The Life of Sir William Fairbairn, Bart
Chapter II - Mechanical Engineering

In the list of occupations of the civil engineer, given at the end of the preceding chapter, the three last, referring to the design and manufacture of engines and machinery, and of structures in iron, constitute what is now considered a special branch of the profession, called mechanical engineering. The number of mechanical engineers is very large, many being men of high attainments; and the late Sir William Fairbairn was one of the most esteemed of them. On this account it becomes desirable to give some special notice of the peculiarities of this branch of the profession, with which, in the following pages, we shall have more particularly to do.

An acquaintance with the art of working in metals has always been considered one of the signs of dawning civilisation, and machinery of some kind for the simplest wants of life, such as raising water, grinding corn, and so on, must have been in use in the earliest ages. But a few centuries before the Christian era we come upon a great man who is undoubtedly entitled to be called the father of mechanical engineers, namely, Archimedes of Syracuse. lie combined great theoretical knowledge of geometry and other sciences with singular inventive and constructive skill, and his mechanical contrivances have acquired for him a lasting renown.

After hi« day, many mechanical constructions were in use which derived their origin from his discoveries, as, for example, the clepsydras or water clocks of Egypt, which are said to have first contained that now universal element of machinery, the toothed wheel. Hero, about 250 B.C., wrote treatises describing various mechanical contrivances; and the erection, about the same time, of the great Colossus of Ehodcs, showed much power in metal work.

The Romans largely used mechanical appliances.

The celebrated Soman writer on architecture, Vitruvius (b.c. 50), enumerates earlier writers on machinery, and enters fully into the mechanical principles and arrangements applicable to constructive purposes. He mentions an officer called a machinarius, who had charge of machines, and who was, in fact, the mechanical engineer of the rime.

We know also that in these ages mills worked by-water power were in use for grinding corn, and these must have involved some complexity and ingenuity of design.

After the revival of learning in Europe the mathematical and mechanical sciences began to be more cultivated, and practical mechanics became a favourite study with ingenious men. Many works are extant which show this; among them one by Agricola (Georg Land mann), in Germany, who died in 1555; another by Jacques Besson, in France, 1573; and a third, better known, entitled ' Diversi ed artificiose Macchine,' by Capitano Agostino Eamelli, published in 1588.

The curious work ' Les raisons des forces mouvantes, avec diverses machines taut utiles que plaisantes, par Salomon de Caus, Ingenieur et Architecte du Roy,' originally published in 1615, is celebrated as containing tolerably clear notions about the nature and power of steam. The Marquis of Worcester's well known ' Century of Inventions,' published in 1659, may also be mentioned ; as well as the splendid work of Belidor of 1737-53, ' Architecture Hydraulique,' already alluded to, which contains copious descriptions of the hydraulic, machine known in his (lay.

In England, before the eighteenth century, the most important articles of machinery, such as windmills, water mills, &c., were brought from the continent, principally from the Low Countries. The celebrated pumping apparatus fixed at London Bridge in 1582, for supplying London with water, was erected by Peter Morice, a Dutchman.

As, however, such contrivances became more used, a class of native artificers sprang up, who made it their business to attend to them. They were called millwrights. They designed and erected windmills and water mills for grinding corn, pumping apparatus, and all the various kinds of rough machinery in use in those days.

It is probable these men were the first who, as a civil class, devoted themselves specially and exclusively to engineering work. They were therefore the earliest civil engineers, and their successors have descended to the present day in an unbroken line as practitioners in the mechanical branch of civil engineering.

Mr. Fairbairn, who was educated strictly as a millwright, and was never ashamed of calling himself by that name, gives the following account of this class of men:—

The term millwright has long been a household word, and at no distant period conveyed the idea of a man marked by everything that was ingenious and skilful.

The millwright of former days was to a great extent the sole representative of mechanical art, and was looked upon as the authority on all the applications of wind and water, under whatever conditions they were to be used, as a motive power for the purposes of manufacture. He was the engineer of the district in which he lived, a kind of Jack-of-all-trades, who could with equal facility work at the lathe, the anvil, or the carpenters bench. In country districts, far removed from towns, he had to exercise all these professions, and he thus gained the character of an ingenious, roving, rollicking blade, able to turn his hand to anything, and like other wandering tribes in days of old, went about the country from mill to mill, with the old song of 'kettles to mend,' re-applied to the more important fractures of machinery.

