Over the whole system of 16.5 kilometers, which was also tested when no air was being taken off, there were four reservoirs of considerable size, and which offered a large resistance with a corresponding loss of pressure; on the line there were also 23 siphons and 42 stop valves.

These trials were repeated several times to secure accuracy, and the speed of the air was brought to 49 ft. a second. The results obtained in one of these trials may be taken as an example. The main between the Rue St. Fargeau and the Fontaine au Roi, on which there are no collecting reservoirs, but three siphons and eight stop valves, gave, with an average speed of 21 ft. 3 in., a loss in pressure of 0.05 atmosphere for each kilometer of main.

From these experiments it would appear that, assuming a speed of 21 ft. per second, a loss in pressure of one atmosphere would correspond to a distance of 20 kilometers; that is to say, a central station could extend its mains on all sides with a radius of 20 kilometers, and the motors at the ends of the lines would receive the air at a pressure 15 lb. less than at the central station. Professor Riedler states that as an actually measured result, the velocity of the air through the mains of the St. Fargeau system is 19 ft. 8 in. per second, and that the loss in pressure per kilometer is 0.07 atmosphere. From this it follows that including the resistances due to the four reservoirs, and other obstructions actually existing, an allowance of one atmosphere loss on a 14 kilometer radius is ample. By increasing the initial pressure of the air, much better results can be obtained, and future attention in practice should be devoted to this point. The amount of work required to compress air does not increase in the same ratio as the pressure, and for this reason considerable economy can be effected at the first stage, and the loss in the mains will be reduced.

Passing to another point of the same subject, Professor Riedler considers the best dimensions that should be given to the mains. Resistance decreases with an increase in the diameter of these and in direct ratio to their diameter; for this reason—still assuming a pressure corresponding to a velocity of 20 ft. per second—with a fall of one atmosphere, a length of 40 kilometers could be succesfully worked.

The mains of the new réseau for the Quai de la Gare station are 19.69 in. in diameter; they are built up of steel plates riveted, and this Professor Riedler considers to have been a serious error on account of the extra resistance offered by the large number of rivet heads.

The following may be taken as a brief summary of Professor Riedler's conclusions: Recent improvements in central station practice have resulted in an increased efficiency of about 30 per cent. in the compressors, but this benefit can only be realized when the new station is in operation. That the small and very imperfect air engines in use on the system give an efficiency of 50 per cent., while with ordinary steam engines driven by air an efficiency of 80 per cent. can be reached with a very small expenditure of fuel for heating the air before admitting it into the motor. That special attention should be given to the improvement of air engines, and that with increased initial pressures at the central station the distance of the transmission can be very considerably augmented. Finally, Professor Riedler claims that power can be transmitted by compressed air more conveniently and more economically than by any other means.

THE BUILDERS OF THE STEAM ENGINE—THE FOUNDERS OF MODERN INDUSTRIES AND NATIONS.¹

By Dr. R.H. THURSTON, Director of Sibley College, Cornell University.

Papin, Worcester, Savery, were the authors of the period of application of the power of steam to useful work in our later days. The world was, in their time, just waking into a new life under the stimulus of a new freedom that, from the time of Shakespeare, of Newton, and of Gilbert, the physicist, has steadily become wider, higher, and more fruitful year by year. All the modern sciences and all the modern arts had their reawakening with the seventeenth century. Every aspect of freedom for humanity came into view in those days of a new birth. Both the possibility of the introduction of new sciences and of new arts and the power of utilizing all new intellectual and physical forces came together. The steam engine could not earlier have taken form, and, taking form, it could not have promoted the advance of civilization in the earlier centuries. The invention becoming possible of development and application, the promotion of the arts and of all forms of human activity became a possible consequence of its final successful introduction into the rude arts that it was to so effectively promote and improve.

