Lectures on Popular and Scientific Subjects Part 2

_Printing_.--The spread of knowledge through the world is indeed a boon which cannot be too highly extolled; but the thoughts of man could not thus have been circulated had it not been for the printing-press. See what science and art have done for us in this most perfect and beautiful machine! When we go only to one example, the "Times" newspaper, and consider the amount of information it circulates each day through the world, it strikes one forcibly what man has been allowed and enabled to do for the benefit of himself and his fellow-men. What we have brought the printing-press to, is shown in 20,000 copies of the "Times" being thrown off in one hour, and the advantage it has been to the advancement of literature in our now being able to buy such works as those of Sir Walter Scott for sixpence a volume.

Having gone so far, I must not detain you for more than a brief period.

You have had such an able and interesting course of lectures given by men of high talent, that little remains for me except to close this course with congratulation to the a.s.sociation in being able to procure those individuals to give their valuable time to this desirable object; for what in life is more interesting than the imparting the knowledge we may possess to others who desire to acquire it, seeing that there is no way in which moral and social intercourse is more advanced and developed. Still, before closing, I must ask for a short time to go into one or two other subjects. And first, I will take one of the greatest importance to the commerce of this country, and one that has shown what the mind has done for communicating the thoughts of one person to another at far distant places--I refer to the telegraph. The land is not only covered with wires, but even the vast depths of the great ocean are made to minister to our requirements. The world, we may say, is encircled with ropes, and instant communication has been the result.

What has achieved these great results but the mind of man applied to science! And see in what a mult.i.tude of ways this application of mind has been made to work! What does it bring into play? Why, we have mining to produce the metal to make the wire; we have the furnace, hammers, and wire-drawing machines to produce the wire from the raw material. We have the forest then to go to for gutta-percha, for land poles, and for tar to preserve the cables. We have the farmer for our hemp. We have the chemist, we have the electrician, we have the steamer, and a great number of other requisites before the silent but unerring voice of the needle brings the thoughts of one man in America to another in this town in an instant of time. Accidents and mistakes will occur in the best-regulated works of all kinds, but I hope not often. One as to the telegraph I must tell that happened during the Indian Mutiny. The message meant to say that "The general won't act, and the troops have no head." The transformation was curious, namely, "The general won't eat, and the troops have cut off his head." If men would only consider well this grand achievement, they would be led indeed to say and feel, with all humility and thankfulness, that G.o.d has truly given him dominion over the works of His hands, and has put all things in subjection under his feet.

I had almost forgotten one other point of communication for mind, and, though at the risk of trying your patience, I must mention it, as its increase has been so large, and its advantages so manifold and untold. I mean the penny-postage. I am not going to enter into it at any length, but the increase of correspondence has been so large, that Sir Rowland Hill's name should not be left out of a lecture treating on subjects such as this one is intended to do. I will content myself by merely telling the increase of correspondence, and leave you to judge for yourselves as to its benefits. The number of letters in 1839, before the penny-postage, was 82,470,596, and in 1866 it was 597,277,616. Judge the difference!

Coming to the results of communication, I have one subject to bring before you, and as it has shown to such a large extent the benefits of international communication, I trust a few words on it may not be out of place. The subject is the great International Exhibitions that have been held in various countries in the last eighteen years. The first idea of holding such great exhibitions emanated from a man whose name cannot be held in too great estimation by all. Few men were gifted with such rare talents as he was, for there were few subjects, whether in science, literature, or art, that he was not intimately acquainted with.

This man was the late Prince Consort. He conceived the idea that if the products of the various countries of the world could be brought together under one roof, the knowledge these would convey of the machinery, cultivation, science, literature, and arts practised in the various parts of the globe would tend to stimulate and advance the mind by showing that we had not only ourselves to look to, but that in a great measure we had to depend on others for the many blessings we now enjoy; and also lead us to see how needful to our prosperity and comfort is a constant communication with those who can communicate to us that knowledge which otherwise we could not obtain. Certainly the results have proved that he was right. Could anything have been more interesting or instructive to all than a visit to the Great Exhibitions of 1851 or 1862, or that of Paris in 1867. The public interest is at once shown when I tell you that 6,039,195 persons visited the latter, and the receipts in money were 506,100. There, all and every one had before him at a glance the subject most suited to his taste, with a full description of the country which produced it. From the largest machine, the heaviest ordnance, the most brilliant and precious stones, the finest silks, lace, furniture, carriages, the greatest luxuries for the table, and, in fact, everything needful for the use of man;--all were there, and all to be seen and studied by the inquiring mind, or to be regarded as very wonderful by those who went to the Exhibition as a sight. Few, I venture to say, ever left these buildings except wiser than when they entered. It could not fail to strike one, if one only gave it a moment's reflection, and asked himself, how has all this been brought about, but that it was the result of the communication of the minds of certain individuals with those of others, and by a concentration of the products of various countries to enlighten the mind as to the vast intelligence of the world at large.