Thus the millwright of the last century was an itinerant engineer and mechanic of high reputation. In the practice of his profession he had mainly to depend on his own resources. Generally, he was a fair arithmetician, knew something of geometry, levelling, and mensuration, and in some cases possessed a very competent knowledge of practical mathematics.

He could calculate the velocities, strength, and power of machines ; could draw in plan and section, and could construct buildings, conduits, or watercourses, in all the forms and under all the conditions required iu his professional practice.

His attainments as a mechanic and his standing in the useful arts, were, however, apt to make him vain, and with a rude independence he would repudiate the idea of working with an inferior craftsman or even with another as skilful as himself, unless he was 'born and bred a millwright.'

Such was the character and condition of the men who designed and carried out most of the mechanical work of this country up to the middle and end of the last century.

I have deemed it necessary to give this brief account of the habits and character of a body of men whose skill and spirit of perseverance have done so much for the advancement of applied science, and whose labours have had a large, influence on the industrial progress of the country. I am perhaps better qualified for this task than most others, from having been associated with them from early life, so that an experience of some fifty years must be my excuse for having imposed this narrative upon the reader.

It is significant that the first Englishman, after Hugh Myddelton, who distinguished himself in the more general practice, Brindley, was properly and originally one of this class. lie was apprenticed to a wheelwright and millwright, and afterwards worked on his own account in the same trade. lie erected corn mills, paper mills, silk mills, pottery mills, and engines generally. It was his success in these things that caused him to be first employed or: canals, and his mechanical skill and experience stood him in good stead in many ways during their construction.

Smeaton, though not a millwright by trade, had great aptitude for mechanical construction, and was well versed in mechanical science. His paper on Wind and Water Mills, which gained him the gold medal of the Royal Society in 1759, was an admirable and useful essay, founded on many years' experiments, and is still referred to as of high authority. His published reports show that he was largely engaged oil mechanical engineering, as they refer to the construction of steam-engines, waterworks, pumps, boring machines, corn and oil mills, forges, and other machinery of various kinds.

It was about Smeaton's time that mechanical engineering took an enormous step in advance by the improvements which were effected in the manufacture of iron; and m explanation of this great element of the question it is necessary to say something here of the history of the iron manufacture.

The two great properties of iron, fusibility and malleability, which enable it to be either cast into shape by melting or worked into shape by hammering (thus forming what are now called cast and wrought iron work respectively) appear to have been known at an early period. In the thirteenth century nails, horse-shoes, and other wrought articles were largely supplied from Sussex, and cast cannon were founded there in the sixteenth century. The manufacture in this district reached its height towards the close of the reign of Elizabeth, when the trade became so prosperous that England began to export iron in considerable quantities. It gradually fell off, however, by the failure of the wood fuel employed; one of the last extensive contracts executed there being the casting, about 1700, of the iron rails which enclose St. Paul's Cathedral.

In 1620 the first step of the modern iron manufacture was taken, in the invention by Dud Dudley of iron smelting by coal. The inventor set up works in the midland counties, where he made in this way both malleable iron and castings; and in the civil wars occurring in the middle of the century he not only supplied the king with iron war implements and stores, but followed the army and acted as a military engineer.

"Whether it was from the inferior quality of Dudley's iron, from prejudice against it, or from difficulties in the working, his system does not seem to have made immediate way; for the iron manufacture declined rather than advanced until the beginning of the eighteenth century, when Abraham Darby, a mechanic and millwright of Bristol, introduced from Holland a new method of making iron castings, chiefly hollow ware for domestic use, by moulding them in line dry sand. He established, in 1700, iron works at Colebrook Dale in Shropshire, and his casting trade there was successful. At first he used charcoal for fuel, but coal being plentiful in the neighbourhood, he adopted it by previously making it into coke, and at a later period—about 1760—the coal was used raw.

In 1766 another great improvement was made by producing malleable iron, with pit coal as fuel, in a reverberatory furnace, it having previously been produced on a 'refinery' hearth with charcoal. This was the invention of two foremen at Colebrook Dale, named Cranege, and was carried out by Richard Reynolds, the manager there at the time.

By the exertions and enterprise of three generations of Darbys the Colebrook Dale works had become greatly enlarged, and had widely extended their operations; they had formed establishments in London, Bristol, and Liverpool, and had erected workshops for the manufacture of machinery generally, many of the atmospheric, or Newcomb's steam-engines being made there, to be used in mines in various parts of the kingdom. The Darbys were the first to substitute, ir. 1767, iron for wooden rails in the tram roads along which coal and iron were conveyed from one part of the works to the other, thus initiating the modern system of iron railways.

