(b) Systems, explaining the why.
(c) Drawings, charts, plans, photographs, illustrating methods.
(d) Records made by the worker himself.
2. Oral, the teaching of the Functional Foremen.
3. Object-lessons:
(a) Exhibits.
(b) Working models.
(c) Demonstrations by the Teacher.
(d) Demonstrations by the worker under Supervision.
Worker a Source of These Methods. — It should be often stated that, ultimately, the elements of all methods