_a._ Coming within the experience of the pupils. _b._ Being suited to their age and previous training. _c._ Possessing pertinent and attractive qualities. 2. Afford wide opportunity for independent choice. 3. Be simple and adapted to the standards of the community. 4. Be reasonable in cost. Teachers of art have a double problem in the selection of illustrative material in that they must not only choose those things which meet the above standards, but they must eliminate those in which there are unrelated factors which cause a lack of clarity. Quality rather than quantity should be the guide in making selections, for a small amount of well selected and arranged illustrative material is usually more effectively used than a large unorganized collection. Having determined upon the pieces of material that are desirable, the next problem is where to obtain them. Every teacher of art should build up her own personal collection of materials to supplement what can be procured from other sources, for one teaches best from her own material. At the same time, the teacher has a responsibility in guiding the selection of some pieces which should be provided by the school as permanent illustrative material. Still other pieces which it is inadvisable for either teacher or school to buy may be borrowed for special purposes. Chart 3 lists the general types of illustrative material and indicates possible sources of this material. Chart 3.--_Types and sources of illustrative materials_