'Some of the experiments chosen required weeks of preparation; there was apparatus to be made and fitted up, information to be sought and absorbed, so that on the final day an intelligent account could be given to any visitor watching the experiment. This work was all done out of school hours. Four or five days before Speech Day, ordinary school lessons ceased for those taking part in the conversazione; the laboratories, class-rooms, and workshops were portioned out so that each boy knew exactly where he was to work, and how much space he had. The setting up of the experiments began. To any one visiting the school on these particular days it must have seemed in a state of utter confusion, boys wandering about in all directions apparently under no supervision, and often to all appearances with no purpose. A party might be met with a jam-jar and fishing-net near the river; others might be found miles away on bicycles, going to a place where some particular flower might be found. Three or four boys would appear to be smashing up an engine and scattering its parts in all directions, while others could be seen wheeling a barrow-load of bricks or trying to mix a hod of mortar. Gradually a certain amount of order appeared, some experiments were tried and found to work satisfactorily, others failed, and investigation into the cause of failure had to be carried out. As the final day approached excitement increased, frantic telegrams were sent to know, for example, if the liquid air had been despatched, frequent visits to the railway-station were made in the hopes of finding some parcel had arrived; sometimes it was even necessary to motor to Peterborough to pick up material which otherwise would arrive too late. A programme giving a short description of the experiment or exhibit had to pass through the printer's hands. At last everything would be ready; occasionally, but very seldom, an experiment had to be abandoned or another substituted at the last moment.' The year 1905 marked a phase in the co-operative system of work on the mechanical side with the machining and erection of a six-horse-power reversing engine, designed for a marine engine of 3500 horse-power. Castings and drawings were supplied by the North Eastern Marine Engineering Works. The engine was a triumphant success, and thereafter a number of engines has been built by groups of boys. Concurrently with this steady replacement of the instructional-exercise system by the group-activity system, the mathematical work became less and less a series of exercises in style and more and more an attack upon problems needing solution in the workshops and laboratories, with the solution as the real incentive to the work. These dips into practical application gave a great stimulus to the formal mathematical teaching, for the boys realised as they could never have done otherwise the value of such work as a 'tool-sharpening' exercise of ultimately real value. § 2