As a rule, ornament should never be carried further than graceful proportions; the arrangement of framing should follow as nearly as possible the lines of strain. Extraneous decoration, such as detached filagree work of iron, or painting in colours, is so repulsive to the taste of the true engineer and mechanic that it is unnecessary to speak against it.
(1.) Name some of the principal points to be kept in view in preparing designs?—(2.) Why should attempts at designing be confined to one class of machinery?—(3.) What objection exists to examining references when preparing designs?
CHAPTER XL.
INVENTION.
The relation between invention and the engineering arts, and especially between invention and machines, will warrant a short review of the matter here; or even if this reason were wanting, there is a sufficient one in the fact that one of the first aims of an engineering apprentice is to invent something; and as the purpose here is, so far as the limits will permit, to say something upon each subject in which a beginner has an interest, invention must not be passed over.
It has been the object thus far to show that machines, processes, and mechanical manipulation generally may be systematised and generalised to a greater or less extent, and that a failure to reduce mechanical manipulation and machine construction to certain rules and principles can mainly be ascribed to our want of knowledge, and not to any inherent difficulty or condition which prevents such solution. The same proposition is applicable to invention, with the difference that invention, in its true sense, may admit of generalisation more readily than machine processes.
Invention, as applied to mechanical improvements, should not mean chance discovery. Such a meaning is often, if not generally, attached to the term invention, yet it must be seen that results attained by a systematic course of reasoning or experimenting can have nothing to do with chance or even discovery. Such results partake more of the nature of demonstrations, a name peculiarly suitable for such inventions as are the result of methodical purpose.
In such sciences as rest in any degree upon physical experiment, like chemistry, to experiment without some definite object may be a proper kind of research, and may in the future, as it has in the past, lead to great and useful results; but in mechanics the case is different; the demonstration of the conservation of force, and the relation between force and heat, have supplied the last link in a chain of principles which may be said to comprehend all that we are called upon to deal with in dynamical science, and there remains but little hope of developing anything new or useful by discovery alone. The time has been, and has not yet passed away, when even the most unskilled thought their ability to invent improvements in machinery equal with that of an engineer or skilled mechanic; but this is now changed; new schemes are weighed and tested by scientific standards, in many cases as reliable as actual experiments. A veil of mystery which ignorance of the physical sciences had in former times thrown around the mechanic arts, has been cleared away; chance discovery, or mechanical superstition, if the term may be allowed, has nearly disappeared. Many modern engineers regard their improvements in machinery as the exercise of their profession only, and hesitate about asking for protective grants to secure an exclusive use of that which another person might and often does demonstrate, as often as circumstances call for such improvement. There are of course new articles of manufacture to be discovered, and many improvements in machinery which may be proper subject matter for patent rights; improvements which in all chance would not be made for the term of a patent, except by the inventor; but such cases are rare; and it is fair to assume that unless an invention is one which could not have been regularly deduced from existing data, and one that would not in all probability have been made for a long term of years by any other person than the inventor, such an invention cannot in fairness become the property of an individual without infringing the rights of others.
It is not the intention to discuss patent law, nor even to estimate what benefits have in the past, or may in the future, be gained to technical industry by the patent system, but to impress engineering apprentices with a better and more dignified appreciation of their calling than to confound it with chance invention, and thereby destroy that confidence in positive results which has in the past characterised mechanical engineering; also to caution learners against the loss of time and effort too often expended in searching after inventions.