Robert Henry Thurston

“ The power of the steam-engine, and its inconceivable importance as an agent of civilization, has always been a favorite theme with philosophers and historians as well as poets. As Religion has always been, and still is, the great moral agent in civilizing the world, and as Science is the great intellectual promoter of civilization, so the Steam-Engine is, in modern times, the most important physical agent in that great work. ”

“ CHAPTER VIII. THE PHILOSOPHY OF THE STEAM-ENGINE. Its Application; its Teachings respecting the Construction of the Engine and its Improvement.
“Oftentimes an Uncertaintie hindered our going on so merrily, but by persevering the Difficultie was mastered, and the new Triumph gave stronger Heart unto us.”—Raleigh.
“If everything which we cannot comprehend is to be called an impossibility, how many are daily presented to our eyes! and in contemning as false that which we consider to be impossible, may we not be depreciating a giant’s effort to give an importance to our own weakness?”—Montaigne. ”

“ Judging from the rapid strides the steam-engine has made during the last forty years to become a universal first-mover, and from the experience that has arisen from that extension, we feel convinced that every invention which diminishes its size without impairing its power brings it a step nearer to the assistance of the ‘world’s great laborers,’ the husbandman and the peasant, for whom, as yet, it performs but little. ”

“ All over the country, and even on the Continent of Europe, and in America, thousands of mechanics, and many men of mechanical tastes in other professions, were familiar with the principles of the new machine, and were speculating upon its value for all the purposes to which it has since been applied; and a multitude of enthusiastic mechanics, and a larger multitude of visionary and ignorant schemers, were experimenting with every imaginable device, in the vain hope of attaining perpetual motion, and other hardly less absurd results, by its modification and improvement. ”

“ The steam-engine had taken a form which made it inconceivably valuable to the world, at a time when no more efficient means of raising water was available at the most valuable mines than horse-power; but the people, greatly as it was needed, were not yet sufficiently intelligent to avail themselves of the great boon, the acceptance of which was urged upon them with all the persistence and earnestness which characterizes every true inventor. ”

“ The Railroad, which now, by the adaptation of steam to the propulsion of its carriages, became the successful rival of the system of transportation of which an account has just been given, was not a new device. It, like all other important changes of method and great inventions, had been growing into form for ages. The ancients were accustomed to lay down blocks of stone as a way upon which their heavily-loaded wagons could be drawn with less resistance than on the common road. ”

“ There is nothing in the future more sure than the great triumphs which that epoch is to achieve. It has already advanced to some glorious conquests. What miracles of invention now crowd upon us! Look abroad, and contemplate the infinite achievements of the steam-power. ”

“ The great geological changes which buried these forests under superincumbent strata of rock and earth resulted in the formation of coal-beds, and the storage, during many succeeding ages, of a vast amount of carbon, of which the affinity for oxygen remained unsatisfied until finally uncovered by the hand of man. Thus we owe to the heat and light of the sun, as was pointed out by George Stephenson, the incalculable store of potential energy upon which the human race is so dependent for life and all its necessaries, comforts, and luxuries. ”

“ If, in any engine, a reversal effects complete inversion of all the physical and mechanical details of its operation, it is a perfect engine, and produces maximum effect with any given quantity of heat and with any fixed limits of range of temperature. ”

“ When a new form of steam-engine is likely to be introduced, if at all, can be scarcely even conjectured. It seems evident that its success is to be secured, if a revolution is ever to occur, by the adoption of high steam-pressures, of great piston speeds, by care and skill in design, by the use of exceptionally excellent materials of construction, [481] by great perfection of workmanship, and by intelligence in its management. ”

“ The genius of Worcester, and Morland, and Savery, and Desaguliers, had, in the first period of the [145] application of the power of steam to useful work, effected a beginning which, looked upon from a point of view which exhibits its importance as the first step toward the wonderful results to-day familiar to every one, appears in its true light, and entitles those great men to even greater honor than has been accorded them. ”

