A chosen subject is brought, with some lasting effect, to the center of attention by repeatedly bringing it into the mind at the moments of lull in the pressure of other affairs. The astronomers wait for the moment of best seeing, and the designer must wait for the actual psychological moment. The best seeing condition for the astronomer is due in a small measure to his own physical condition, and in a large measure to atmospheric conditions, but the most opportune time for clear-headed vision of the designer is due mostly to his own physical and mental condition. Probably no two men have their minds equally affected by their environment or their physical condition, but the fact that there is a most favorable time and condition for such thought and work should continually be borne in mind. Without this a man with natural endowment may try his wings at flight at an inopportune time, and if he fails he may be firmly convinced that he was never made for flying. This undoubtedly applies equally well to other kinds of work. It may not be strictly true of a perfectly normal man (if there be such a creature), but it is truly applicable to many workers in this and similar kinds of work. This phase is mentioned in order to make clear, not only how a designer should work, but the thought that should be kept uppermost in the mind of one who is trying to do this work. The physical condition is more or less dependent on the mood, and to a great extent the mood is dependent on the condition of the body. The strenuous gait is seldom the best, and, of course, the extremely indifferent one is of little value. The best for the average man is one born of a quiet environment, with mind and body in a fairly restful condition, or still better, in a rested and fresh condition. Concentrating Attention. The quiet end of the day is almost as good for clear thinking as the early morning, especially if the day has not been overstrenuous and the activities have been gradually tapered off. There are many instances that would seem to show that the strenuous gait is the best, but nearly all of these evidences are questionable. When finally simmered down, the good work done under high pressure is frequently due to latent ideas that were the product of quiet thinking. The mood and the dominant idea may be predicated as necessary. As already stated, the habit of thought most favorable for the persistence of a single group of ideas is attained by the practice of switching the attention back to the desired subject. This should be done at the opportune time. The subject should not be forced on a tired mind. It should not be taken in as a painful duty, but it should be made the one thing of interest. Really valuable results can only come along the line of the dominant thought. All other work lacks directness. It follows precedent to an unnecessary extent. Interest Must be Awakened, Not Forced.