Part 4

Our story has now brought us to the early part of the eighteenth century. Everywhere men were now trying to make the most of the ideas of Worcester and Papin. The mines were growing very deep. As the water in them was getting beyond control something extraordinary had to be done. Now it seems that whenever the world is in need of an extraordinary service someone is found to render that service. The man who built the engine that was needed was a humble blacksmith of Dartmouth, England, Thomas Newcomen. This master mechanic in 1705 constructed the best steam-engine the world had yet seen. We must study Newcomen's engine (Fig. 7) very carefully. The large beam _ii_ moved freely up and down on the pivot _v_. One end of the beam was connected with the heavy pump-rod _k_ by means of a rope or chain working in a groove and the other end was connected with the rod _r_ in the same way. When steam from the boiler _b_ passed through the valve _d_ into the cylinder (steam-chest) _a_ it raised the piston _s_ and with it the piston-rod _r_ thus slackening the rope and allowing the opposite end of the beam to be pulled down by the weight of the pump-rod _k_. As soon as the piston _s_ reached the top of the cylinder the steam was shut off by means of the valve _d_ and the valve _f_ was turned and a jet of cold water from the tank _g_ was injected into the cylinder _a_ with the steam. The jet of cold water condensed the steam rapidly--steam is always condensed rapidly when anything cold comes in contact with it--and the water formed by the condensation escaped through the pipe _p_ into the tank _o_. As soon as the steam in _a_ is condensed, a vacuum was formed in the cylinder and the atmosphere above forced the piston down and at the same time pulled the pump-rod _k_ up and lifted water from the well or mine. When the piston reached the bottom of the cylinder the valve _d_ was opened and the piston again ascended. Thus the beam is made to go up and down and the pumping goes on. Notice that steam pushes the piston one way and the atmosphere pushes it back.

In Newcomen's engine the valves (_f_ and _d_) at first were opened and shut (at each stroke of the piston) by an attendant, usually a boy. In 1713 a boy named Humphrey Potter, in order to get some time for play, by means of strings and latches, caused the beam in its motion to open and shut the valves without human aid. We must not despise Humphrey because his purpose was to gain time for play. The purpose of almost all inventions is to save human labor so that men may have more time for amusement and rest. Humphrey Potter ought to be remembered not as a lazy boy but as a great inventor. His strings and latches improved the engine wonderfully (Fig. 8). Before his invention the piston made only six or eight strokes a minute; after the valves were made to open and shut by the motion of the beam, it made fifteen or sixteen strokes a minute and the engine did more than twice as much work.

Newcomen's engine as improved by Potter and others grew rapidly into favor. It was used most commonly to pump water out of the mines but it was put to other uses. In and about London it was used to supply water to large houses and in 1752 a flour mill near Bristol was driven by a steam-engine. In Holland Newcomen's engines were used to assist the wind-mills in draining lakes.

For nearly seventy-five years engines were everywhere built after the Newcomen pattern. Improvements in a small way were added now and then but no very important change was made until the latter part of the eighteenth century, when the steam-engine was made by James Watt practically what it is to-day. This great inventor spent years in making improvements upon Newcomen's engine (Fig. 9) and when his labors were finished he had done more for the steam-engine than any man who ever lived. We must try to learn _what_ he did. We can learn what Watt did by studying Figure 10. Here P is a piston working in a cylinder A _closed at both ends_. By the side of the cylinder is a _valve-chest_ C into which steam passes from the pipe T. Connecting C with the cylinder there are _two_ openings, one at the top of the cylinder and the other at the bottom. The valve-chest is provided with valves which are worked by means of the rod F, which moves up and down with the beam B, thanks to Humphrey Potter for the hint. The valves are so arranged that when steam enters the opening at the top of the cylinder it is shut off from the opening at the bottom, and when it enters the opening at the bottom it is shut off from the opening at the top. When the opening at the bottom is closed the steam will rush in at the upper opening and push the piston downward; when the piston has nearly reached the bottom of the cylinder the upper opening will be closed and steam will rush in at the bottom of the steam chest and push the piston upwards. Here was _one_ of the things done by Watt for the engine: he contrived to make the steam push the piston down as well as up. You have observed that in Newcomen's engine steam was used only to push the piston _up_, the atmosphere being relied upon to push it down. Thus we may say that Watt's engine was the first _real steam-engine_, for it was the first that was worked entirely by steam. All engines before it had been worked partly by steam and partly by air.

