The important factors of any vocation may be classified very broadly under three heads, namely, nature, position, and requirements. Chart I gives a classification of work, with a few suggestive subdivisions, under each of these three general heads. The meanings of the subdivisions listed under "Nature" and "Position" are clear. CHART I /Physical |Mental |Combination of Physical and Mental |Professional /Nature..........|Commercial | |Industrial | |Fine | |Coarse | |Light | \Heavy, etc. | Work....| /Executive |Position........|Subordinate | \Staff | | /Physical | |Moral | |Intellectual \Requirements....|Emotional |Volitional |Aptitudes |Experience \Training, etc. PHYSICAL REQUIREMENTS Work has its physical requirements as to size, build, strength, endurance, freedom from tendencies to disease, agility, and inherent capacity for manual and digital skill. It may also have certain requirements as to eyesight, hearing, reaction time, muscular co-ordination, sense of touch, and even, in some particular places, sense of smell and sense of taste. Moral requirements may vary from those of a hired gunman to those of a Y.M.C.A. secretary or a bank cashier. INTELLECTUAL REQUIREMENTS Intellectual requirements and requirements in aptitudes, experience, and training vary, of course, with every kind of work, and almost with every particular job. One most valuable division of people intellectually is as to capacity of intellect. Some people have fine intellects, capable of great accomplishments in the way of education and training. They are particularly fitted for intellectual work; they have mental grasp; they comprehend; they reason; they have good judgment; they learn easily; they remember well. In every way their intellects are active, energetic, capable. Other people have only moderate intellectual capacity. They express themselves best in physical activity or in the direct, man-to-man handling of others. Their few intellectual activities may be exceedingly keen and accurate--or slow, dull, and vague. People with small intellectual capacity sometimes have remarkable vigor and clearness of mind in some one direction--such as finance, promotion, commerce; judgment of people, horses, cattle, or other living beings; mechanics, invention, music, art, poetry, or some other narrow specialty. Some intellects, in other words, are simply incompetent--others, merely narrow.