The Colebrook Dale works have also the credit of having erected the first iron structure of any magnitude, namely, a cast-iron arch bridge of large span. Some proposals and attempts at using iron for bridges had been previously made, but the material was prohibited by the great cost and even impossibility of obtaining it in sufficiently large masses.

Abraham Darby the third, when he entered the business as a young man, saw the necessity of forming a communication between the steep banks of the river Severn, to accommodate the large population which had sprung up on both sides. Emboldened by his improvements in iron manufacture, he designed an iron arch of 100 feet span, which was cast at the works, and was opened for traffic in 1779. It still stands as firm as ever, and Mr. Robert Stephenson said of it: ' If we consider that the manipulation of cast iron was then completely in its infancy, a bridge of such dimensions was doubtless a bold as well as an original undertaking, and the efficiency of the details is worthy of the boldness of the conception.'

After the successful example of Colebrook Dale, other iron works became established in different parts of the country, particularly in Staffordshire, Wales, and Scotland.

In 1783 a man named Peter Onions, working in the Welsh district, made a valuable improvement in the manufacture of malleable iron, by combining with the reverberatory furnace (introduced by the Craneges some years before) the peculiar process called 'puddling,' which has since been the universal mode employed.

At the same date some very important improvements were introduced by Henry Cort. In the course of his business as a navy agent or contractor, he had occasion to see the inferiority of English malleable iron to that imported from Russia and Sweden; he entered on a series of experiments with a view to its improvement, and he; took out two patents in 1783 and 1781. They related in the first place to the mode of producing the malleable iron from the pig, and, secondly, to the mode of giving it certain merchantable forms.

In regard to the first of these, lie adopted the reverberatory puddling furnace of Cranege and Onions, and does not seem to have added to it any novel feature of striking originality; but he so altered and improved the details of working as to produce a very much better quality of iron.

His other invention was more original. In the first place he took advantage of the welding power of malleable iron, when in a highly heated state, in order to form masses of larger size than had been previously made. He piled several pieces together, heated the whole in a furnace to a white heat, and then subjected the pile to the blows of a heavy hammer, whereby it became welded and consolidated into one integral mass, which could be forged into any shape desired, as to make anchors and so on. ISut having a view to the more general usefulness of malleable iron in the shape of long parallel bars, he proposed to make these by forming his piles of a long shape, and effecting the consolidation, not by hammering but by passing the piles through grooved rollers, so that, using successively grooves diminishing in size, the iron could be drawn into long bars of any dimensions required.

It was one of Cort's objects, that by the force of the hammering or the pressure of the roll-drawing, not only should the iron be welded and consolidated, but the dross, scoria, or 'slag' should be thoroughly squeezed out, and the iron generally made purer and of better quality.

The processes described by Cort have been followed by iron manufacturers, with but slight modifications, to the present time. After the lapse of nearly a century the modes of manufacturing bar from cast iron, arid of puddling, piling, hammering, and rolling, are all nearly identical with the descriptions he gave.

Cort expended a fortune of upwards of 20,000/. in perfecting his inventions, but he was robbed of the fruit of his discoveries by the villainy of officials in a high department of government, and he was ultimately left to starve. Mr. Fairbaim, as we shall see in a future chapter, took up warmly the cause of some of his descendants, and by great exertions succeeded in getting something done for them.

In 1759 the Carron Ironworks were established by Dr. Roebuck and others, on an excellent site, surrounded with coal and ironstone, near Falkirk in Scotland. Soon afterwards their mechanical arrangements were taken in band by John Smeaton, who by many ingenious alterations and improvements enabled the proprietors to manufacture cast-iron of a much better quality than before. Smeaton took advantage of this by introducing the use of iron more largely into machinery and mechanical constructions generally. Formerly, the staple material of the millwright had been wood, iron being only used in small pieces, chiefly for binding the woodwork together. Smeaton saw the immense advantage it would be to make the parts more extensively of iron, and he was now enabled by the improvements at Carron to do this, applying the material to many new uses.

The first cast-iron axis for a water wheel was made there in 1769, and iron cog-wheels and shafts of all dimensions gradually followed, although the use of the new material was yet uncertain, and failures were not unfrequent. The well-known carronades, or light cast-iron guns, so long used in the navy, took their name from the Carron Works, where they were originally made;.

We now arrive at the date of the great improvements in the steam-engine effected by James Watt.

