If we should designate the logical memory capacity of one person by 10, and that of another by 15, by practice we might bring the first up to 15 and the second to 22½, but we could not equalize them. We could never make the memory of the one equal to that of the other. In an extreme case, we might find one child whose experience had been such that his logical memory was working up to the limit of its capacity, while the other had had little practice in logical memory and was therefore far below his real capacity. In such a case, a test would not show the native difference, it would show only the present difference in functioning capacity. Fairly adequate tests for the most important mental functions have been worked out. A series of group tests with directions and norms follow. The members of the class can use these tests in studying the individual differences in other people. The teacher will find other tests in the author's _Examination of School Children_, and in Whipple's _Manual of Mental and Physical Tests_. =MENTAL TESTS= GENERAL DIRECTIONS The results of the mental tests in the school will be worse than useless unless the tests are given with the greatest care and scientific precision. Every test should be most carefully explained to the children so that they will know _exactly_ what they are to do. The matter must be so presented to them that they will put forth _all possible_ effort. They must take the tests seriously. Great care must be taken to see that there is no cheating. The work of each child should be his own work. In those tests in which time is an important element, the time must be _carefully kept_, with a stop watch if one is available. The papers should be distributed for the tests and turned face downward on the pupil's desk. The pupil, when all are ready to begin, should take the paper in his hand and at the signal "begin" turn it over and begin work, and when the signal "stop" is given, should quit work instantly and turn the paper over. Before the work begins, the necessary information should be placed on each paper. This information should be the pupil's name, age, grade, sex, and school. This should be on every paper. When the test is over the papers should be immediately collected. LOGICAL MEMORY =Object.= The purpose of this test is to determine the pupil's facility in remembering and reproducing ideas. A pupil's standing in the test may serve as an indication of his ability to remember the subject matter of the school studies. [Illustration: FIGURE VII--LOGICAL MEMORY "WILLIE JONES"]