“ Steam must enter the machine at the highest possible temperature, must be protected from waste, and must retain, at the moment before exhaust, the least possible amount of heat. He whose inventive genius, or mechanical skill, contributes to effect either the use of higher steam with safety and without waste, or the reduction of the temperature of discharge, confers a boon upon mankind. ”

“ Steam-engine building establishments sprang up wherever a mechanic had succeeded in erecting a workshop and in acquiring a local reputation as a worker in metal, and many of Watt’s workmen went out from Soho to take charge of the work done in these shops. Nearly all of the great establishments which are to-day most noted for their extent and for the importance and magnitude of the work done in them, not only in Great Britain, but in Europe and the United States, came into existence during this second period of the application of the steam-engine as a prime mover. ”

“ Hence, the same invention is frequently brought out in several countries, and by several individuals, simultaneously. Frequently an important invention is made before the world is ready to receive it, and the unhappy inventor is taught, by his failure, that it is as unfortunate to be in advance of his age as to be behind it. Inventions only become successful when they are not only needed, but when mankind is so far advanced in intelligence as to appreciate and to express the necessity for them, and to at once make use of them. ”

“ They are now fully-developed and well-established systems of natural philosophy. Yet, like that of the steam-engine and of its companion heat-engines, their growth has by no means ceased; and, while the student of science cannot do more than indicate the direction of their progress, he can readily believe that the beginning of the end is not yet reached in their movement toward completeness, either in the determination of facts or in the codification of their laws. ”

“ Hautefeuille, if we may judge from evidence at hand, was the first to propose the use of a piston in a heat-engine, and his gunpowder-engine seems to have been the first machine which would be called a heat-engine by the modern mechanic. The earlier “machines” or “engines,” including that of Hero and those of the Marquis of Worcester, would rather be denominated “apparatus,” as that term is used by the physicist or the chemist, than a machine or an engine, as the terms are used by the engineer. ”

“ The maximum conductivity of flow of heat for any given material is secured by so designing the boiler as to secure rapid, steady, and complete circulation of the water within it. The maximum rapidity of transfer throughout the whole area of heating-surface is secured, usually, by taking the feed-water into the boiler as nearly as possible at the point where the gases are discharged into the chimney-flue, withdrawing the steam nearer the point of maximum temperature of flues, and securing opposite directions of flow for the gases on the one side and the water on the other. ”

“ Steam-boilers.—The steam supplied to the forms of stationary engine which have been described is generated in steam-boilers of exceedingly varied forms. The type used is determined by the extent to which their cost is increased in the endeavor to economize fuel by the pressure of steam carried, by the greater or less necessity of providing against risk of explosion, by the character of the feed-water to be used, by the facilities which may exist for keeping in good repair, and even by the character of the men in whose hands the apparatus is likely to be placed. ”

“ Force is that which produces, or tends to produce, motion, or change of motion, in bodies. It is measured statically by the weight that will counterpoise it, or by the pressure which it will produce, and dynamically by the velocity which it will produce, acting in the unit of time on the unit of mass. ”

“ We find kinetic energy in the motion of the winds and the flow of running water, in the heat-motion of the sun’s rays, in heat-currents on the earth, and in many intermittent movements of bodies acted on by applied forces, natural or artificial. The potential energy of fuel and of food has already been seen to have been derived, at an earlier period, from the kinetic energy of the sun’s rays, the fuel or the food being thus made a storehouse or reservoir of energy. ”

“ The steam, with its store of heat-energy, passes through tortuous pipes and passages to the steam-cylinder of the engine, losing more or less heat on the way, and there expands, driving the piston before it, and losing heat by the [459] transformation of that form of energy while doing mechanical work of equivalent amount. But this steam-cylinder is made of metal, a material which is one of the best conductors of heat, and therefore one of the very worst possible substances with which to inclose anything as subtile and difficult of control as the heat pervading a condensible vapor like steam. ”