Watt's greatest improvement upon the steam-engine is yet to be mentioned. In Newcomen's engine when the cold water was injected into the cylinder it cooled the piston and when steam was let into the cylinder again a part of it, striking the cold piston, was condensed before it had time to do any work and the power of this part of the steam was lost. Watt did not allow the piston to get cold, for he did not inject any cold water into the cylinder. In his engine as soon as the steam did its work it was carried off through the pipe _M_ to the vessel _N_ and there condensed by means of a jet of water which was injected into _N_ (called the _condenser_) by means of a pump _E_ worked by the motion of the beam, thanks again to Humphrey Potter for the idea. This condensation of the steam outside of the cylinder and at a distance from it prevented the piston (and cylinder) from getting cold. In other words, in the Watt engine when steam entered the cylinder it went straight to work pushing the piston. No steam was lost and no power was lost and the cost of running the engine was greatly reduced.

It cannot be said that Watt invented the steam-engine--no one can claim that honor--yet he did so much to make it better that he well deserves the epitaph which is inscribed on his monument in Westminster Abbey. This inscription is as follows:

NOT TO PERPETUATE A NAME WHICH MUST ENDURE WHILE THE PEACEFUL ARTS FLOURISH BUT TO SHEW THAT MANKIND HAVE LEARNT TO HONOR THOSE WHO BEST DESERVE THEIR GRATITUDE THE KING HIS MINISTERS AND MANY OF THE NOBLES AND COMMONERS OF THE REALM RAISED THIS MONUMENT TO JAMES WATT WHO DIRECTING THE FORCE OF AN ORIGINAL GENIUS EARLY EXERCISED IN PHILOSOPHIC RESEARCH TO THE IMPROVEMENT OF THE STEAM ENGINE ENLARGED THE RESOURCES OF HIS COUNTRY INCREASED THE POWER OF MAN AND ROSE TO AN EMINENT PLACE AMONG THE MOST ILLUSTRIOUS FOLLOWERS OF SCIENCE AND THE REAL BENEFACTORS OF THE WORLD BORN AT GREENOCH MDCCXXXVI DIED AT HEATHFIELD IN STAFFORDSHIRE MDCCCXIX

But the story of the steam-engine does not end with Watt. It will be remembered that in the engines of Nero and of Branca the steam did its work by reaction or by impulse. Now soon after the time of Watt, inventors turned their thoughts to the old engines of Nero and Branca and began to experiment with engines that would do their work by a direct impact of steam. After nearly a century of experimenting and after many failures there was at last developed an engine known as the _steam-turbine_. In this engine the steam does its work by impinging or pushing directly upon blades (Fig. 11) which are connected with the shaft which is to be turned, and it does this in much the same manner that we saw the steam do its work in Branca's engine. One of the greatest names connected with the steam turbine is that of Charles Algernon Parsons of England. In 1884 this great inventor patented a steam-turbine which proved to be a commercial success and since that date the steam-turbine has been constantly growing in favor. So great has been its success on land and on sea that there are those who believe that the engine invented by Watt will in time be cast aside and that its place will be taken by an engine which is the most ancient as well as the most modern of steam motors.

THE PLOW

You have now learned the history of those inventions which enabled man to gain a mastery over fire and to use it for his comfort and convenience. We shall next learn the history of an invention which gave man the mastery of the soil and enabled him to take from the earth priceless treasures of fruit and grain. This invention was the plow.

In his earliest state man had no use for the plow because he did not look to the soil as a place from which he was to get his food. The first men were hunters and they relied upon the chase for their food. They roamed from place to place in pursuit of their prey--the birds and beasts of the forest and the fishes of the stream. They did not remain long enough in one spot to sow seed and to reap the harvest. Still in their wanderings they found wheat and barley growing wild and they ate of the seeds of these plants and learned that the little grains were good for food. They learned, too, that if the seeds were planted in a soil that was well stirred the plants would grow better than they would if the seeds were planted in hard ground. So by the time men had grown tired of wandering about and were ready to settle down and live in one spot they had learned two important facts: they knew they could add to their food supply by tilling the soil, and they knew that they could grow better crops if they would stir the soil before planting the seed.