But the work of these inventors was in itself but little more important than that of the Greek inventor of the steam ælopile, for each brought forward a machine which was, from a business point of view, utterly impracticable, and which, in each case, only served to show that a better device might prove useful and lead the way to its introduction. The merit of the inventors of the eighteenth century was that they were able to lead the way, to point out the path to success, to furnish evidence of the value of the coming, crowning invention. The "fire engines," as they were then called, of these now famous men were merely contrivances by the use of which the pressure of confined steam of high tension could be brought to act on the surface of a mass of confined water, forcing it downward into pipes through which it was led off and upward to a higher level; and thus a mine could be drained, ineffectively and expensively to be sure, but vastly more satisfactorily than by the animal power of the time. The machine of Savery was the best of all; but that was only a somewhat improved and manageable rearrangement of the engines of Papin and Worcester. And, after all, Papin, the greatest man of science perhaps of his time, died in poverty; Worcester languished in prison his whole life, and the later efforts of his widow brought nothing by way of a return for his invention; nor did either they or their successor, Morland, make the introduction of the engine either general or remunerative.

Savery, coming on the stage at more nearly the right time to seize upon an opportunity, gained more than either of his predecessors; but we have no evidence that he ever acquired any large compensation or met with any remarkable business success in the introduction of the rude engine which bore his name; nor did Desaguliers, the great philosopher, or even Smeaton, the great engineer, of the later years of that century, make any great success of it. It was reserved for Watt to reap the harvest. But, though he so effectively reaped where his predecessors had sown, Watt is not the greatest of the inventors of the steam engine, if we rate his standing by the magnitude of the improvement which marked his reconstruction of the engine.

It was NEWCOMEN who made the modern steam engine.

When Newcomen came forward the labors of Worcester in Great Britain had sufficed to attract the attention of all intelligent men to the character of the problem to be solved, and to convince them of its importance and promise. The work of Savery had shown the practicability of the solution of the problem, both in mechanics and finance. He succeeded, though under great disadvantages and comparatively inefficiently. Once the task had been performed, though ever so rudely, the rest came easily and promptly. The defects of the Savery system were at once recognized; its great wastes of heat and of steam were noted, and the fact that they were inherent in the system itself was perceived. A complete change of type of machine was obviously requisite; it was this which constituted the greatest invention in the whole history of the steam engine, from Hero's time to our own; and to Newcomen we owe more than to any other man who ever lived, the value of the invention itself being considered, and the importance of the services of its introducer being left out of consideration. No such complete and vital improvement and modification of the machine has ever been effected by any other man, Watt and Corliss not excepted. Newcomen and his comrade Calley—we do not know how the honors should be divided—produced the modern steam engine. Its predecessor, the Savery engine, had been a mere steam "squirt." Newcomen constructed an engine. Savery built a simple combination of cylindrical or ellipsoidal vessels which wastefully and at once performed all the several offices of engine, pump, condenser, and boiler; Newcomen divided the several elements among as many parts, each especially adapted to the performance of its task in the most effective manner—the condenser excepted; for that was Watt's principal invention—and thus produced the first steam engine in the modern sense of that term.

It was Newcomen, not Watt, who gave us the train of mechanism that we now call the steam engine. It is to Newcomen, rather than Watt, that we owe the highest honors as an inventor in this series of the most important of all the products of the inventive genius of mankind. Newcomen brought into existence a new, the modern, type of engine, and effected the greatest revolution that has been recorded in the history of the arts. Without Newcomen, there might have been no Watt; without Watt, there very possibly may not even yet have been brought into existence that giant of our time, whose mighty powers are employed more effectively than ever those of Aladdin's genii, in building palaces, in transporting men and material, in doing the work of the whole world; promoting the welfare of the race, in a single century, more than had all the forces of matter and mind together in the whole previous history of the world. Newcomen laid down a foundation beneath our whole economic system, out of sight, almost, but the essential base, nevertheless, on which Watt and his successors have carried up the great superstructure which seems to us to-day so imposing; which is so tremendous in magnitude, importance, and result. If to any one man could be assigned the credit, it is Newcomen who is to be considered the inventor of the steam engine.