In conclusion, I feel now that I have spoken long enough for any lecture, though I have not by any means exhausted the subject of communication of either past or present; but I should feel grieved if I exhausted your patience. All things, as we well know, must have an end, except that life to which we are looking forward and striving to gain, where we shall cease from our labours and be at rest. We have been endued by our Maker with thought and mind, talents to be used for our benefit, and not wrapped up in a napkin till our Lord's return, but to be placed out so as to bring in either the five or the ten talents. And, as you all know, we are answerable for the manner in which we employ them. May the result prove that we have used them aright.

The progress of means of communication of mind and body have been gradual but steady, and I think may be represented by human life from its childhood to manhood, as beautifully set forth in the 13th chapter of 1st Corinthians 11th verse, where it is said, "When I was a child, I spake as a child; I understood as a child, I thought as a child; but when I became a man, I put away childish things." Is not this very much in keeping with our growth in communication? At first it was small, and we were content to hear of what others were engaged in without regard to time, as one day earlier or later was of little consequence. But now we are not children, but are become men in our interests and thirst for communication with each other. What should we say if we found the Express, as was written on the boy's post-bag, busily engaged in a game of bowls on the road, regardless of the loss of time or money thereby occasioned? I think we should be inclined to write to the papers.

The results of communication are manifold, and day by day they are brought before us in a manner which shows the untiring wish of man for improvement both in social and commercial interests. These results are strikingly shown in the various subjects I have endeavoured to bring before you. Each and all of them are subjects for thought. What should we now be without, I may say, any one of them?

A well-regulated mind is the most desirable of all acquirements, and I know no better means of gaining this than by meetings of such inst.i.tutions as this. Here you have intercourse with your friends, and you can gain from one another by friendly intercourse stores of knowledge, that to search for as individuals would take away much more time than you could by any means devote, and at the same time attend to the business of your calling. Here you have the means of amus.e.m.e.nt as well as of gaining sound information, and I trust no one here will ever have cause to regret the day when he came to a.s.sociate with his friends, and hear what others could communicate, for "in the mult.i.tude of counsellors there is wisdom."

_THE STEAM-ENGINE._

The many varieties of the world's manufactures--one might almost call them wonders--are now so numerous, that to bring any particular one in a single form before this meeting is a matter of no easy nature. To-night, however, I have ventured to single out, and have the pleasure of bringing before you, the steam-engine, as the prime mover at present of our workshops and manufactories, as also the grand motive power of our railways, now so different from the time when the great Stephenson was said to be mad, because he thought it possible to drive a train at fifteen miles an hour. For the first serviceable use of this grand machine we are indebted to the great James Watt. He it was who first wrought it so as to be under the useful and entire control of man, from what it was in the time of Hero of Alexandria, about 120 years before Christ. Our engineers have, since Watt's time, improved upon it year by year, till at the present day, instead of having to go in a mail-coach from London to Edinburgh, which formerly took fifty hours, we now go in the express train in ten, a distance of 420 miles. If beyond this ten hours, we grumble, and ask guards, porters, &c., at the various stations, "What has made the train so late to-day?" forgetting that just before the railways were first opened, the great Stephenson was urged not to say too much as to the supposed power of the locomotive, in case the cause of railways might be damaged. This was only some forty years ago, and it shows us how times are changed, for in the present day we consider thirty miles an hour anything but a fast train.

The history of the steam-engine is a subject on which so much has been written in books and magazines now before the public, that what I am about to offer, though pretending nothing new, yet I hope may be looked upon as containing something useful as well as instructive, both to the practical and the amateur mechanic. I shall therefore, in as small a compa.s.s as possible, trace the steam-engine from its first and early stages up to its present perfect state as our grand motive power. The first mention made of the vapour of water, as formed by the action of heat upon it, is found to be as far back as 120 B.C., when one Hero of Alexandria employed this vapour for the purpose of driving a machine. It is a well-known fact that when water is brought up to a certain degree of heat, called the boiling-point, that it sends forth a vapour, the elastic properties of which, when in an open vessel, are not perceived--as, for instance, in a common pan--yet if the vessel is closed or shut up at the top, you will find that the vapour acquires such a degree of elastic force, that, if not allowed to escape by fair means, it would soon make a way or vent for itself by bursting whatever vessel it was contained in. Steam is thus highly elastic, but when separated from the fluid out of which it is generated, it does not possess a greater elastic force than the same quant.i.ty of air. If, for example, a vessel is filled with steam only at 212, it may be brought to a red heat without fear of bursting; but if water is also in the vessel, each additional quant.i.ty of heat causes a fresh quant.i.ty of steam to be generated, which adds its elastic force to that of the steam already in the vessel, till the constantly acc.u.mulating force at last bursts the vessel.

