The work of Trabue in standardizing the "completion test" so that individuals may be quantitatively compared on the basis of it may serve as an example of the second form of scale. This particular test consists in requiring the individual to supply meaningful words or phrases in the blank spaces formed by mutilating logical text. It is similar to the simple exercise sometimes found in elementary text books of grammar and spelling. It seems that the ability to supply the missing words or phrases quickly in such mutilated material calls for the exercise of a type of ability which correlates to a high degree with most other measures of intelligence. Individual differences as shown by school grades, age, opinion of teachers, estimates of associates, results of other mental tests, etc., are readily and with considerable reliability revealed in the individual's ability to perform this type of test. This investigator has, after much preliminary labor, constructed a form of this test in which the material gradually increases in difficulty from beginning to end. Efficiency in the test may be measured by the point one can reach in the text in a given time. This test has been standardized, not on the basis of physical age, as in the case of the Binet-Simon scale, but on the basis of school grade, from the second grade through the high school, some four or six years beyond the point where the Binet-Simon scale ceases to be useful. A copy of this test is also given in the Appendix. Those who wish to use it should consult the original description of it, for technique, precautions, norms, and interpretation. A good example of the third form of scale is to be found in Sylvester's standardization of the "form-board" test. The "form-board" is one of the most useful tests in detecting intellectual defect that is so pronounced as to constitute the individual a "mental defective." Out of a solid base board are cut various geometrical forms, such as diamonds, stars, squares, triangular blocks, etc. These blocks are placed alongside the base from which they have been cut. The task is that of replacing all the blocks in their appropriate places, with the greatest possible speed. The test tends to reveal characteristic defects in understanding instructions, perceiving the general and specific situations, profiting by experience, recognizing form and size and other space relations, etc. The individual may work blind-folded or may use his eyes.