James Watt, indisputably the great inventor that he was, found the steam engine ready to his hand, applied himself to its improvement, and made it substantially what it is to-day. His most important work, the most unique service performed by him, was, however, that of its adaptation and introduction to do the work of the world. James Watt was the inaugurator of the era of refinement of the machine already invented, and the greatest of its builders and distributors. His inventions were all directed to the improvement of its details, and his labors to its introduction and its application to the myriad tasks awaiting it. By the hands of Watt it was made to pump water, to spin, to weave, to drive every mill; and he it was who gave it the form demanded by Stephenson, by Fulton, by the whole industrial world, for use on railway and steamboat, and in mill and factory, throughout the civilized countries of the globe. It was this great mechanic who showed how it might be made to do its work with least expense, with highest efficiency, with greatest regularity, with utmost concentration of power.

The grand secret of his success was historical and economic, as much as scientific and mechanical. He brought out his inventions just when the world was economically and historically ready for them. The age of authority was past, that of freedom was come; the period of political and ecclesiastical tyranny was gone by, and that of the spontaneous development of man was arrived. The great invention was offered to a world ready and needing it, and, more than all, competent, for the first time in history, to make and use it.

James Watt was himself a product of the modern scientific spirit. He was a man so constituted mentally that he could apply scientific methods to problems which his logical and clairvoyant mind could readily and exactly formulate the instant he was led to their consideration in the natural course of his progress. He was the ideal great inventor and mechanic. With inventive genius he combined strong common sense—not always a quality distinguishing the inventor—clear perception, breadth of view, and scientific method and spirit in the treatment of every question. His natural talent was re-enforced by an experience and an environment which led him to develop these ways and this mental habit. His trade was that of an instrument maker, his position was that of custodian and repairer of the apparatus of Glasgow University. He had for his daily companions and stimulus the great men and ozonized atmosphere of that famous institution. He kept pace with advancing science, and was imbued, both naturally and through contact with its promoters, with that ambition and those aspirations which are the life element of all progress, whether scientific or other. He was aware of the nature of the problems seeking solution at the time, and familiar with the state of his own art and that of the great mechanicians about him. Everything was favorable to his progress, so soon as he should be given an opportunity to take a step in advance and to come into sight at the front. The man and the time were both ready, and all conditions, internal and external, social and personal, were favorable to his development.

The invention upon which Watt was to improve was at his hand. A word in regard to its status at the moment will throw some light upon that of Watt and his creation. Newcomen had, as we have seen, produced the modern type of steam engine as an original and wholly novel invention. But this machine, marvelous as an advance upon pre-existing forms of the steam engine, was still, as seen in the light of recent knowledge and experience, exceedingly defective. The purpose of a steam engine is to convert into usefully applicable power the hidden energy of fuel, stored ages ago in the earth, by transformation, through the action of vegetation, from the original form, the heat of the sun, into an available form for reconversion, through thermodynamic operations. In this process of reconversion, whatever the nature of the machine used in the operation, there are invariably wastes, both of heat required for conversion into power and of the power thus produced. That machine which effects the most complete transmutation of the heat supplied it into mechanical power, which wastes the least amount of heat supplied and of power produced, is the best engine, and constitutes an advance over every other.

It was this reduction of wastes that made the Newcomen engine so much superior to that of Savery. The latter was by far the simpler and less costly construction; but its enormous losses, both of heat and of power, mainly the former, however, made it an extravagant expenditure of money to buy and use it. The Newcomen engine, costly and cumbrous, comparatively, nevertheless wasted so much less heat and steam and fuel that no one could afford to buy the cheaper machine. Before considering what Watt accomplished, we may find it profitable to examine into the nature of the wastes which characterized this later and better machine on which he effected his improvements.