This elastic vapour is called steam, and it is by this that that most beautiful machine, the steam-engine, is driven. As you all know, by this vapour or air--for it is invisible till it loses part of its heat--enormous power is obtained in a small compa.s.s, and the labour of man reduced to nothing compared with former ages. Many men laboured to perfect machinery to be worked by this vapour of water, and many came near the mark; but it remained for the great Watt, at the Soho Works, Birmingham, to bring the engine to its useful and working state, for though discovered as a motive power 120 B.C., it was yet reserved for this truly great man to be what may be termed the inventor of the steam-engine.

In 120 B.C., Hero of Alexandria made a machine to be driven by steam. It consisted of a hollow sphere into which the steam was admitted; projecting from the sphere were two arms, from which the steam escaped by three holes on the side of _each_ arm opposite to that of the direction of its revolution, which, by removing the power from off the one part of _each_ arm, caused it to revolve in the direction opposite to that of the hole that allowed the steam to escape. This kind of engine has been for some years in use by Mr. Ruthven of Edinburgh. There are others who have followed very closely on Hero's plan in more ways than one; for instance, it is the common Barker's mill, though with this difference, that his mill is driven by water instead of steam: Avery, also, made a steam-engine almost exactly the same. I may here, perhaps, just be allowed to mention what a little water and coal will produce, as it will show at once from whence our power is derived. "A pint of water may be evaporated by two ounces of coal; in its evaporation it swells to 216 gallons of steam, with a mechanical force equal to raising a weight of thirty-seven tons one foot high." A pound of coal in a locomotive will evaporate about five pints of water, and in their evaporation these will exert a force equal to drawing two tons on a railway a distance of one mile in two minutes. A train of eighty tons weight will take 240 pa.s.sengers and luggage from Liverpool to Birmingham and back, each journey about four and a quarter hours; this double journey of 190 miles being effected by the combustion of one and a half tons of c.o.ke, worth about twenty-four shillings. To perform the same work by common road would require twenty coaches, and an establishment of 3800 horses, with which the journey would be performed each way in about twelve hours, stoppages included. So much for the advantages of steam.

The Romans are supposed to have had some knowledge of the power of steam. Among amusing anecdotes, showing the knowledge the ancients had of steam, it is told that Anthemius, the architect of Saint Sophia, lived next door to Zeno. There existed a feud between them, and to annoy his neighbour, Anthemius had some boilers placed in his house containing water, with a flexible tube which he could pa.s.s through a hole in the wall under the floor of Zeno's dwelling; he then lit a fire, which soon caused steam to pa.s.s through the tube in such a quant.i.ty as to make the floors to heave as if by an earthquake. But to return. We next come to Blasco de Garay (A.D. 1543), who proposed to propel a ship by the power of steam. So much cold water seems to have been thrown on his engine, that it must have condensed all his steam, as little notice is taken of it except that he got no encouragement. We find that it has also been used by some of the ancients in connection with their deities.

Rusterich, one of the Teutonic G.o.ds, which was found in an excavation, proves how the priests deceived the people. The head of this one was made of metal and contained a pot of water. The mouth and another hole in the forehead being stopped by wooden plugs, a fire of charcoal was lighted under this pot of water, and at length the steam drove out the plugs with a great noise, and the G.o.d was shrouded in a mist of steam which concealed him from his astonished worshippers.

In 1629, Giovanni Branca of Loretto in Italy, an engineer and architect, proposed to work mills and other machinery by steam blowing against vanes, much in the same way as water does in turning a wheel. The waste of steam in such a plan is so obvious, that it is not to be wondered at that it did not produce any great results, as we all know that the moment we let steam out of his case, the case is all up with him, and he dies a natural death. He is a most delicate yet powerful agent, and requires to be kept warm in all weathers--this fact does not seem to have struck Mons. Branca when he let him out of his boiler.

The next person we come to, and perhaps the first of any note, is the Marquis of Worcester in 1663 (died 1667). He was a man who seems, as far as history tells us, to have taken a great interest in furthering the advancement of steam. He was not contented with one invention, but published a book ent.i.tled "A Century of Inventions," and in this work he describes a means of raising water by the pressure of steam. The Marquis appears to have been a politician as well as an inventor, as we find he was engaged on the side of the Royalists in the Civil Wars of the Revolution, lost his fortune and went to Ireland, where he was imprisoned. Escaping to France, from thence he returned to London as a secret agent of Charles II., but was detected and imprisoned in the Tower, where he remained till the Restoration, when he was set at liberty. One day, while in prison, he observed the lid of the pot in which his dinner was being prepared lifted up by the vapour of the water boiling inside. Reflecting on this, he turned his mind to the matter, and thought that this vapour, if rightly applied, might be made a useful moving power. He thus describes his invention in his 68th Article: "I have contrived an admirable way to drive up water by fire, not by drawing or sucking it upwards, thirty-two feet. But this way hath no bounds, if the vessels be strong enough." He then goes on to say, that "having a way to make his vessels, so that they are strengthened by the force within, I have seen the water run like a constant stream forty feet high. One vessel rarified by fire driveth forty of cold water, and one being consumed, another begins to force, and refill with cold water, and so on successively, the fire being kept constant. The engineman having only to turn two c.o.c.ks, so as to connect the steam with the one or the other vessel."

