product of most of our high school science laboratories.

After a good deal of experimenting with children in a number of science classes, the method followed in this book was developed. Briefly, it is as follows:

At the head of each section are several of the questions which, in part, prompted the writing of the section. The purpose of these is to let the children know definitely what their goal is when they begin a section. The fact that the questions had their origin in the minds of children gives reasonable assurance that they will to some extent appeal to children. These questions in effect state the problems which the section helps to solve.

Following the questions are some introductory paragraphs for arousing interest in the problem at hand,—for motivating the child further. These paragraphs are frequently a narrative description containing a good many dramatic elements, and are written in conversational style. The purpose is to awaken the child's imagination and to make clear the intimate part which the principle under consideration plays in his own life. When a principle is universal, like gravity, it is best brought out by imagining what would happen if it ceased to exist. If a principle is particular to certain substances, like elasticity, it sometimes can be brought out vividly by imagining what would happen if it were universal. Contrast is essential to consciousness. To contrast a condition that is very common with an imagined condition that is different brings the former into vivid consciousness. Incidentally, it arouses real interest. The story-like introduction to many sections is not a sugar coating to make the child swallow a bitter pill. It is a psychologically sound method of bringing out the essential and dramatic features of a principle which is in itself interesting, once the child has grasped it.

Another means for motivating the work in certain cases consists in first doing a dramatic experiment that will arouse the pupil's interest and curiosity. Still another consists in merely calling the child's attention to the practical value of the principle.

Following these various means for getting the pupil's interest, there are usually some experiments designed to help him solve his problem. The experiments are made as simple and interesting as possible. They usually require very inexpensive apparatus and are chosen or invented both for their interest value and their content value.

With an explanation of the experiments and the questions that arise, a principle is made clear. Then the pupil is given an opportunity to apply the principle in making intelligible some common fact, if the principle has only intelligence value; or he is asked to apply the principle to the solution of a practical problem where the principle also has utility value.

The "inference exercises" which follow each section after the first two consist of statements of well-known facts explainable in terms of some of the principles which precede them. They involve a constant review of the work which has gone before, a review which nevertheless is new work—they review the principles by giving them new applications. Furthermore, they give the pupil very definite training in explaining the common things around him.

For four years a mimeographed edition of this book has been used in the elementary department of the San Francisco State Normal School. During that time various normal students have tried it in public school classes in and around San Francisco and Oakland, and it has recently been used in Winnetka, Illinois. It has been twice revised throughout in response to needs shown by this use.

The book has proved itself adaptable to either an individual system of instruction or the usual class methods.

TO THE TEACHER

Do not test the children on the narrative description which introduces most sections, nor require them to recite on it. It is there merely to arouse their interest, and that is likely to be checked if they think it is a lesson to be learned. It is not at all necessary for them to know everything in the introductory parts of each section. If the children are interested, they will remember what is valuable to them; if they are not, do not prolong the agony. The questions which accompany and follow the experiments, the applications or required explanations at the ends of the sections, and the extensive inference exercises, form an ample test of the child's grasp of the principles under discussion.

It is not necessary to have the children write up their experiments. The experiments are a means to an end. The end is the application of the principles to everyday facts. If the children can make these applications, it does not matter how much of the actual experiments they remember.

If possible, the experiments should be done by the pupils individually or in couples, in a school laboratory. Where this cannot be done, almost all the experiments can be demonstrated from the teacher's desk if electricity, water, and gas are to be had. Alcohol lamps can be substituted for gas, but they are less satisfactory.

It is a good plan to have pupils report additional exemplifications of each principle from their home or play life, and in a quick oral review to let the rest of the class name the principles back of each example.

This course is so arranged that it can be used according to the regular class system of instruction, or according to the individual system where each child does his own work at his natural rate of progress. The children can carry on the work with almost no assistance from the teacher, if provision is made for their doing the experiments themselves and for their writing the answers to the inference exercises. When the individual system is used, the children may write the inference exercises, or they may use them as a basis for study and recite only a few to the teacher by way of test. In the elementary department of the San Francisco State Normal School, where the individual system is used, the latter method is in operation. The teacher has a card for each pupil, each card containing a mimeographed list of the principles, with a blank after each. Whenever a pupil correctly explains an example, a figure 1 is placed in the blank following that principle; when he misapplies a principle, or fails to apply it, an x is placed after it. When there are four successive 1's after any principle, the teacher no longer includes that principle in testing that child. In this way the number of inference exercises on which she hears any one individual recite is greatly reduced. This plan would probably have to be altered in order to adapt it to particular conditions.

The Socratic method can be employed to great advantage in handling difficult inferences. The children discuss in class the principle under which an inference comes, and the teacher guides the discussion, when necessary, by skillfully placed questions designed to bring the essential problems into relief.¹

Footnote 1: At the California State Normal School in San Francisco, this course in general science is usually preceded by one in "introductory science."

The chapters and sections in this book are not of even length. In order to preserve the unity of subject matter, it was felt desirable to divide the book according to