The Newcomen engine consisted of a steam boiler, a steam cylinder, a beam and a set of pumps. By making the boiler do its work separately, the engine acting independently, and the pumps as a detached portion of the mechanism, this inventor had reduced to an enormous extent those wastes of heat and of steam and of fuel which were unavoidable in the older machines in which all these parts were represented by a single vessel, or by two at most, in each element. In the Savery engine, the steam entering first heated up the interior of the working vessel to its own temperature, and held it at that temperature in spite of the cooling influence of the water present. This consumed large quantities of heat. It then was compelled to surrender probably much greater quantities still to the water itself, coming in direct contact as it did with its surface. If the water was agitated, either by the currents produced during its ingress or by the impact of the steam entering the vessel, this heating action penetrated to considerable depths and perhaps even warmed the whole mass very far above its initial temperature. This constituted another and a very serious loss. Then, again, as the water was gradually driven out of the containing vessel by the steam pressing on its surface, new portions of the vessel and new masses of water were continually brought in contact with the hot steam, taking its full temperature, and thus, often, probably, finally heating the whole mass of the forcing vessel, and a large proportion of the water as well, up to the temperature, approximately at least, of the steam itself. Thus in many instances, if not always, vastly more heat and steam were wasted, in this undesirable heating of water and forcing vessel, than were usefully employed in the legitimate work of raising the water to a higher level. In fact, in some cases in which these quantities were measured, the wastes were one hundred times as much as the work done. One per cent. of the heat supplied did the work; while ninety-nine per cent. was thrown away. One dollar or one shilling expended for fuel to do the work was accompanied by an expenditure of ninety-nine dollars or shillings thrown away, because of the imperfections of the system and machine. The whole history of the development of the steam engine has been one of gradual reduction of these wastes; until to-day, our best engines only compel us to spend five dollars for wastes to each dollar paid out for useful work. A business man would think that amply extravagant, however, and the man of science is continually seeking methods of evading these losses, a large proportion of which are now apparently unavoidable in heat engines, by finding some new system of heat and energy transformation.

Watt was the instrument maker and repairer at Glasgow University in the year 1763. His companions were, among others, the professors of natural philosophy and of mathematics in the university. Their conversation and their frequent presentation of practical and scientific questions and problems stimulated his naturally inquiring and inventive mind to the pursuit of a thousand interesting and promising schemes for the improvement of existing methods and machinery. Dr. Robison, then a student, suggested the invention of a steam carriage for use on common roads, and the young mechanician at once began experiments that, resulting in nothing at the time, were nevertheless continued, in one or another form, until all modern applications of steam came into view. Dr. Black taught Watt chemistry, then a newly constructed science, and led him on to the discovery, finally made by them independently, of the fact and the magnitude of the latent heat of steam; the discovery coming of a series of scientifically planned and accurately conducted investigations, such as the man of science of to-day would deem creditable. The treatises of Desaguliers and others on physics gave Watt a knowledge of that domain of natural phenomena which stood him in good stead later, when he attempted to apply its principles to the reduction of the wastes of the steam engine.

It was while at Glasgow University, working under such influences and in such an atmosphere of intellectual activity, that the accident of the Newcomen model engine needing repair brought to the mind of Watt the opportunity which, availed of at once, made him famous and gave the world its greatest aid, its most powerful servant. The observing mind of the great mechanic immediately noted its defects, sought their causes, found their remedy. He discovered, at once, that the quantity of steam entering the cylinder of the little engine has four times the volume of the cylinder receiving it: in other words, three-fourths of that steam must be condensed immediately on entrance. This meant, evidently, that only one-fourth of the steam supplied was utilized, and even then inefficiently, in doing its work. The reason of this was as easily seen, immediately the fact was revealed. As Watt himself expressed it, the causes of this loss, causes which would obviously be exaggerated in a small engine, were: "First, the dissipation of heat by the cylinder itself, which was of brass and both a good conductor and a good radiator. Secondly, the loss of heat consequent upon the necessity of cooling down the cylinder at every stroke in producing the vacuum. Thirdly, the loss of power due to the pressure of vapor beneath the piston, which was a consequence of the imperfect method of condensation." This much determined, the next step looked toward the confirmation of his conclusions and the remedy of the defects.

To meet the first difficulty he made a cylinder of wood, soaked in oil and baked, a non-conducting and non-radiating material. Then he was able to determine with some accuracy the quantities of steam and injection water used in the engine; and a comparison with the original cylinder and its operation showed that not only four times the quantity of steam, but also four times the amount of injection water was used as was necessary, assuming wastes checked. Further scientific research on the part of Watt gave him measures of specific heats of the metals and of wood, the specific volumes of steam at various working pressures, the evaporative efficiency of boilers, the pressures and temperatures of steam in the boiler under specified conditions, the quantities of steam and of water required for the operation of his little condensing engine.

