Mechanician

“ It is indeed astonishing to how small a depth the methods hitherto used have penetrated into their real nature, and how incompletely known therefore are most of the mechanisms in common use. To the thorough, thoughtful mechanician who looks at his work as a serious matter, a scientific investigation of the Kinematics of Machinery will in this respect be specially valuable. It will relieve him of the minute and often worrying search after solutions of his problems by rendering it possible for him to work systematically. ”

“ The faculty is undoubtedly useful in a high degree to inventive mechanicians, and the great majority of those whom I have questioned have spoken of their powers as very considerable. They invent their machines as they walk, and see them in height, breadth, and depth as real objects, and they can also see them in action. ”

“ The Yankees, the first mechanicians in the world, are engineers-- just as the Italians are musicians and the Germans metaphysicians-- by right of birth. Nothing is more natural, therefore, than to perceive them applying their audacious ingenuity to the science of gunnery. ”

“ The sciences we have been considering under the general name of mechanics, which is derived from a Greek word that means to contrive, invent, construct, have much to do with machinery, with the methods of construction, the propelling forces, and the phenomena produced. There were machinists and some simple machines propelled by human or brute force, by weights and springs, by falling or running water, and air in motion before the laws of motion and forces were understood, or the rude mechanic arts began to assume the character of a science. ”

“ They are apt to think, for instance, that the problems connected with making the parts of an engine require the especial study, one may say almost the life study, of a set of engine-making mechanics, and that these problems are entirely different from those which would be met with in machining lathe or planer parts. In fact, however, a study of those elements which are peculiar either to engine parts or to lathe parts is trifling, compared with the great study of the art, or science, of cutting metals, upon a knowledge of which rests the ability to do really fast machine-work of all kinds. ”

“ To take our illustration again from mechanics, we may say that if a man is inventing a particular machine,—a sewing machine, a reaper,—nothing is more important than that he should have a precise idea of the operation which his machine is to perform, yet when he is treating the general principles of mechanics he may discuss the lever, or the form of the teeth of wheels which will transmit uniform motion, without inquiring the purpose to which the apparatus is to be applied ”

“ Many would not call the balance which we have just mentioned a machine, in consquence of the narrowness of the limits within which, its motion is confined; but force and motion are employed in it in exactly the same way as in other machines; it certainly ought there- fore to receive the same name. We may much rather say that the Engineer's measuring instruments, the theodolite, level and so on, are not machines. Here indeed mechanisms, in exactly the above de- scribed meaning, are used, and forces must be applied to these in just the way we have supposed in order that they may be used. ”

“ This shows within what distinct limits machine-problems lie, and that they allow themselves to be readily separated from the general problems of Mechanics, as we have already maintained.
While the science of Mechanics examines motion caused in the most general cases by the action of mechanical forces, Machine-mechanics occupies itself with certain special cases only, with motions produced by a limited circle of means. It draws its first laws from the same fountain as Mechanics, to which, as the more comprehensive science, it is subordinate. ”

“ To-day popular usage is restoring to the term its original broad interpretation, and it is in this popular but rather unorthodox sense that “Mechanics” has been chosen as the title of this book; for although certain elementary principles of mechanics are described and explained, the major portion of the book deals with machines and their evolution to their present stage of perfection.
Machines are man’s creation, and yet in a sense the man of to-day is a machine product; for modern civilization owes its material and in large measure its esthetic development to machinery. ”

“ The machine tools did all the working (for the thinking had been embodied in them beforehand) , and they turned out all manner of geometrical forms with the utmost correctness. This sort of training educated the faculties of the lads, and trained their ideas to the perception of exactness of form, at the same time that it gave them an intimate acquaintance with the nature of the materials employed in mechanical structures. The rapidity with which they thus acquired the efficiency of thoroughly practical mechanics was surprising. ”

“ The perfection of modern machine-tools is such that the utmost possible precision is secured, and the mechanical engineer can calculate on a degree of exactitude that does not admit of a deviation beyond the thousandth part of an inch. ”

“ He who would accomplish most in the profession of the mechanical engineer must best combine scientific attainments—and especially experimental knowledge—with mechanical taste and ability and a good judgment refined by engineering experience. ”

“ In 1841 he published his ‘Principles of Mechanism.’ In this work he reduced the study of what he called pure mechanism to a system. It is the earliest attempt to develop, with anything like completeness, the science of machines considered from the kinematic point of view, without reference to the forces which are at work or to the energy which is transmitted. A machine, according to him, is a contrivance for producing a specific relation between the motions of one of its parts and another. ”

“ It must be admitted, too, that the sense of the reality of this separation has been felt not only by Engineers or others actually engaged in machine design, but also by those theoretical writers who have had any practical knowledge of machinery, in spite of the increasing tendency in the treatment of mechanical science to thin away machine-problems into those of pure mechanics. ”

“ Mechanics are still living who firmly believe in the possibility of realizing a mechanical perpetual motion,—to spin, pump, or drive carriages or machinery, by means of a constantly descending weight. ”

“ The study of kinematics has been considered for nearly 80 years as a necessary part of the mechanical engineer's training, as the dozens of textbooks that have been published over the years make amply clear. ”

“ The man who aspires to construct any great mechanical engineering work, like the Brooklyn Bridge, for example, must know the exact mechanical power of every piece of machinery he employs, as also the exact mechanical value of every piece of iron that enters into the structure; and these things he cannot know unless he is familiar with the entire series of iron manipulations, from those of the foundery to those of the machine-tool shop. ”

