These auxiliary agents are divided into two distinct classes—namely, hand-tools and machine-tools. The former are actuated directly by the human hand, and therefore require a certain degree of skill in conjunction with physical strength, while the latter are characterized by a definite limit of motion, and, though this motion may be produced by human strength, every available source of power may be substituted therefor. The rapid development of the civilized world during the nineteenth cen tury has been directly due to the ever-increasing success with which hand tools have become supplanted by machinery and muscular power by the force of moving water and air, by heat as applied through the steam engine, and by chemical action as utilized through expansive gases evolved from explosives, by electricity, etc.
Through the application of these forces the capacity and facility of mechanical operations have been increased to such an extent that the ingenuity of inventors has during the past half century been chiefly directed to the development of mechanisms through which the natural forces arc to he employed.
The application of such mechanisms, together with their construction, constitutes what is termed the Utilitarian or Industrial Arts, as distin guished from the ?Esthetic or Fine Arts. In every branch of the rian arts mechanisms of a more or less complicated structure arc applied in forms as varied as are the purposes to be subserved, and a consideration of these mechanisms forms the general subject of Applied Mechanics. The present treatise, therefore, is devoted to a description of a vast range of apparatus comprising the requisite appliances for effecting the successive changes in the condition and relation of materials, and for transforming them into the multitude of objects required by civilized man. Not the least important of these appliances are those constructed for the purpose of controlling the free forces of nature or of converting its latent forces into serviceable conditions.
Manual appliances, or hand-tools, have been developed, in the course of progress, from such primitive forms as the flints of the Palmolithie Period, the stone knives and stone saws of the Glacial or Stone Age, and the more perfected implements of the Bronze Epoch, to a stage where they have been gradually merged into the more complicated mechanisms known as machine-tools; hand-tools are therefore, in the main, to be considered as embodying the primary stage of technical development.
No classification of•mechanical appliances can be made which will be so definite as distinctly to differentiate all the numerous forms of mechan ism, yet in general they may be arranged into a number of classes, dis tinguished by the nature of the function for which the various appliances are designed. These several classes are the following—namely, Machine tools, Prime-movers, Machines for Convection, Measuring-machines, and Special Appliances.
Machine-tools may be divided into two categories—namely, (i) those which deal with substances in their natural or crude form, and (2) those which are designed to manipulate the partially or fully prepared materials in the more advanced or final stages of fabrication.
The first category may be subdivided into three classes—namely, (i) appliances for compressing or crushing, (2) appliances for abrasion or grinding, and (3) appliances for incision or cutting.
The category of manipulating-machines must necessarily be subdivided according to the work for which the various machines are designed. The most important of these manipulating-tools are comprised in the following classes—namely, machines for agricultural purposes, machines for working wood and metals, machines for making textiles, etc.
Of the second subdivision, comprising prime-movcrs or machines for the production of mechanical force, through which motive power is evolved from muscular energy, from the force of moving air or water, or from heat or electricity, the following are the main class-divisions namely, tread-mills, wind-wheels, water-wheels, steam-boilers, steam engines, caloric or hot-air engines, gas-engines, and electric motors.
The third general subdivision of mechanical appliances comprises the various means (i) for the transportation of solids, (2) for the convection of liquids and gases, and (3) for the transmission of power. These may be classified as follows—namely, (r) a, vehicles, b, hoisting-machines; (2) a, pumps, b, blowers and fans; and (3) a, gearing, b, shafting, c, pulleys, and a', belting.
The fourth general subdivision, that of measuring-machines, includes the various appliances for the measurement of weight, of time, and of other quantities. These consist of (r) scales, (2) timepieces, and (3) meters in general.
Finally, there is to be considered an extensive range of individual appliances, among which may be enumerated writing-machines, typeset ting-machines, calculating-machines, and other machines designed for specific purposes.