In first working out the mechanical schemes no energy should be wasted in trying to make the sketches correct in proportion. The very functioning of the brain along the draftsman's line shifts it away from the inventive mood. The exact drawing frequently shows the necessity of change in general scheme, but that is only one of the after-steps.

The fundamental idea is the starting-point, and must be sketched out as fully as possible without losing the very frail thread of thought.

A clear view of the scheme is not to be obtained on demand. The schemer must wait in patience, as the astronomer waits for steady air, and, like the astronomer, he must have every facility in shipshape. The clear view is only clear to the watching eye.

The coast-wise skipper in making a fog-bound harbor will see a buoy through a slight shift in fog, while a landsman might look in vain.

The wanderer in the happy dreamland of mechanical scheming must not be looking for complete drawings, specifications, and working model of the invention he wishes to bring into the breathless and waiting world. He must be looking through the mist of the thickened senses as the skipper looks through the fog. The buoy and the scheme may be never so faintly shown, but yet with sufficient clearness to give a positive guide for the course.

Inventive schemes cannot be forced by strenuous effort. Such effort may result in slight refinements of a given type, but never would have invented the DeLaval or Tesla turbine.

It is not my purpose to belittle the great work that has been done in improving existing machines, for this, after all, is the real great work that must be done. It is the work to which the world owes its greatest debt for progress in material wealth.

Furthermore, it is a phase that must be considered in connection with every invention before that invention can become of value to any one. But just now we must consider how the inventor must work while dreaming out the fundamental ideas of a mechanical scheme.

The clear view of a mechanical scheme is more likely to come after a good night's rest, particularly if the schemer has retired with the problem in mind. There are times when invention comes under severe stress, hard physical work, and mental anxiety, but the most usual time is after a sleep which refreshed mind and body.

After this the inventor brings his scheme to the drafting board, to patent office, to factory, and to the market, and in each case he encounters barriers.

Designing by the Square Foot.

The ordinary work of machine design, in which well-known parts are grouped to accomplish a given end, without much thought of attaining anything approaching the best,--such designing is like painting a fence, so many square feet of paper should be covered per day. But the real higher type of work cannot be measured in this way. It requires the forethought, the close application, the keen interest, and the comfortable idea building.

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.

In the drafting-room the work of harmonizing must go on; compromises must be made between the ideal scheme of the dreamer and the requirements of the manufacturing and selling departments.

Next to the n.o.ble knight of the eraser comes the idealist who has been toughened by experience in the cold world.

The idealist aims to design and construct a perfect machine. He is encouraged in his work by seeing a little clearer each day, month, and year of the time spent in the right kind of application to his work. He knows that the work of last year is faulty, that this year's work seems nearly perfect, excepting for a certain slight change that has just entered his mind. He cannot think of allowing any machine to be made without this later improvement.

He is inclined to the optimistic view, his memory works best on the good work of the past, and is extremely poor in holding afresh the view of previous mistakes.