In cases of double or more forces, if lines are drawn from one another to rep resent all the forces at their angles, the resultant force is the line which completes the figure.
When the work to be done requires more force for its execution than can be generated in the time necessary for its completion, recourse must be had to a fly-wheel, which is a wheel having a heavy rim, so that the greater part of the weight is near the circumference. An other method consists in raising a weight, and then allowing it to fall. And another in condensing air, by great force, and then using its expansive force as required.
Uniformity in the motion of machinery is essential. The governor, in the steam engine, and a vane or fly of little weight, but large surface, which revolves rapidly, and soon acquires a uniform rate by the resistance of the air, are contrivances for steadying power.
Increase of velocity is effected by a band, passing round a large wheel, and then round a small spindle.
Diminiutioa of velocity is effected by systems of pulleys, or by transmission through a number of wheels.
Spreading the action of a force exerted for a few minutes over a large time, is one of the most useful employments of ma chinery, and the half minute which we spend in winding up a watch, is an ex ertion of force which, by the aid of a few wheels, is spread over 24 hours.
Machinery affords a sure means of rem edying the inattention of human agents, by instruments ; for instance, for count ing the strokes of an engine, or the num ber of coins struck in a press. The tell tale, a piece of mechanism connected with a clock, in an apartment to which a watch man has not access, reveals whether he has neglected, at any hour, to pull a string in token of his vigilance.
The precision with which all operations are executed by machinery, and the exact similarity of the articles made, produce economy in the consumption of all raw materials.
The accuracy with which machinery executes its work is, perhaps, one of its most important advantages. It would hardly be possible for a very skilful work man, with files and polishing substances, to form a perfect cylinder out of a piece of steel ; but this process, by the aid of the lathe and the sliding-rest, is the every day employment of hundreds of workmen.
'.1.‘he objections to machinery arise from the faulty distribution of its benefits to society, and the neglect and injustice of not fairly indemnifying those whose skill and capital is destroyed by new inventions. Machinery is, Wierefore, in the produc tion of cheap manufactures for exporta tion, and even for home consumption, to be regarded as a public benefit. But there are two parties, in regard to the ad vantages and disadvantages of machinery. The political economists, who consider society in the abstract, and look to gene ral results, are partisans of all means which produce at the least cost, and, there fore, of machinery. So, also, inventors, or their assignees, who manufacture cheap, and, for a time, sell at the established price, or with such small abatement of the manual price as secures the market, thereby making vast profits. But the working artisan, who, by a machine, is thrown out of an employment by which he and his forefathers have long subsist ed, and other manufacturers, who find themselves undersold and their trade de stroyed, are enemies of all new machinery. The one is unable to learn a new trade, or to excel in it in the maturity or decline of life, and has no reserved capital, on which to subsist in the intermediate pe riod; and the other, having embarked his capital in peculiar connections, finds it difficult, and even impossible, to with draw it and establish any new and pro fitable business—so that the first are gen erally reduced to pauperism, and the lat ter to bankruptcy. It is with each an individual—a personal affair, for which there is no compensation in the general benefit arising to the community, or in the aggrandizement of the inventor. Nevertheless, the community do benefit immediately and remotely, and it is, there fore, contended, that the community are thereby qualified to indemnify the imme diate sufferers, and that laws and arrange ments ought to be made, so as to effect this just and desirable purpose. This would reconcile the conflicting interests; inventions would then be more numerous and better encouraged, and a fair and reasonable compensation from the public stock would reconcile all parties to the progress and inventions of machinery.