In this engine, if it can be called an engine, we see that the Marquis had a good idea of the power of steam, but he had none, you will observe, as to the action of the condensation which would immediately take place when the steam from the boiler was brought into contact with the cold water to be raised. Therefore this plan would be most expensive, on account of the great loss of steam by condensation. It was, however, quite able to produce the effect, though only equal to raising 20 cubic feet of water, or 1250 lbs., one foot high by one pound of coal, or about the two-hundredth part of the effect of a good steam-engine. After this, of course, it proved of no avail; but still we may say that the Marquis of Worcester was among the first who tried to make, and did do so, steam a moving power.

Our next is Denys Papin (died 1710), a native of Blois, in France, who was mathematical professor at Marpurg. To him is due the discovery of one of the qualities of steam--its condensation, so as to produce a vacuum, to the proper management of which our modern engines owe much of their efficacy. Papin seems to have been the first who conserved the idea of the cylinder and piston, which he made to act on atmospheric principles--that is to say, he took a cylinder with a piston moving up and down in it, and found that by removing the air from under the piston in the cylinder, that the pressure of the atmosphere would drive it down to the bottom of the cylinder: this he performed by admitting steam, and then condensing it rapidly, so causing the required vacuum. The pressure of the atmosphere is as near as may be 16 lbs. on every square inch of surface on the globe: this is obviously the weight of the columns of air extending from that square inch of surface upwards to the top of the atmosphere. This force is thus measured: Take a gla.s.s tube 32 inches long, open at one end and closed at the other; provide also a basin full of mercury; let the tube be filled with mercury and inverted into the basin. The mercury will then fall in the tube, till it gets to that height which the atmosphere will sustain. This is nothing more than the barometer used in all our houses. If the action of the tube be equal to a square inch, the weight of the column of mercury in the tube would be exactly equal to the weight of the atmosphere on each square inch of surface. Thus Papin discovered a great step in the steam-engine, though it was not much acted on for some years; he was also the first who proposed to drive ships with paddles worked by steam.

We now come to Thomas Savory, who got a patent in 1698 for a method of condensing steam to form a vacuum. Savory describes his discovery in this way:--Having drank a flask of wine at a tavern, he flung the empty flask on the fire, and then called for a basin of water to wash his hands. A little wine remained in the flask, which of course soon boiled, and it occurred to him to try what effect would be produced by putting the mouth of the flask into the cold water. He did this, and in a moment the cold water rushed up and filled the flask, this being caused by the steam being condensed and leaving a vacuum, which Nature abhors, and rather than permit this the water rushed up and took the place formerly occupied by the now condensed steam. We see by this in how simple a way great ends are produced, and in the age in which this happened, the result may be indeed be said to have produced a great end.

The engine of Savory was used for some years as a machine to raise water. The principle of his engine was just as I have stated, and consisted of two cases and other various parts, and this engine possessed advantages over that of the Marquis of Worcester in sucking up the water as well as forcing.

Savory's engine consisted of two steam vessels connected to a boiler by tubes; a suction pipe, or that pipe which leads from a pump of the present day to the well, and communicating with each of the steam vessels by valves opening upwards; a pipe going from these steam vessels to any required height to which the water is to be raised. The steam vessels were connected to this pipe by other valves, also opening upwards, and by pipes. Over the steam vessels was placed a cistern, which was kept filled with _cold_ water. From this proceeded a pipe with a stopc.o.c.k. This cistern was termed the condensing cistern, and the pipe could be brought over each steam vessel alternately from the boiler.

