Designing by the square foot is, however, a good preparation, and many a good brain has been developed by such work.

The importance of designing a machine to meet all the conditions necessary to success from a mechanical and business standpoint is fully recognized by every one.  But the grouping of the ideas in the mind while working out the various phases must not be hampered by the bewildering picture of all of these problems, each demanding consideration at every move.  The phase in hand must have the concentrated attention, and the best conditions for its solution.

The harmonizing is an after-process which must be worked out by a series of compromises after the various component elements have been almost independently considered.

Problems to Consider.

In taking up the problems of design of a machine, there will be found an almost endless number of elements to consider.  The strictly mechanical problem of the best machine for the purpose never stands alone.

What is the measure of the best machine?  How much can be spent on its design and construction?  How much work is to be done?  An endless variety of questions at once crowd into the mind for answer.

It is doubtful if all the elements could ever be tabulated in any form that would be a positive guide in shaping the final result, but in a general way the designer should make a fairly good guess at the kind of standard toward which he should work.

There are, doubtless, men capable of carefully weighing the almost infinite number of variants, but such men usually lack the intuitive scheme of work, on which the inventive side of a designer depends.

For the ordinary mortal the best process of working is to keep a vague picture of the whole requirement in mind while concentrating on some one phase.

When the inventive qualities are to be called into use, the economic side, the business side, the manufacturing, the selling, the personal profit in cash or glory, all these must be absolutely crowded out of the center of the mental picture.  Even fleeting thoughts of other elements seem to prevent the inventive functioning of the mind.

In like manner the problems of manufacturing, selling, patents, business organization, must each be given a separate consideration.  The interval between taking up the various questions should be as wide as possible.  The mind seems to require a previous notice of days or weeks or more in order to take up any one of these problems, at least, with any hope of success.

The Hero of the Eraser.

The drafting board may show that no such arrangement of parts can ever be made, that the whole scheme must be altered to make it practical.  A real hero is required for the work of juggling the elements of a drafting board.  He must have patient endurance and sufficient strength of character to use the eraser heroically, for the eraser is mightier than the pencil in the drafting-room.  There are a thousand valiant knights armed with pencils to one stalwart pusher of the eraser.