-cycle provide many practical lessons. An old automobile which needs tinkering up is considered in the Gary school to be almost a physics laboratory in itself. The writer witnessed a physics class of twelve-year-old girls who, with their nine-year-old “helpers,” were studying the motor-cycle. With that disregard for boundaries which characterizes all Gary education, the hour began with a spelling-lesson. The names of the parts and processes of the machine were rehearsed orally and then written. After the words were learned, the parts of the machine were explained by the instructor while the class spelled the words over again. Their memory of certain physical principles, such as vaporization, evaporation, were called again into play. Then the instructor set the motor-cycle going, the girls again describing its action. When this had been thoroughly gone over, the class copied from the blackboard sentences describing the processes and parts, but omitting certain crucial words which the pupil had to supply. The intense vivacity and interest of the little group, the intelligence with which these small children grasped the principles involved, made the lesson seem a model of expert teaching. It was an excellent illustration of the way concrete processes may be used to build up scientific knowledge. It is interesting to notice that no distinction is made between boys and girls in their science work. This lively interest in scientific processes may have unexpected results. The story is told of a high-school boy who, while the board of education was discussing means of fire-prevention, made an investigation of methods and processes which was so excellent that it was forthwith adopted by the board.