Now, suppose the tubes to be filled with common air, and the regulator placed so that one tube and the boiler are made to communicate, and the other tube and the boiler closed, steam will fill one of the steam vessels through one tube; at first it will condense quickly, but erelong the heat of the steam will impart its heat to the metal of the vessel, and it will cease to condense. Mixed with the heated air, it will acquire a greater force than the air outside the valve, which it will force open, and drive out the mixture of air and steam, till all the air will have pa.s.sed from the vessel, and nothing but the vapour of water remain. This done, a c.o.c.k is opened, and the water from the cistern is allowed to flow over the outside of the steam vessel, first having stopped the further supply of steam from it; this produced the immediate condensation of the steam contained in it, by the temperature being brought down again by the cold water, and the condensation thus produced caused a vacuum inside the vessel. The valve will then be kept closed by the atmosphere outside, and the pressure of the air on the surface of the water in the well or reservoir will open another valve, force the water up the pipe, till, after one or two exhaustions--if I may so term it--it will at last reach the second vessel. Thus far the atmosphere has done all the work, but at last the water fills the vessel, and then comes the forcing point. Now the power of the steam itself is used to drive the water up the pipe. The steam is again let into the vessel, now filled in whole, or at least in great part, with water; at first it will, as before, condense rapidly, but soon the surface of the water will get heated, and as hot water is lighter than cold, it will keep on the surface, and the pressure of the steam from the boiler will drive all the water from the vessel up the pipe. When it is empty the c.o.c.k is again opened, and the steam, which the vessel by this time only contains, is again condensed, and the same process which I have just described is again commenced and carried out, thus making Savory's engine a complete pump by the aid of the vapour of water as raised by fire.

Savory had the honour of showing this engine to His Majesty William III.

at Hampton Court Palace, and to the Royal Society. He proposed the following uses, which perhaps may as well be mentioned, as they show how little was then known of the real value of the power of steam:--1. To raise water to drive mill-wheels--fancy erecting a steam engine now, of say fifty horse-power, to raise water to turn a wheel of say thirty; 2.

To supply palaces and houses with water; 3. Towns with water; 4.

Draining marshes; 5. Ships; 6. Draining mines. There is one more thing I may mention as curious, that though the steam he used must have been of a high pressure, he did not use a safety-valve, though it had been invented about the year 1681 by Papin. The consumption of fuel was enormous in Savory's engine, as may easily be perceived from the great loss of steam by condensation. Nevertheless, it was on the whole a good and a workable engine, as we find the following said of it by Mr.

Farey:--"When comparison is made between Captain Savory's engine and those of his predecessors, the result will be favourable to him as an inventor and practical engineer. All the details of his invention are made out in a masterly style, so as to make it a real workable engine.

His predecessors, the Marquis of Worcester, Sir S. Morland, Papin, and others, only produced outlines which required to be filled up to make them workable."

I must not detain you much longer before I proceed to the great Watt, but I will just name Newcomen, who invented an engine with a cylinder, and introduced a beam, to the other end of which he fixed a pump rod like a common or garden pump. He made the weight of the pump and beam to lift the piston, and then let the steam enter below the piston and condensed it by a jet of water, thus causing a vacuum, when the pressure of the atmosphere drove the piston from the top to the bottom of the cylinder and lifted the pump rods in the usual way. There were various c.o.c.ks to be opened and shut in the working of this engine for the right admission of steam and water at the required moments, a task which was performed by boys who were termed c.o.c.k-boys. I will now mention an instance which, though in practice not to be imitated, yet was one of those happy accidents which sometimes turn out for the best. One of these boys, like many, more fond of play than work, got tired of turning these c.o.c.ks day by day, and conceived the idea of making the engine do it for itself. This idle boy--we will not call him good-for-nothing, as he proved good for a great deal in one way--was named Humphrey Potter, and one day he fixed strings to the beam, which opened and shut the valves, and so allowed him to play, little thinking this was one of the greatest boons he could possibly have bestowed on the world at large, for by so doing he rendered the steam-engine a self-acting machine.

We now come to a period which was destined to advance the cause of steam to a far greater extent--in fact, the time which rendered the steam-engine the useful and valuable machine it now is. This is the time of James Watt. This great man, be it said to the credit of Scotland, was born in Greenock, on the Clyde, on the 19th January 1736. His grandfather was a farmer in Aberdeenshire, and was killed in one of the battles of Montrose. His father was a teacher of mathematics, and was latterly chief magistrate of Greenock. James Watt, the celebrated man of whom I now speak, was a very delicate boy, so much so, that he had to leave school on account of his health, and was allowed to amuse himself as he liked. This he did in a scientific way, however, as an aunt of his said to him one day: "Do you know what you have been doing? You have taken off and put on the lid of the teapot repeatedly; you have been holding spoons and saucers over the steam, and trying to catch the drops of water formed on them by it. Is it not a shame so to waste your time?"

Mrs. Muirhead, his aunt, was little aware that this was the first experiment in the way which afterwards immortalised her nephew.

In 1775 Watt was sent to London to a mathematical instrument maker, but could not stay on account of his health, and soon afterwards came back to Glasgow. He then got rooms in the College, and was made mathematical instrument maker to the University, and he afterwards opened a shop in the town. He was but twenty-one years of age when he was appointed to this post in the College, and his shop became the lounge of the clever and the scientific. The first time that his attention was directed to the agency of steam as a power was in 1734, when a friend of his, Mr.

