Chap. 8.]

Their first Engine.

465

and Newcomen had not lived. The spirit of inquiry that was abroad in their days, and the number of ingenious men engaged in devising means to employ steam as a motive agent, would assuredly have soon brought it into use. Indeed, every improvement in the application of steam seems to have been always perceived by some contemporary projectors, among whom the contest of maturing it was, as in a race, one of speed. "Watt [observes Prof. Renwick] found a competitor in Gainsborough, and but a few weeks would have placed Stevens on the very eminence where Fulton now stands." The circumstances of the times, the increase of English manufactures, and the general want of some substitute for animal labor, were all then favorable to the introduction of the steam-engine. "Had the mines of Cornwall been still wrought near the surface, Savery or Newcomen would hardly have found a vent for their engines. Had not the manufacturers of England been wanting in labor-saving machinery, the double-acting engine of Watt would have been suited to no useful application. A very few years earlier than the voyage of Fulton [to Albany] the Hudson could not have furnished trade or travel to support a steam boat, and the Mississippi was in possession of dispersed hordes of savages.'

No. 196. Newcomen and Cawley's Engine. A. D. 1705.

The above figure will sufficiently explain the principles and operation of Newcomen and Cawley's first engine; and, when compared with those

466

Condensation by Injection discovered by chance.

[Book IV. already noticed, will enable the reader to do justice to all concerned. It will be perceived that although steam is an essential agent, it is not the primum mobile of the apparatus: the pressure of the atmosphere is the first mover, and to excite this only was steam employed.

A, in the figure, (No. 196) represents a vibrating beam with arched ends or sectors, from one of which the main pump rod is suspended by a chain. This rod descends into the mine or pit, and is connected to as many other rods as there are pumps to be worked. A counterpoise or heavy weight m is fixed to the rod, so as to depress it and raise the other end of the beam in the position represented. a, the steam cylinder, open at top, its sides being surrounded by another, and the space between them containing water. r, the piston rod and piston, attached to the beam by a chain. b, the boiler. c, gauge cock. N, safety valve with weights. placed directly upon it. d, a cock to admit steam into the cylinder. e, a pipe and cock to convey the water round a, into the well or tank o. f, a pipe and cock to supply cold water to condense steam in the cylinder. h, another pipe and cock to furnish occasionally a little water to the upper side of the piston, to prevent air from passing between the packing and sides of the cylinder: this water was kept at the depth of about two inches. tt, a pipe proceeding from one of the pumps in the pit to supply the small cistern with water. P, a pipe to convey the steam condensed within a into the tank o. w the ash pit. xx, flues round the boiler.

Fire being applied to the boiler and steam generated, the cock dis opened and the cylinder filled with steam, provision being made for the escape of the air previously within. d is then closed and ƒ opened, by which cold water from the cistern is admitted to flow round a: this condenses the vapor within, and a vacuum being thus formed under the piston, the latter is pushed down by the atmosphere; consequently the opposite end of the beam is raised, and with it the pump rods and the load of water with which they are burthened. f is now closed and d again opened, when the counterpoise m preponderates, the piston is raised, the cylinder again filled with steam, and the operation repeated. But previous to the admission of vapor the second time into the cylinder, the cock f is closed and the one on pipe e opened, to allow the water between the cylinders to escape into the tank o, this water having become heated by its contact with a. As soon as the cylinder is charged anew with steam, a fresh supply of cold water to condense it is admitted by again opening f.

The amount of force thus excited depends upon the diameter of the cylinder a, or the area of its piston, and the state of the vacuum made under the latter. The dimensions of a must therefore be proportioned to the resistance to be overcome-to the quantity of water to be raised from a mine, and the height at which it is to be discharged-and to render an engine of the kind effective, the whole of the steam in a should be condensed, and as quickly as possible. These conditions were not very well fulfilled by the apparatus as figured above. Time was required for the cold water between the cylinders to extend its influence from the circumference to the centre of the inner one, in order completely to condense the vapor; hence the movements were extremely slow, the strokes seldom exceeding seven or eight per minute. An accidental circumstance pointed out the remedy, and greatly increased the effect. As the engine was at work, the attendants were one day surprised to see it make several strokes much quicker than usual; and upon searching for the cause, they found, says Desaguliers, "a hole in the piston which let the cold water [kept upon the piston to prevent the entrance of air at the packing] into the inside of the cylinder." The water falling through the steam condensed it al

Chap. 8.]

Savery claims a share in Newcomen's Patent.

467

most instantaneously, and produced a vacuum with far less water than when applied to the exterior of the cylinder. This led Newcomen to remove the outer cylinder, and to insert the lower end of the pipe ƒ into the bottom of a, so that on opening the cock f a jet of cold water was projected through the vapor. This beautiful device is the origin of the injection pipe still used in low-pressure engines.

Newcomen and Cawley's engine, as figured page 465, was improved in several parts in 1712, and soon after adopted as a hydraulic machine for draining the coal and iron mines in various parts of Europe. Very elaborate engravings of some used in French mines may be seen in the folio edition of Arts et Métiers. See also Desaguliers' Ex. Philos. vol. ii, and Switzer's Hydrostatics.

The application of sectors and chains to pump rods did not originate with Newcomen. They are figured by Moxon, and were probably employed in working pumps in mines previous to the invention of the steam-engine. We have often thought the heaviest charge against Savery was to be found in his conduct towards Newcomen and Cawley. Their machine was essentially different from his in its principle, construction and mode of action, yet he insisted that it was an infringement upon his patent. He employed the pressure of the atmosphere in charging his receivers, by condensing with cold water the steam within them. So far as regards this mode of forming a vacuum, (he in his receivers and they beneath a piston) there is a resemblance between the two machines, but no farther; and this plan of making a vacuum was not original with him any more than with them. It was no more a new device in his time than his paddle wheels were. The object of Newcomen and Cawley in forming a vacuum was also quite different from his; for they did not raise water into the vacuity, but employed it solely to excite the pressure of the atmosphere upon the upper side of a piston, in order to impart motion to common pump rods. Again, he used the expansive force of high steam: this was the prominent feature in his machine, and the great power that gave efficiency to it; but they did not use this power at all. The weight of the external air, not the expansive force of steam, was the primum mobile in their machine, and it was brought into action by the vapor of water at the ordinary boiling point.