Then came his enunciation of the grand principle of economy in the construction and operation of the steam engine: "Keep the cylinder as hot as the steam which enters it," as he expressed it. This was Watt's guiding principle, as it has been that of all his successors in the improvement of the economic performance of the steam engine and of all other heat engines. The great source of waste is the dispersion of heat, uselessly, which should be applied to the production of work by its transformation, thermodynamically, into the latter form of energy. The second form of waste is that of power thus produced in the unprofitable work of moving the parts of the engine itself; and the third is that of heat by transfer, without transformation, by conduction and radiation to surrounding bodies. In modern engines, the latter is but three or five per cent., in the best cases; the second waste constitutes perhaps ten per cent.; while the first of these losses amounts very usually to seventy per cent., of which last one-third or one-fourth is of the kind discovered by Watt, the rest being the thermodynamic waste incident to all known methods of operation of heat engines, and apparently unavoidable. In our very best and largest engines, the waste found by Watt to constitute three fourths of all heat supplied has been brought down to ten per cent., a fact which well exemplifies the advances made since his time of apprenticeship by himself and his successors of this nineteenth century. The steam engine of to-day, in its most successful operation, gives us twenty-five times as much power from a pound of coal as did the engine that the great inventor sought to improve: this is the magnificent fruit of that one discovery of James Watt, and of application of the simple principle which he so concisely and clearly stated.

The method adopted by Watt to secure a remedy, so far as practicable, of this defect of the older machine was as simple and as perfect as was the principle which it embodied. He first removed from the cylinder the prime source of its wastes; providing a separate condenser, and thus avoiding the repeated chilling of its surfaces by the cold water used in condensing the steam at exhaust, and also permitting its strokes to be made with far greater frequency, thus giving less time for cooling by the influence of the remaining vapors after condensation. He next went still further, and provided the cylinder with a closed top, keeping out the air, and a "jacket" of hot boiler steam to keep it as hot as the steam which entered it. These were the two great improvements which converted the first real steam engine into an economical form of heat engine and essentially finished the work so grandly begun by Newcomen and Calley. These changes gave us the modern steam engine; and these are Watt's first and greatest, but by no means only, contributions to the production of the modern world with all its comforts, its luxuries and its opportunities for material, intellectual and moral advancement of individual and of race. His work was to this extent complete in 1765.

But Watt did not stop here. There still remained for him the no less important and the, in some senses, still more imposing, work of finding employment for the new servant of mankind and of setting it at its work of giving the human arm a thousand times greater strength, to the mind of man uncounted opportunities to promote the advancement of knowledge, of civilization, of every good of the race. His was still the task of adapting the new machine to all the purposes of modern industry. It had been hitherto confined to the task of raising water from the depths of the mine; it was now to be harnessed to the railway train; to be made to drive the machinery of the mill, to apply its marvelous power to the impulsion of the river boat and ocean steamer; to furnish energy, through endless systems of transfer and use, to every kind of work that man could devise and should invent. All this meant the giving of the machine forms as various as the purposes to which it was to be devoted. It had previously only raised and depressed a rod; it must now turn a shaft. It had then only operated a pump; it must now turn a mill, grind our grain, spin our threads, weave our cloths, drive our shops and factories, supply the powerful blast of the iron furnace. It must be made to move with the utmost conceivable regularity, and must, with all this, do its work in the development of the hidden energy of the fuel, with the greatest possible economy, through the expansion of its steam. All this was achieved by James Watt.

The invention of the double-acting engine, in which the impulsion of the steam is felt both in driving the piston forward and in forcing it backward, both upward and downward, the application of its force through crank and fly wheel, the creation of an automatic system of governing its speed, and the discovery of the economy due to its complete expansion, were all improvements of the first magnitude, and of the greatest practical importance; and all these were in rapid succession brought into existence by the creative mind that had apparently been brought into the world for the express purpose of giving to the hand of man this mighty agent, to perfect the mightiest power that mind of man has yet conceived.