Robinson, who had some idea of steam carriages, consulted him on the subject,--little is said of this, however. In 1762 Watt tried some experiments on high-pressure steam, and made a model to show how motion could be obtained from that power; but did not pursue his experiments on account of the supposed danger of such pressure. He next had a model of Newcomen's engine, which would not work well, sent him to repair. Watt soon found out its faults, and made it work as it should do. This did not satisfy him, and setting his active mind to work, he found in the model that the steam which raised the piston had of course to be got rid of. This, as a natural consequence, caused great loss of heat, as the cylinder had to be cooled so as to condense the steam; and this led him at last, after various plans, to adopt a separate vessel to condense this steam. Of course, if you wish to save fuel, it is necessary that the steam should enter a heated cylinder or other vessel, or else all the steam is lost,--or in other words, condensed,--that enters it, until it has from its own heat imparted so much to the cylinder as to raise it to its own temperature, when it will no longer condense, and not till then does it begin to exert its elastic power to produce motion. This was the great object gained by James Watt, when, after various experiments, he gave up the idea altogether of condensing steam in its own or working cylinder, and then made use of a separate vessel, now called the condenser.

The weight of steam is about 1800 times less than water. I may here perhaps mention also that water will boil at 100 degrees Fahr. in vacuo, whereas in atmosphere it takes 212 degrees to boil. There is also a thing perhaps worth knowing to all who wish to get the most stock out of bones, &c., that if they are boiled in a closed vessel, that is to say, under a pressure of steam, a very large increase in quant.i.ty of the stock will be produced, because the heat is increased. A cubic inch of water, evaporated under _ordinary_ atmospheric pressure, will be converted into a cubic foot of steam; and a cubic inch of water, evaporated as above, gives a mechanical force equal to raising about a ton a foot high.

The next great improvement of Watt, in addition to the condenser, is the air-pump, the use and absolute necessity for which you will understand when I explain its action. Watt first used it for his atmospheric engine. The piston of this engine was kept tight by a flow of oil and water on the top, which tended to make the whole a troublesome and bad-working machine. The cold atmosphere, as the piston went down, of course followed it and cooled the cylinder. On the piston again rising, some steam would of course be condensed and cause waste. If the engine-room could be kept at the heat of boiling water, this would not have been the case, but the engineman who could live in this heat would also require to be invented, and so this had to be given up. Watt's next and most important step was the one which brings us to talk of the steam-engine as it now is in the present day. This important step was the idea, of making the steam draw down the piston, as well as help to drive it up; in the first engines it was raised by the beam, and steam used only to cause a vacuum, so as to let the air drive it down. All before this had been merely steps in advance, like those of children, who must walk before they can run; so was it with the steam-engine. It was uphill work for many years, and the top of the hill cannot be said to have been readied till Watt worked out this grand idea. The first engine could only be called atmospheric; now it was destined to become in reality a steam-engine. Time would fail were I to attempt to go into any details of all the experiments through which Watt toiled to bring his ideas to perfection--enough to say that he did so; and I trust you will be able, through the description I will endeavour to give, to understand how well his labour was bestowed, and how beautiful the result has proved for the benefit of the world at large. In 1773, Watt removed to Soho, near Birmingham, where a part of the works was allotted to him to erect the machinery necessary to carry out his inventions on a grand scale.

We must now proceed to some of the useful points of the engine, all I have before mentioned simply relating to the inventors and improvers; but having brought it so far, I may now, I think, proceed further. The first use of the steam-engine was simply to raise water from mines, and for long it was thought it could be used for nothing else; so much so, that it was at one time used to raise water to turn wheels and thus produce motion. One of its first uses after it became a really useful machine was to propel ships, though many a weary hour was spent to bring it to this point. There is a very pretty monument on the Clyde, dedicated to Mr. Bell, who I believe was the first person who successfully brought steamers to work on its waters. The first who used steam for ships was Mr. James Taylor, in conjunction with Mr. Miller of Dalswinton. The danger of the fire-ship took such hold on people's minds that it was with great toil and difficulty they were persuaded to venture on the face of the waters in such dangerous and unseamanlike craft. But go to Glasgow Bridge any day, and you will see how time has overcome fear and prejudice, for our ocean is covered with steamers of all sizes. It is not many years ago since it was said that steamers could never reach America; this has given way to proof, and even Australia has been reached by steam. I know of a steamer building which could carry the whole population of this place and not be full; she is 680 feet or 226 yards long, and a large vessel would hang like a boat alongside her.

The first attempt at giving motion by steam to ships was of course only in one way--by a ratchet at the end of a beam, at one moment driving and the next standing still. This was on account of the engine being only in power one half of the stroke; but by the double-acting engine being introduced, and the steam acting both ways, it became at last a steady mover (without the aid of two or three cylinders, as in the first engines, one to take up the other as the power was given off), by a ratchet on the end of a beam or else a chain. This acted on the shaft which moved the paddles. It is to Watt that we are indebted for the crank and direct action, so as to give a circular motion to the wheels.