For the stirring of the soil the primitive farmer doubtless first used a sharpened stick such as wandering tribes carry for the purpose of digging up eatable roots, knocking fruits down from trees, and breaking the heads of enemies. Such a stick known as the _Katta_ (Fig. 1) is carried by certain tribes in Australia, and we are told by travelers that the Kurubars of Southern India use a sharp stick when digging up the ground. The digging stick is used by savages in many parts of the world and we may regard it as the oldest of implements used for tilling the soil.

The first plow was a forked stick or a limb of a tree with a projecting point (Fig. 2). With this implement the ground was broken not by digging but by dragging the fork or projecting point of the stick through the ground and forming a continuous furrow. In this forked stick we see two of the principal parts of the modern plow. The fork of the stick is the _share_, or cutting part of the plow, while the main part of the stick is the _beam_.

An improvement upon the simple forked stick is seen in Figure 3, which is copied from an ancient monument in Syria (in Asia Minor). The old Syrian plow consists almost wholly of the natural crooks of a branch of a tree, the only artificial piece being the brace e which connects the share and the beam and holds them firm. In this crooked stick we have three of the main parts of the modern plow, the beam (a), the share (c-b) and the handle (d). The plow in this form requires the services of two persons--one to draw the plow and one to guide it and keep it in the ground. It is said that it was with a plow of this kind that the servants of Job were plowing when they were driven from their fields by the Sabeans.

The first plows were drawn by the strength of the human body (Fig. 4). Upon a very old monument of ancient Egypt, the country which seems to have been the first home of the plow, we have a plowing scene which shows a number of men dragging a plow by means of a rope. But primitive man was not at all fond of labor and in the course of time he tamed wild bulls and horses and made them draw the plows. So upon another Egyptian monument of a later date we have a picture of a plowing scene in which animals are drawing the plow (Fig. 5). In this Egyptian plow we see improvements upon the crooked stick of the Syrians. The Egyptian plow, you observe, has a broader share. It will, therefore, make a wider furrow and will plow more ground. Moreover, it has two handles instead of one. Taking it altogether, the Egyptian plow was a fairly good implement.

Many centuries passed before any real improvement was made upon the old Egyptian plow. If there were any improvement anywhere it was among the Romans. We read in Pliny--a Roman writer of the first century--of a plow that had wheels to regulate the depth of the plow and also a _coulter_, that is, a knife fixed in front of the share to make the first cut of the sod (Fig. 6). But such a plow was not in general use in Pliny's time. A thousand years later, however, the plow with wheels and coulter was doubtless in common use. In a picture taken from an old Saxon print we see (Fig. 7) a plow which was used in the time of William the Conqueror (1066). Here the plow has a coulter inserted in the beam and there are two wheels to regulate the depth to which the plow may go. This Saxon plow is drawn by four fine oxen and it is plainly a great improvement upon the old Egyptian plow.

But improvements in the plow during the dark ages came very slowly. At the time of the discovery of America the plow was still the clumsy wooden thing it was five hundred years before. In the sixteenth and seventeenth centuries, however, when improvements were being made in so many things, it was natural that men should begin to think of trying to improve the plow. In an old book published in 1652 we read of a double plow--one which would plow two furrows at one time. A picture (Fig. 8) of the double plow is given in the book but there is no proof that such a plow was ever made or ever used. The world did not as yet need a double plow, although the time was to come when it would need one.

In the early part of the eighteenth century we begin to see real improvements in plow making. About this time Dutch plowmakers began to put _mold-boards_ on their plows. The purpose of the mold-board is to lift up and turn over the slice of sod cut by the share. Without the mold-board the plow simply runs through the ground and stirs it up. With the mold-board of the Dutch plow (Fig. 9) the sod was turned completely over and the weeds and grass were covered up. This was the kind of plow that was needed, for if the weeds and grass are not covered up the best effects of plowing are lost. So the mold-board was a great improvement and its invention marks a great event in the history of the plow.

The Dutch plow was taken as a model for English plows and, in fact, for the plows of all nations. The mold-board grew rapidly into favor and by the end of the eighteenth century it was found on plows in all civilized nations. But the plow was still made mostly of wood (Fig. 10) and it was still an awkward and a poorly constructed affair. The method of making plows about the year 1800 has been described as follows: "A mold-board was hewed from a tree with the grain of the timber running as nearly along its shape as it could well be obtained. On to this mold-board, to prevent its wearing out too rapidly, were nailed the blade of an old hoe, thin strips of iron, or worn out horseshoes (Fig. 10). The land side was of wood, its base and sides shod with thin plates of iron. The share was of iron with a hardened steel point. The coulter was tolerably well made of iron. The beam was usually a straight stick. The handles, like the mold-board, were split from the crooked trunk of a tree or as often cut from its branches. The beam was set at any pitch that fancy might dictate, with the handles fastened on almost at right angles with it, thus leaving the plowman little control over his implement, which did its work in a very slow and most imperfect manner."