But to do the rest required more than inventive genius and mechanical skill. It demanded capital and the stored energy of labor and genius in other fields, directed by the mind of a great "captain of industry." This came to Watt through Matthew Boulton, a manufacturer of Birmingham, whose father and ancestors had gradually and toilsomely, as always, accumulated the property needed for the prosecution of a great business. The combination of genius and capital is always an essential to success in such cases; and good fortune, a Providence, we may well say, brought together the genius and the capitalist to do their work, hand in hand, of providing the world with the steam engine. Hand in hand they worked, and all the world to-day, and the race throughout its future life, must testify gratitude for the inexpressible obligations under which these two men have placed them, doing the work of the world.

Boulton & Watt, the capitalist with the inventor, gave the world the steam engine, finally, in such form and in such numbers that its permanent establishment as the servant of man was insured. The capitalist was as essential an element of success as was the inventor, and, in this instance, as in a thousand others, the race is indebted to that much-abused friend of the race, the capitalist, for much that it enjoys of all that it desires. The industry and patience, the skill and the wisdom required for the accumulation of this energy stored for future use in great enterprises is as important, as essential, as inventive power or any other form of genius. Talent and genius must always aid each other. This firm was established in 1764 and its main resources, aside from the bank account, were Watt's patent, about expiring, and Watt's genius, and Boulton's talent as a man of business. The patent was extended for twenty-four years, the new inventions of Watt, now beginning to pour from his prolific brain in a wonderful stream, were also patented, and the whole works were soon employed upon the construction of engines for which numerous orders soon began to pour in upon the now prosperous builders. The patent law established Boulton and Watt and the firm paid back the nation with handsome usury, giving it unimaginable profits indirectly through its control of the work of the world and large profits directly through the business brought them from all parts of the then civilized globe. There has never, in the history of the world, been a more impressive illustration of the value to a nation of that generous public policy, that simply just legislation, which gives to the man of brain control of the products of his mind. For a hundred years, Great Britain has, largely through her encouragement of the inventor and her protection of his mental property by securing the fruits of his labors, in fair portion, to him, gained the power of dictating to the world and has gained an advance that cannot be measured. Watt and Arkwright and Stephenson and Crompton and their ilk, protected by their government and its patent laws, made their country the peaceful conqueror of the world. The story of the work of the inventor is a poem of mighty meaning and of wonderful deeds. The inventor proved himself a mightier magician than ever the world had seen.

"A creature he called to wait on his will,
Half iron, half vapor—a dread to behold;
Which evermore panted, and evermore rolled,
And uttered his words a millionfold."

Such was the outcome of this grand modern "trust," a combination of the wisest legislation, the most brilliant invention, and the most wisely applied capital. There are "trusts" of which the outcome is most beneficent.

Since the days of Watt, the improvement of the steam engine and the work of inventors has been confined to matters of detail. All the fundamental principles were developed by Watt and his predecessors and contemporaries and it only was left to his successors to find the best ways of carrying them into effect. But these matters of detail have been found to involve opportunities to make enormous strides in the direction of securing improved efficiency of the machine. The further application of the principle which led Watt to his greatest inventions; of the principle, keep the cylinder as hot as the steam which enters it, of that which he enunciated relative to the advantage of expanding steam, and of that affecting the regulation of the machine; have reduced the costs of steam and of fuel to a small fraction of their earlier magnitude. One ton of engine to-day does the work of eight or ten in the time of Watt: one pound of fuel or of steam gives to-day ten times the power then obtained from it. A steamship now crosses the Atlantic in one-eighth the time required by the famous "liner" of the "Black Ball Line." The wastes of the engine have been brought down from above eighty per cent. to eight; and a half-ounce of fuel on board ship will now transport a ton of cargo over a mile of ocean.

