PROCEDURE. Place the five boxes on the table in an irregular group before the child and say: "_See the boxes. They all look alike, don't they? But they are not alike. Some of them are heavy, some are not quite so heavy, and some are still lighter. No two weigh the same. Now, I want you to find the heaviest one and place it here. Then find the one that is just a little lighter and put it here. Then put the next lighter one here, and the next lighter one here, and the lightest of all at this end_ (pointing each time at the appropriate spot). _Do you understand?_" Whatever the child answers, in order to make sure that he does understand, we repeat the instructions thus: "_Remember now, that no two weights are the same. Find the heaviest one and put it here, the next heaviest here, and lighter, lighter, until you have the very lightest here. Ready; go ahead._" It is best to follow very closely the formula here given, otherwise there is danger of stating the directions so abstractly that the subject could not comprehend them. A formula like "_I want you to arrange the blocks in a gradually decreasing series according to weight_" would be Greek to most children of 10 years. If the subject still seems at a loss to know what to do, the instructions may be again repeated. But no further help of any kind may be given. Do not tell the subject to take the blocks one at a time in the hand and try them, and do not illustrate by hefting the blocks yourself. It is a part of the test to let the subject find his own method. Give three trials, shuffling the boxes after each. Do not repeat the instructions before the second and third trials unless the subject has used an absurd procedure in the previous trial. SCORING. The test is passed if the blocks are arranged in the correct order _twice out of three trials_. Always record the order of arrangement and note the number and extent of displacement. Obviously an arrangement like 12-6-15-3-9 is very much more serious than one like 15-12-6-9-3, but we require that two trials be absolutely without error. Scoring is facilitated if the blocks are marked on the bottom so that they may be easily identified. It is then necessary to exercise some care to see that the subject does not examine the bottom of the blocks for a clue as to the correct order. REMARKS. Binet originally located this test in year IX, but in his 1911 revision changed it to year VIII. Other revisions have retained it in year IX. The correct location depends upon the weights used and upon the procedure and scoring. Kuhlmann uses weights of 3, 9, 18, 27, 36, and 45 grams, and this probably makes the test easier. Bobertag tried two sets of boxes, one set being of larger dimensions than the other. The larger gave decidedly the more errors. If we require only one success in three trials the test could be located a year or two lower in the scale, while three successes as a standard would require that it be moved upward possibly as much as two years.