EMPLOYMENT PSYCHOLOGY 56 consists of taking small parts, placing them in the proper position, and then either hammering, screwing, pushing, or springing them together. The successful assembler is therefore one who is possessed, to begin with, of unusual manual dexterity. A clumsy fingered person loses a dis astrous amount of time at this work, for any natural awkwardness has hundreds of opportunities to repeat itself in the course of a day. In order to detect the presence or absence of the necessary ability, the so- called manual dexterity tests were devised. They consist of a form board with a row of pieces of graduated size cut out and the pieces left fitting loosely. In giving the test, the pieces are turned into the cover of the board and left in their exact order, after which the subject is asked to put them back into their proper spaces as expeditiously as possible. This is tried first with the right, then with the left, then with both hands. The pieces are in some cases quite large, in others quite small, just as in assembling, certain operations consist of putting together very minute and delicate parts, while others have to do with larger parts. In every case, the pieces were graduated in size and the subject was always required to work from the largest to the smallest. This served the useful purpose of increasing the difficulty of the test by degrees, thereby making it unnecessary to upset the subject by starting him suddenly at a difficult and novel task. Another quality required by the successful assembler is the ability to pick up a part, size it up, and then decide just where it belongs and how it shall be placed there. In some cases it is the ability to size up a space and then pick up the proper piece for that space. In many cases, a very fine discrimination of shapes and spaces is required