ILLUSTRATIVE MATERIAL 37 



is not always the case. There are now procurable color 

 charts of birds, butterflies, mammals, plants, and many books 

 illustrated by the three-color process which are excellent. 

 Every school ought to have them in its library. There are 

 also large printed wall charts of plants and animals, which 

 are useful in the lower grades. Some of these are published 

 by the primary education journals. 



Pictures often add a great deal even where the actual ob- 

 ject or parts of. it are present. Thus, a lesson on the pine 

 tree, though well illustrated with twigs and needles, cones, 

 cross, and longitudinal sections of the stem, bark, etc., is im- 

 proved and made more interesting by introducing pictures 

 of a pine forest, a pine tree with a man near it, for comparison 

 of height, a logging scene, a saw-mill, etc. Pictures may 

 show new features of the object or its natural surroundings. 



DIAGRAMS: Lecturers frequently illustrate their remarks 

 by crayon sketches while they talk. Such lectures are some- 

 times called "chalk talks" and are generally very popular. 

 The teacher should talk with her crayon if she has the least 

 ability to draw. Frequently she can talk to better effect 

 with her crayon than with words. Board drawings simplify 

 explanations which, without them, would be long and labored. 

 Sometimes the word-description calls up in the minds of 

 pupils an erroneous image, or none at all, while the idea 

 could have been conveyed more clearly and correctly by a 

 black-board sketch. For example, if the teacher should at- 

 tempt to describe to pupils not familiar with it the construc- 

 tion and operation of the common lifting pump by saying: 

 "In the common water pump there is a barrel or cylinder 

 within about thirty feet of the water; in this cylinder there 

 is a piston which is moved up and down by the piston rod 