“ But another conclusion follows more irresistibly, namely—that the mechanical engineer who devotes his attention to the construction and management of massive machinery, such as pumps, hydraulic and lever presses, looms, and steam-engines, whether locomotive, marine, or other, must, in order to be master of his profession, be thoroughly familiar with every step of their construction; and such familiarity can only be acquired by a course of practical study in the machine-tool shop. ”

“ How to Experiment with Machines.—Any one who possesses the slightest bent for mechanics can work out improvements on devices like egg-beaters and monkey-wrenches and feel their way as they go along.
But when it comes to designing and building real machines where numerous levers, gears, and springs are combined to make a working unit you should by all means read up on the subjects of work, energy and power, learn about the six mechanical powers—and the action of machines in general. ”

“ MECHANICAL TRIUMPHS. The direct and almost instant benefits of Mechanical Inventions to their originators have been thus eloquently illustrated in the Edinburgh Review:—"Contributing, as they do, to our most immediate and pressing wants—appealing to the eye by their magnitude, and often by their grandeur, and associated, in many cases, with the warmer impulses of humanity and personal safety—the labours of the mechanist and engineer acquire a contemporary celebrity, which is not vouchsafed to the results of scientific research, or to the productions of literature and the fine arts. ”

“ Mechanical engineering, as we understand it, could only fairly start in its wonderful progress after the mechanic had found ways of utilizing natural forces and energies, and of making the tools with which to produce these prime motors, through the operation of which all the arts could be given application in the production of wealth, multiplying the power of the unaided hand by making it in the performance of work the guide of greater powers, rather than the tool itself. ”

“ A MACHINE is an instrument by which force or motion may be transmitted and modified as to its quantity and direction. There are two ways in which a machine may be applied, and which give rise to a division of mechanical science into parts denominated STATICS and DYNAMICS; the one including the theory of equilibrium, and the other the theory of motion. When a machine is considered statically, it is viewed as an instrument by which forces of determinate quantities and direction are made to balance other forces of other quantities and other directions. ”

“ In all these cases the invention was devised by practical builders; and mechanical theory, though it can afterwards justify these structures, did not originally suggest them. They are not part of the result, nor even of the application of theory, but only of its exemplification. The authors of all these inventions are unknown; and the inventions themselves may be regarded as a part of the Prelude of the science of mechanics, because they indicate that the ideas of mechanical pressure and support, in various forms, are acquiring clearness and fixity. ”

“ This is followed by the mathematics necessary for the solution of the problems in machine design which are presented later, and a practical introduction to theoretical mechanics and the strength of materials. The various elements entering into machine design, such as cams, gears, sprocket wheels, cone pulleys, bolts, screws, couplings, clutches, shafting and flywheels have been treated in such a way as to make possible the use of the work as a textbook for a continuous course of study. It is easily comprehended and assimilated even by students of limited previous training. ”

“ This invention consisted in the contrivance of a scheme of mechanical notation which is generally applicable to all machinery whatsoever; and which is exhibited on a table or plan consisting of two distinct sections. In the first is traced, by a peculiar system of signs, the origin of every motion which takes place throughout the machinery; so that the mechanist or inventor is able, by moving his finger along a certain line, to follow out the motion of every piece from effect to cause, until he arrives at the prime mover. ”

“ Your first position is that of a master mechanic, who is capable of drawing plans and writing minutely a specification whereby the engineer may know what a well constructed machine is in every particular. He knows the parts and relations of both as constructor and operator, and you are supposed to be the foreman in the shop of repairs. The living person is the engine, nature the engineer, and you the master mechanic. ”

“ All machinery, whether it be printing-presses or automobiles or steam-engines, is the work of mechanical engineers, though in the matter of automobiles this has become a profession by itself, one of the minor branches known as automotive engineering. The mechanical engineer as a rule works26 within doors, just as the civil engineer works out of doors, and his work, consequently, is more confining. ”

“ Those interested in mechanics will discover for themselves the mechanical defects and unnecessary complications introduced into them. I was working under the supervision of fairly good mechanical engineers, so that defects might not be made too glaring. ”

“ But, on the other hand, the study of Mechanics, in its genuine form, as a branch of education, is fitted to give a most useful and valuable precision of thought on such subjects; and is the more to be recommended, since, in the general habits of most men’s minds, the mechanical conceptions are tainted with far greater obscurity and perplexity than belongs to the conceptions of number, space, and motion. ”

“ Is such a man to receive directions how to manage his machine from any passer-by, from persons who know nothing of mechanical laws, and of but little else, and never gave an hour’s thought to the simplest mechanical appliance? ”

“ As is seen above, the course of instruction in mechanical engineering includes some trade education. The engineer is dependent upon the machinist, the founder, the patternmaker, and other workers at the trades, for the proper construction of the machinery and structures designed by him. He is himself, in so far as he is an engineer, a designer of constructions, not a constructor. ”

“ As users of these tools we cannot begin to compare with the skilled workman of ancient days. Our progress is shown not in the development of skill, but in the loss of it. We have taken the tool out of the human hand and put it into an inanimate machine. It is only very recently that the tool was delivered to the machine and that act marked the dawn of the present remarkable mechanical era. ”

“ Many of our illustrations will be designedly drawn from very commonplace sources: by this means I would try to impress upon you that mechanics is not a science that exists in books merely, but that it is a study of those principles which are constantly in action about us. Our own bodies, our houses, our vehicles, all the implements and tools which are in daily use—in fact all objects, natural and artificial, contain illustrations of mechanical principles. ”