But as they formed a vacuum in their cylinder by the condensation of steam, he insisted on having a share in their patent! The fact was his machines had become in a great measure laid aside, and he doubtless perceived that they were destined to be wholly superseded. Desaguliers (in 1744) observes that the progress and improvement of the fire engine were stopped by the difficulties and dangers attending it, till Newcomen and Cawley "brought it to the present form, in which it is now used, and has been near these thirty years." Unless his name was included as a joint patentee, Savery threatened an appeal to the law; and it is said his influence at court, as commissioner for the sick and wounded, gave weight to this ungenerous and unjust demand. Newcomen we are informed was a Quaker, or like Cawley a Baptist, and therefore on principle averse to legal controversy: he was moreover a man of “a great deal of modesty," and so yielded the point. The patent was consequently issued (in 1705) "to Thomas Newcomen and John Cawley of Dartmouth, and Thomas Savery of London."

Another point has been generally overlooked: far from Newcomen's machine being an infringement or improvement upon Savery's, it was really invented as early if not earlier than the latter. Switzer (Savery's friend) says, "it [Newcomen's engine] is indeed generally said to be an improve

468

Extensive adoption of Newcomen's Engine.

[Book IV. ment to Savery's engine, but I am well inform'd that Mr. Newcomen was as early in his invention, as Mr. Savery was in his, only the latter being nearer the court, had obtain'd his patent before the other knew of it; on which account Mr. Newcomen was glad to come in as a partner to it." (Hydrostatics, 342.) That is, as a partner to his own invention.

To Newcomen and his associate belongs the honor of laying the foundation for the modern engine. The piston engine of Worcester had been forgotten, Papin's was an abortion, and Savery probably never thought of one; hence, whether the Dartmouth mechanicians were aware of its previous employment or not, to them a large share of merit is justly due. They were moreover amiable and unassuming in their manners, and seem to have passed through life without exciting much of that envy that embitters more or less the nights and days of successful inventors. From such men, who can withhold expressions of approbation and esteem? Had they been members of the Roman church, they should have been canonized -could we believe in the efficacy of prayers for the dead, we would have masses performed for the repose of their spirits-and had we the power, every contributor to useful mechanism should be commemorated by an apotheosis.

Cawley died in 1717, but the date of Newcomen's decease has not been ascertained,

CHAPTER IX.

General adoption of Newcomen and Cawley's engine-Leopold's machine-Steam applied as a mover of general machinery-Wooden and granite boilers-Generating steam by the heat of the sun-FloatsGreen-houses and dwellings heated by steam-Cooking by steam-Explosive engines-Vapor enginesEnglish, French and American motive engines-Woisard's air machine-Vapor of mercury-Liquefied gases-Decomposition and recomposition of water.

Newcomen and Cawley's engines were found to answer the purpose of raising water so well, that in a few years they were introduced into Russia, Sweden, France and Hungary; and about 1760, one was imported by the proprietors of the old copper mine near Belleville, New Jersey. They in fact imparted a new and very beneficial impulse to mining operations, and quickly raised the value of mining stock. Deluged works were recovered, old mines deepened, and new ones opened, in various districts, both in Great Britain and continental Europe: nor were they confined to draining mines, but were employed to raise water for the use of towns and cities, and even to supply water-wheels of mills. By exciting the attention of ingenious men to their improvement, they became the means of extending manufactures generally, and introduced one which had never before been known in the world, viz. the fabrication of motive engines—a manufacture upon which the wealth, power and happiness of nations are destined in a great degree hereafter to depend.

Chap. 9.]

Leopold's Engine.

469

Leopold, to whom we have frequently referred, reflecting on Papin's experiments, suggested the following application of steam to move pistons and to raise water:

No. 197. Leopold's High Pressure Engine. A. D. 1720.

Two steam cylinders, open at top and provided with pistons a b, were placed over the boiler c, from the upper part of which a four-way cock d admitted steam alternately into the bottom of each. The pistons were connected by inflexible rods to the ends of two working beams, and to the opposite extremities of the beams were connected, by similar rods, the pistons f g of two forcing pumps, whose lower parts were placed in the water to be raised. An attendant turned the plug of the cock to admit steam under one piston, which was pushed up by the expansive force of the fluid, and consequently the piston of the pump connected to the same beam was forced down, and the water in its chamber driven up the rising main i. The cock was then turned to admit steam into the other cylinder, whose piston was raised in like manner; at the same time one passage of the cock opened a communication with the interior of the first cylinder and the external air, so as to allow the steam within to escape.-(See the figure.)

This is the first high-pressure piston engine figured in books. It has been greatly admired, and yet as represented it is useless and impracticable; for when the steam pistons were once raised the whole would remain immoveable, there being no means for causing them to descend. Had Leopold used one beam instead of two, and placed a pump and steam cylinder under each end, the device would have been complete and very effective.

It is singular that the researches of Leopold had not made him acquainted with the fact that four-way cocks were used long before Papin, to whom he attributes them.

With this device of Leopold, we take leave of steam machines. Hitherto they had been employed only to raise water, but the period was now approaching when the agency of this fluid as a first mover of machinery in general, was to become indefinitely extended. The engines of Newcomen