TEACHING METHODS 69 on the platform of the machine was arranged a small movable stool 30 cms. high, for measuring the height when seated. Today I suggest that the machine be made with a double platform; on one side to measure the full height and on the other the height when seat- ed. In the second case, the zero is at 30 cms. level, .that is. it corresponds with the height of the seat, which is fixed. The pointers running in a groove on the vertical pole are independent of each other; they can, however, take two measurements at the same time, that is, they measure two children together. In any case the inconvenience and the loss of time involved in removing and putting back the seat and in calculating the difference on the metric scale is avoided. Having thus prepared the technique of the research, I arranged to take measurements, both standing and sitting, every month; and, in order to bring together the most exact measurements relative to development and to make the research more regular, 1 made it a rule that the height should be taken on the day on which the child completed a month of its age. To secure this, I planned a register as follows: September October Day of the month Height Height Standing Seated Standing Seated 1 2 3 4 etc.