We find in 1752 a Mr. Champion of Bristol applied the atmospheric engine to raise water to drive a number of wheels for working machinery in a bra.s.swork, in other words, a foundry. Also, in Colebrokedale, steam-engines were used to raise water that had pa.s.sed over the wheel, so as to save water. All these plans have, however, now pa.s.sed by, like the water over the wheel, and we now have the engine the prime mover--the double action of the steam on the piston, this acting on the sway beam, and the beam on the crank, which, by the a.s.sistance of the fly-wheel on land or fixed engines, gives a uniform motion to the machine. All these have now enabled us to apply the engine as our grand moving power. One great and important point in the engine is the governor, and the first modes of changing the steam from the top to the bottom of the cylinder were c.u.mbrous, till the excentric wheel was devised.

Boilers also have to be attended to--these were at first rude and now would be useless. They were unprovided with valves, gauge-c.o.c.ks, or any other safety, all of which are now so well understood that nothing but carelessness can cause a blow-up. One of the greatest causes of danger is that of letting there be too little water in the boiler, and thus allowing it to get red-hot, when, if you let in water, such a volume of steam is generated that no valve will let it escape fast enough. Force or feed pumps are also required to keep the water in the boiler at a proper height, which is ascertained by the gauge-c.o.c.ks. Mercury gauges for low pressure act according to the pressure of the atmosphere; high-pressure boilers of course require a different construction, as the steam is greater in pressure than the air.

Having got so far in my subject, I think before concluding I must devote a short time in showing the first steps of the locomotive; the more so, as I am speaking to those who are so largely engaged in the daily working of that now beautifully perfect machine. Various and for a time unsuccessful experiments were made to bring out a machinery or travelling engine, as it was first called. A patent was taken by a Mr.

Trevethick for a locomotive to run on common roads, and to a certain extent it did work. An amusing anecdote is told of it. In coming up to a toll-gate, the gatekeeper, almost frightened out of his seven senses, opened the gate wide for the monster, as he thought, and on being asked what was to pay, said "Na-na-na-na!" "What have we got to pay?" was again asked. "No-noth-nothing to pay, my dear Mr. Devil; do drive on as fast as you can!" This, one of the first steam carriages, reached London in safety, and was exhibited in the square where the large station of the London and North-Western Railway now stands. Sir Humphrey Davy took great interest in it, and, in writing to a friend, said: "I shall hope soon to see English roads the haunts of Captain Trevethick's dragons."

The badness of roads, however, prevented its coming into general use.

Trevethick in 1804 constructed a locomotive for the Merthyr and Tydvil Rail in South Wales, which succeeded in drawing ten tons at five miles an hour. The boiler was of cast-iron, with a one-cylinder engine, spur gear and a fly-wheel on one side. He sent the waste steam into the chimney, and by this means was very nearly arriving at the blast-pipe, afterwards the great and important discovery of George Stephenson. The jumping motion on the bad roads, however, caused it constantly to be dismounted, and it was given up as a practical failure, being sent to work a large pump at a mine. Trevethick was satisfied with a few experiments, and then gave it up for what he thought more profitable speculations, and no further advances were made in locomotives for some years. An imaginary difficulty seems to have been among the obstacles to its progress. This was the supposition that if a heavy weight were to be drawn, the grip or bite of the wheels would not be sufficient, but that they would turn round and leave the engines stationary, hence Trevethick made his wheels with cogs, which of course tended to cause great jolts, as well as being destructive to the cast-iron rails.

A Mr. Blenkinsop of Leeds patented in 1811 a locomotive with a racked or toothed rail. It was supported on four wheels, but they did not drive the engine; its two cylinders were connected to one wheel behind, which was toothed and worked in the cog-rail, and so drove the engine. It began running on Middleton Coal Rail to Leeds, three and a quarter miles, on the 12th August 1812, and continued a great curiosity to strangers for some years. In 1816 the Grand Duke Nicholas of Russia saw this engine working with great interest and expressions of no slight admiration. An engine then took thirty coal-waggons at three and a quarter miles in an hour.

We next come to Messrs. Chapman of Newcastle, who in 1812 tried to overcome the supposed want of adhesion by a chain fixed at the ends of the line and wound round a grooved drum driven by the engine. It was tried on the Heaton Rail near Newcastle, but was found to be so clumsy that it was soon abandoned. The next was a remarkable contrivance--a mechanical traveller to go on legs. It never got beyond its experimental state, and unfortunately blew up, killing several people. All these plans show how lively an interest was then being taken in endeavouring to bring out a good working locomotive. Mr. Blackett, however, persevered hard to perfect a railway system, and to work it by locomotives. The Wylam waggon-way, one of the oldest in the North, was made of wooden rails down to 1807, and went to the shipping-place for coals on the Tyne. Each chaldron-waggon was originally drawn by a horse with a man in charge, only making two journeys in the one day and three on the following, the man being allowed sevenpence for each journey.