FREDERICK E. SICKELS gave us the first practicable form of expansion gear in 1841; GEORGE H. CORLISS gave a new type of engine of marvelous perfection and economy in 1849; Noble T. Green, Wm. Wright and many less well known but no less meritorious inventors have since done their part in the transformation of the old engine of Watt into the modern wonder of concentrated and economical power, and marvel of accurate and beautiful design and workmanship. The "trip cut-off," with reduced clearances, increased boiler pressure, higher rates of expansion, accelerated speeds of engine, better construction in all respects, as well as improved design, have enabled us to avail ourselves to the utmost of the principles of Watt, and our mills, our railways, our steamers and our fields, even, have gained almost as extraordinarily by these advances, since the days of the great inventor, as through his immediate labors.

With the introduction of the new form of older energy, electricity, with the reduction of the lightning into thraldom, has now come a new impulse affecting all the industries. Through its mysterious, its still unknown action, steam now reaches out far from its own place, driving the electric car along miles of rail; giving light throughout all the country about it, turning night into day, and repressing crime while encouraging legitimate labor, reaching into distant chambers and every little workshop, to offer its powerful aid in all the distributed work of cities. Without the steam engine there would be little work available for electricity, but the appearance of this, the latest and most useful handmaid of steam, has given the engine work to do in an uncounted number of new fields, has called in the inventor once more to adapt steam to its new work. The "high-speed engine" is the latest form of the universal helper. And such has been the readiness and the intelligence of the contemporary inventor that we now have engines capable of turning their shafts three hundred rotations a minute and without a perceptible variation of velocity, whatever the change of load or the suddenness with which it is varied. In the days of Watt a fluctuation of five per cent. in speed was thought wonderfully small; in those of Corliss, the variation was restricted to two per cent. and we wondered at this unanticipated success. To-day, thanks to Porter and Allen, to Hartnell, to Hoadley, to Sims, to Thomson, to Sweet, to Ide, and to Ball, we have seen the speed fluctuation restricted to even less than one per cent. of its normal average.

The inventors of the steam engine are, through their representatives of to-day, according to the statisticians, doing the equivalent of twelve times the work of a horse, for every man, woman and child on the globe. We have not less, probably, than a half million of miles of railway, transporting something over 150,000,000,000 of tons a mile a year. A horse is reckoned to haul a ton weight about six and a half miles, day by day, by the year together. In the United States, it is reckoned that the steam engine, on the railways alone, hauls a thousand tons one mile, for every inhabitant of the country, every year, or, if it is preferred to so state it, a ton a thousand miles. This is the way in which the East and the West are, by the inventors of the steam engine, enabled to help each other. This costs about $10 each individual; it would require some 25 millions of horses to do the work, and would cost about $1,000 a family, which is more than twice the average family earnings.

Dr. Strong, in that remarkable book, "Our Country," says: "One man, by the aid of steam, is able to do the work which required two hundred and fifty men at the beginning of the century. The machinery of Massachusetts alone represents the labor of more than 100,000,000 men, as if one-half of all the workmen of the globe had engaged in her service." And again: "Some thirty years ago, the power of machinery in the mills of Great Britain was estimated to be equal to 600,000,000 men, or more than all the adults, male and female, of all mankind." Mr. Gladstone estimated that the aggregation of wealth on the globe during the whole period from the birth of Christ to that of Watt was equaled by the production in twenty years, at the middle of this century, with the aid of machinery driven by the fruit of the brain of the inventors of the steam engine. We may probably now safely estimate the former quantity as rivaled in less than five years, while, since the birth of Watt and his engine, and the production of the spinning mule, the power loom, the cotton gin and our own patent system and its marvelous mechanism, all events of a century ago, we may estimate that they have, together, accomplished more in this period which we now celebrate than could have been done in a millenium of milleniums without these now subjected genii. But the power behind all these curious inventions and their work is that of steam. The steam engine even supplies power to the telegraph and transports words and thought as well as cotton bales and coal.

And now what has this combination of legislation for private protection and public good, of a genius producing great inventions, and of the accumulated capital of earlier years, brought about?