“ But this combination of lightness with power is only attained at the expense of a certain regularity of action which can only be secured by greater water and steam capacity in the boiler. The small quantity of water contained within the boiler makes it necessary to give constant attention to the feed, and the tendency, almost invariably observed, to serious foaming and priming not only compels unintermitted care while running, but even introduces an element of danger which is not to be despised, even though the machine be in charge of the most experienced and skillful attendants. ”

“ It is estimated that the total steam-power of the world is about 15,000,000 horse-power, and that, were horses actually employed to do the work which these engines would be capable of doing were they kept constantly in operation, the number required would exceed 60,000,000.
Thus, from the small beginnings of the Comte d’Auxiron and the Marquis de Jouffroy in France, of Symmington in Great Britain, and of Henry, Rumsey, and Fitch, and of Fulton and Stevens, in the United States, steam-navigation has grown into a great and inestimable aid and blessing to mankind. ”

“ The coal carried by a steam-vessel is not only an item of great importance in consequence of its first cost, but, displacing its weight or bulk of freight which might otherwise be carried, it represents so much non-paying cargo, and is to be charged with the full cost of transportation in addition to first cost. The best of steam-coal is therefore usually chosen for steamers making long voyages, and the necessity of obtaining the most economical engines is at once seen, and is fully appreciated by steamship proprietors. ”

“ It began then to be generally understood that expansion of steam produced economy, and mechanics and inventors vied with each other in the effort to obtain a form of valve-gear which should secure the immense saving which an abstract consideration of the expansion of gases according to Marriotte’s law would seem to promise. The counteracting phenomena of internal condensation and reëvaporation, of the losses of heat externally and internally, and of the effect of defective vacuum, defective distribution of steam, and of back-pressure, were either unobserved or were entirely overlooked. ”

“ Scientific research, as we have seen, has proved that, in all known varieties of heat-engine, a large loss of effect is unavoidable from the fact that we cannot, in the ordinary steam-engine, reduce the lower limit of temperature, in working, below a point which is far above the absolute zero of temperature—far above that point at which bodies have no heat-motion. ”

“ The most palpable of the advantages of the rotary engine are the reduction in the size of the engine, claimed to result from the great velocity of the piston; the avoidance of great accidental strains, especially noticed in propelling ships; and a great saving of the power which is asserted to be expended in the reciprocating engine in overcoming the inertia while changing the direction of the motions. These advantages adapt the rotary engine, in an especial manner, to the driving of a locomotive or steam fire-engine. ”

“ Where much power is required, the stationary engine is usually an horizontal direct-acting engine, having a more or less effective cut-off valve-gear, according to the size of engine and the cost of fuel. A good example of the simpler form of this kind of engine is the small horizontal slide-valve engine, with independent cut-off valve riding on the back of the main valve—a combination generally known among engineers as the Meyer system of valve-gear. This form of steam-engine is a very effective machine, and does excellent work when properly proportioned to yield the required amount of power. ”

“ When a fire is made on the altar, the heat produced expands the confined air, and the liquid is driven up the tube, issuing from the vessel in the hand of the figure standing by the altar, which thus seems to be offering a libation. This toy embodies the essential principle of all modern heat-engines—the change of energy from the form known as heat-energy into mechanical energy, or work. It is not at all improbable that this prototype of the modern wonder-working machine may have been known centuries before the time of Hero. ”

“ The new establishments usually grew out of older shops of a less pretentious character, and were managed by men who had been trained by Watt, or who had had a still more awakening experience with those who vainly strove to make [147] up, by their ingenuity and by great excellence of workmanship, the advantages possessed at Soho in a legal monopoly and greater experience in the business.
It was exceedingly difficult to find expert and conscientious workmen, and machine-tools had not become as thoroughly perfected as had the steam-engine itself. ”