This primitive railway pa.s.sed before the cottage where George Stephenson was born, and was consequently one of the first sights his infant eyes beheld; and little did his parents think what their child was destined to work out in his day for the advancement of railways. Mr. Blackett took up the wood and laid an iron plate-way in 1808, and in 1812 he ordered an engine on Trevetbick's principle. It was a very awkward one, had only one cylinder of six inches diameter, with a fly-wheel; the boiler was cast-iron, and was described by the man who had charge of it as having lots of pumps, cog-wheels, and plugs. It was placed on a wooden frame with four wheels, and had a barrel of water on another carriage to serve as a tender. It was at last got on the road, but would not move an inch, and her driver says:--"She flew all to pieces, and it was the biggest wonder we were not all blown up." Mr. Blackett persevered, and had another engine, which did its work much better, though it often broke down, till at length the workmen declared it a perfect plague. A good story is told of this engine by a traveller, who, not knowing of its existence, said, after an encounter with the Newcastle monster working its great piston, like a huge arm, up and down, and throwing out smoke and fire, that he had just "encountered a terrible deevil on the Hight Street road."

We now come to George Stephenson, who did for the locomotive what Watt did for our other steam-engines. His first engine had two vertical cylinders of eight inches diameter and two-feet stroke, working by cross-heads; the power was given off by spur-wheels; it had no springs, consequently it jolted very much on the then bad railways; the wheels were all smooth, as Stephenson was sure the adhesion would be sufficient. It began work on the 25th July 1814, went up a gradient of one in 450, and took eight waggons with 30 tons at four miles an hour.

It was by far the most successful engine that had yet been made. The next and most valuable improvement of Stephenson was the blast-pipe--by its means the slow combustion of the fire was at once overcome, and steam obtained to any amount. This pipe was the result of careful observation and great thought. His next engine had horizontal connecting rods, and was the type of the present perfect machine. This truly great man did not rest here, but time would fail, as well as your patience, if I were to proceed further. Enough to say, that he afterwards established a manufactory at Newcastle, and time has shown the result and benefit it has proved to the whole world at large. A short time before the Liverpool and Manchester Railway was opened, Stephenson was laughed at because he said he thought he could go thirty miles an hour, and was urged before the House of Commons not to say so, as he might be thought to be mad. This I have from person who knew the circ.u.mstances.

Nevertheless, at the trial, I believe the "Rocket" did go at the rate of thirty miles an hour, to the not small astonishment of the world, and especially to the unbelievers in steam as a land agent. The stipulation made was that trains were to be conveyed at the rate of twelve miles an hour.

In our present perfect engines, the c.o.ke or fuel consumed per mile is about 18 lbs. with a train of 100 tons gross weight, carrying 250 pa.s.sengers. A first-cla.s.s carriage weighs 6 tons 10 cwts.; a second-cla.s.s, 5 tons 10 cwts., each with pa.s.sengers; a Pullman car weighs about 30 tons. Our steamers consume 5 lbs. of coal per horse-power in one hour. And last, not least, one of the greatest improvements we have had in steam propulsion is the screw. Again, I may also name the great advantage derived from steam by our farmers in thrashing out grain. The engines princ.i.p.ally used in farm-work are what are termed high-pressure, or of the same cla.s.s as the locomotive. The great saving in cost in the first place, the simplicity and ease of action in the second, and the small quant.i.ty of water required to keep them in action, are all reasons why they should be preferred. The danger in the one, that is, the high-pressure, over the condenser, is very small, and all that is required is common care to guard against accidents. Steam being a steady power, is much to be preferred to water, as by its constant and uniform action the tear and wear of machinery is much diminished, and of course proportionate saving made in keeping up the mill or any other machinery.

Having now, to the best of my power, so far as a single lecture will permit, brought the steam-engine from 120 B.C. to the present time, it only remains for me to say, that it shows how actively the mind of man has been permitted to work to bring it to perfection by the direction of an all-wise Providence, "who knows our necessities before we ask, and our ignorance in asking." A traveller by rail sees but little of the vast and difficult character of the works over which he is carried with such ease and comfort. Time is his great object. No age of the world has conquered such difficulties as our engineers have had to deal with, and the result is now before the eye of every thinking traveller. Our engineers were at first self-taught, and many a self-taught man has had reason to rejoice in the time he spent in his education. Of these men we have examples in Brindley, who was at first a labourer and afterwards a millwright; Telford was a stone-mason; Rennie a farmer's son apprenticed to a millwright; and George Stephenson was a brakesman at a colliery.

Perseverance with genius, and a determination to overcome, made them the great men they were. That you may so persevere and strive is the earnest wish of him who has this evening had the great pleasure of giving you this lecture, and who feels so greatly obliged to you for the very patient hearing you have given him.