In the course of his work with defectives, Binet, as we have seen, had gathered a number of questions which he had found useful as tests of intelligence. He now, in conjunction with Dr. Simon, proceeded to extend the number of these tests and to assign each to its appropriate age. The method he adopted was this: He tried each test on a great number of normal children of the same age. If a large majority answered satisfactorily, he set the test down as suitable for that age; if a majority failed, he moved it to a more advanced age, and tested it again on older children. When we consider his scale then, we must remember that the arrangement is no arbitrary one, but has been derived from actual experiment. In 1908, after having been tried on over two hundred Parisian school children, the tests were published in the form of a scale, giving a measure of intelligence graded from three to thirteen years of age. By this scale it was held a child's mental age, which, of course, was often not the same as his chronological age, could be determined. In 1911 there was published a revised scale in which, owing to the results of further experiment and criticism, a considerable number of alterations in the grading of the tests was made. This revised form of the scale is given below. For convenience in use the _exact_ words to be said to the child are placed first, the particular directions for each test being given afterwards. General directions regarding the tests and the method of marking will be found at the end of the scale. Tests of Intelligence. _Three Years._ 1. "Show me your eyes." "Show me your nose." "Show me your mouth." Count the child correct if he indicates in any way that he understands. 2. "I am going to say two numbers. Say them after me--3, 7."--"Again, 6, 4."--"Again, 0, 5." The examiner must say the figures slowly; an interval of half a second should be allowed between the two. The child passes if he is successful once out of the three trials. 3. "Here is a picture; tell me what you see." The child passes at this level if he simply enumerates objects seen in the pictures (Figs. 1, 2, 3). 4. "What is your name?" For a pass the surname must be given, but if the child says his Christian name only, the examiner may press him by asking "What else?" 5. "Say this sentence after me--'I am cold and hungry.'" If the child is timid, he may be tried first with shorter sentences. He is not allowed to pass unless his enunciation is perfect. A sentence containing six syllables should be remembered at this level. _Four Years._ 1. "Are you a little boy or a little girl?" If necessary, this question may be divided: "Are you a little boy?" "Are you a little girl?" 2. "What is this?"--"And this?"--"And this?" The examiner shows the child successively a key, a penny, and a knife. 3. "I am going to say three numbers. I want you to repeat them. Listen. 2, 7, 5."--"Again, 9, 0, 4."--"Again, 3, 8, 1." One success suffices.