But about the end of the eighteenth century the world was beginning to need a plow that would do its work rapidly and well. Population was everywhere increasing and it was necessary to till more ground than had ever been tilled in former times. Especially was a good plow needed in the United States where there were vast areas of new ground to be broken. And it was in the United States that the first great improvements in the plow were made. Foremost among those who helped to make the plow a better implement was the statesman, Thomas Jefferson. This great man while traveling in France in 1788 was struck by the clumsiness of the plows used in that country. In his diary he wrote: "The awkward figure of their mold-board leads one to consider what should be its form." So Jefferson turned his attention to mold-boards. He saw that the mold-board ought to be so shaped that it would move through the ground and turn the sod with the least possible resistance and he planned for a mold-board of this kind. By 1793 he had determined what the proper form of a mold-board should be and had in actual use on his estate in Virginia several plows which had mold-boards of least resistance. Mr. Jefferson's patterns of the mold-board have, of course, been improved upon, but he has the honor of having invented the first mold-board that was constructed according to scientific and mathematical principles.[12]

About the time Jefferson was working upon the mold-board, Charles Newbold, a farmer of Burlington, New Jersey, was also doing great things for the improvement of the plow. We have seen that the plow of this time was a patch work of wood and iron. Newbold thought the plow ought to be made wholly of iron and about 1796 he made one of cast iron, the point, share, and mold-board all being cast in one piece. But the New Jersey farmers did not take kindly to the iron plow. They said that iron poisoned the crops and caused weeds to grow faster than ever. So Newbold could not sell his plows and he was compelled to give up the business in despair.

But soon the iron plow was to have its day. In 1819 Jethro Wood of Scipio, New York, took out a patent for a plow which was made of cast iron and which combined the best features of the plow as planned by Jefferson and by Newbold. In Wood's plow (Fig. 12) the several parts--the point, share and mold-board--were so fastened together that when one piece wore out it could easily be replaced by a new piece. In Newbold's plow when one part wore out the whole plow was rendered useless. Wood's plow became very popular and by 1825 it was rapidly driving out the half-wooden, half-iron plows of the olden time. Great improvements of course have been made upon the plow since 1819, but in the main features the best plows of to-day closely resemble the implement invented by Jethro Wood. Since our greatness as a nation is due largely to the plow all honor should be given to the memory of this inventor. "No citizen of the United States," said William H. Seward, "has conferred greater benefits on his country than Jethro Wood."

But the plow of Jethro Wood, as excellent as it was, did not fully meet the needs of the western farmer. The sod of the vast prairies could not be broken fast enough with a plow of a single share. So about the middle of the nineteenth century the _gang plow_, a hint for which had been given long before (p. 78) was invented, and as this new plow moved along three or four or five furrows were turned at once. At first the gang plow was drawn by horses (Fig. 13) but later it was drawn by steam (Fig. 14).

The great gang plow drawn by steam marked the last step in the development of the plow. The forked stick drawn by human hands and making its feeble scratch on the ground had grown until it had become a mighty machine drawn across the field by an unseen force and leaving in its wake a broad belt of deeply-plowed and well-broken soil.

FOOTNOTE:

[12] Daniel Webster was another great statesman who turned his attention to the making of plows. He planned a plow (Fig. 11) and had it made in his workshop on his farm at Marshfield. When the plow was ready for use, Webster himself was the first man to take hold of the handles and try it. The plow worked well and the great man is said to have been as much delighted with his achievement as he was with any of his triumphs in public life at Washington.

THE REAPER

After man had invented his rude plow and had learned how to till the soil and raise the grain, it became necessary for him to learn how to harvest his crop, how to gather the growing grain from the fields. The invention of the plow, therefore, must have soon been followed by the invention of the _reaper_.

The first grain was doubtless cut with the rude straight knives used by primitive man. In time it was found that if the knife were bent it would cut the grain better. So the first form of the reaper was a curved or bent knife known as the sickle or reaping hook (Fig. 1). The knife was fastened at one end to a stick which served as a handle. When using the sickle the harvester held the grain in one hand and cut it with the other. (Fig. 2).