It has given us the best fruits of science in permanent possession. The study of science invariably aids, in a thousand ways, the progress of mankind. It gives us new conceptions of nature and of the possibilities of art; it promotes right ways of work and of study; it teaches the inventor and the discoverer how most surely and promptly to gain their several ends, it gives the world the results of all acquired knowledge in concrete form. This one instance which we are now especially interested in contemplating has performed more wonderful miracles than ever Aladdin's genii attempted. One man, with a steam engine at his hand, turns the wheels of a great mill, drives forty thousand spindles, applies a thousand horse power to daily work in the spinning of threads, the weaving of cloth, the impulsion of a steamboat, or the drawing of great masses of hot iron into finest wire. This puny creature, his mind in his finger tips, exerts the power of ten thousand men, working with muscle alone, and, aided by a handful of women, boys and girls, clothes a city. A half dozen men in the engine room of an ocean steamer, with a hundred strong laborers in the boiler room and on deck, transports colonies and makes new nations, brings separated peoples together, unites countries on opposite sides of the globe, brings about easy exchanges between pole and equator. One man on the footboard of the locomotive, one man shoveling into the furnaces the black powder that incloses the energy stored in early geological ages, a half dozen men mounted on the long train of following vehicles, combine to bring to the mill girl in Massachusetts, the miner in Pennsylvania, the sewing woman, and the wealthy merchant, her neighbor in New York, the flour made in Minnesota from the grain harvested a few weeks earlier in Dakota. All the world is served faithfully and efficiently by this unimaginable power, this product of the brain of the inventor, protected by the law, stimulated and aided by the capital that it has itself almost alone produced.

And thus have the inventors of the steam engine set in motion and placed at the disposal of mankind for every form of useful work all the great forces of nature; thus Hero of Alexandria touched the then concealed spring which called all the genii of earth, fire, water and air to do the bidding of the race. Thus Papin, Worcester, Newcomen, Watt, and Corliss and others of our own contemporaries, have applied the genii to their task of leveling mountains, traversing seas, continents, and the depths of the earth, building ships, locomotives, hamlets and cities, cottages and palaces, turning the spindle, operating the loom, and setting motion and giving energy to every machine, doing the work of thousands of millions of men, converting barbarism into civilization, giving necessaries of life in profusion, comforts in plenty, and luxuries in superabundance.

Aiding and working hand in hand with those other genii of progress, the inventors of the printing press and of the telegraph, the telephone, and the electric railway, of the modern system of textile manufactures, of iron and steel making, of the mowing machine and the harvester, they have compressed into two centuries the progress of a millennium, destitute of their aid. Every step taken under their stimulus, and with their help, is a step toward a higher life for all, intellectually and morally as well as physically; every advance in the improvement of their work is a gain to every man, woman, and child; every improvement of the steam engine is a help to the whole world. This progress makes the day of the extinction of the system now grinding the populations of the earth into the ground, the day of the abolition of armies and the restoration to the people of that freedom which characterized the times of the patriarchs, and of the restoration of the rights of the citizen to his own time and strength and producing power, perceptibly nearer.

When this final revolution shall have been accomplished, and when all the world has settled down to the steady and undisturbed work of production by daily and regular labor, aided by the genii of steam, of electricity, of all nature, combined for good, the results of the intellectual activity of the inventors of the steam engine will be fully seen. Then no monument will be required to keep green the memory of Watt, Corliss, or any other of these great men, but it will be said of them, as of Sir Christopher Wren in the epitaph in St. Paul's: "Seek you a monument, look about you!" Every wreath of steam rising to the heavens from factory, mill or workshop will be a reminder of Hero of Alexandria, every mine will possess a memorial to Papin, Worcester and Savery; every steamship will bring into grateful memory Fitch and Stevens, and Bell and Fulton; thousands of locomotives, crossing the continents, will perpetuate the thought of the Stephensons and their colleagues in the introduction of the railway; the hum of millions of spindles and the music of the electric wire will tell of the work of Corliss and his contemporaries and successors who made these things possible, and all kingdoms and races, all nations, will revere the name of James Watt, the genius to whom the world is most indebted for the beginnings of all this later and grander civilization which has converted the slow progress of earlier centuries into the meteor-like advance of to-day toward a future as grand and as mighty and as noble as humanity shall choose to make it.

IMPROVED HAND CAR.

THE CONIC SECTIONS.