A promotion program is preferable to a rotating one. It is not desirable to follow rigidly a plan which provides that all students get a definite length of time on each of a number of specified subjects in rotation, though such a program is well suited to the most able men. The work should be organized so that while the most able men will get the entire course of instruction, others will omit those subjects for which they have no special aptitude, giving full time and attention to those things in which they show promise of success. In general this means a course arranged not for the average but for the best student and then administered so that only those men who show or develop ability on one job will be promoted to the next more difficult task. To illustrate: In the auto-mechanic squad only those men who have thoroughly mastered the details of the axle and wheel work will progress to engine work, and then again only those who show a good understanding of engine construction will take up further study of gas engine performance. Again only those who show special all-around ability in these things will proceed further with the study of ignition, timing and the more complicated details of operation.