About 1710 Newcomen had invented the earliest really efficient form of steam prime mover, then called a fire-engine, and subsequently many of these had been erected for the purpose of raising water in the mines of Cornwall and elsewhere. Brindley, in the course of his millwright's practice, had paid some attention to them, and Smeaton had also much improved their construction, and had, shortly after 1770, erected some that were pronounced the best in existence. The cylinders of the early engines were made of brass, which caused them to be very expensive, but as the manufacture of cast-iron improved, Smeaton substituted this metal with great advantage.

Watt took out his patent for the separate condenser in 1709, but he saw, with a truly practical eye, that he could make no progress with his machines till he could ensure their proper manufacture. With this view, finding the Carron Works promising well, he associated himself with Dr. Roebuck, proposing to establish his manufactory there. But while Watt was contending with his first difficulties of construction, Dr. Roebuck became embarrassed, and in 1773 sold his share of the patent to Mr. Matthew Boulton, of Soho.

The works at this place had been built about 1705, for the general manufacture of various kinds of Birmingham hardware, and Watt was so well pleased with the manner in which their mechanical arrangements had been carried out, that he desired nothing better than to find a home there for his own inventions. Fortunately his wish was gratified, and the Boulton and Watt partnership ensured the fulfilment of his most sanguine plans. His first successful engine was made in 1774, and soon afterwards, the merits of the invention being at once recognised, it came into extensive application.

For some years, however, the new engines were adapted exclusively to rectilinear motion for pumping water, the great field for their employment being the mines of Cornwall. The important change which enabled them to produce rotary motion was not perfected till about 1784, and this is therefore the date when the great grime mover which has since worked such wonders may be said to have really come into existence.

One of the first made was for the Albion Mills, a large establishment erected for grinding corn on the south bank of the Thames, a little to the east of Blackfriars Bridge. In the design and construction of the machinery for this mill Mr. Watt was assisted by a young man, afterwards known as one of the most eminent English engineers, John Rennie. This youth had learnt mechanics under a clever millwright, Andrew Meikle, the inventor of the threshing-machine, and had acquired such a good reputation that Watt entrusted to him a large share of the work.

The mill was not only novel in its motive power, but the machinery was on a larger scale and of a more advanced character than anything of the kind before constructed. The use of cast-iron was carried farther than had been done by Smeaton, and with better results, as the experience at Soho had been greater. The parts were more accurately formed, and their strengths better determined.

This first example of modern millwork was set to work in 1788. It proved a great success, and measures were in progress for the extension of the mill, when it was unfortunately burnt to the ground in March 1791.

After the ruins were cleared away Mr. Rennie bought a piece of the land, on which he set up a manufactory for engines and machinery; and it was here that Mr. Fairbairn had his interview with him described in the fifth chapter. The manufacturing business, on Mr. Rennie's death, passed into the hands of his sons, and is still carried on, on the original site of the Albion Mills, by his grandsons, George and John Rennie.

During the century that has elapsed since Watt began his career, mechanical engineering has been ever advancing with rapid and gigantic strides. Every new application of power has stimulated industry and commerce, and this has reacted in calling for extended exertions on the part of the mechanical engineer. It would be vain to attempt here to enumerate the wonderful results achieved in this way; but we may dwell for a little on the advances made, since Watt's time, in the production of iron, and in the processes for applying it to the purposes of mechanical engineering.

The production of iron has immensely extended. One cause of this has been the introduction, by James Beaumont Neilson, iu 1828, of the hot blast, which has rendered available a class of minerals and substances formerly useless. It has, in fact (as Mr. Fairbairn has remarked), effected an entire revolution in the iron industry of Great Britain.

The iron-producing districts mentioned in a former part of this chapter, namely, the midland counties, Wales, and Scotland, have enormously developed, the latter being greatly extended by the discovery, in 1801, by David Mushet, of the ' Black Band' ironstone.

In addition to these, other districts liav4 been made available for iron production, the most important being the great iron fields of Cleveland, in the north-east of England. The ironworks established within the last few years in the valleys of the rivers Tees and Wear have an extent and magnitude quite surprising, considering the suddenness with which the industry has sprung up in the neighbourhood.

Another large seat of iron manufacture, also very recent, is on the opposite or north-western coast, at Barrow-iu-Furness, in Lancashire, where large works have sprung up for the utilisation of a particular kind of ore, the red hematite, found plentifully there.

In the neighbourhood of Leeds, at Low Moor and elsewhere, large works have also been built, chiefly with the object of making iron of particularly fine quality; and in many other parts of the country where ore has been found, works for its conversion have come into existence.

The most recent novelty has been the introduction of certain new processes for the production of the higher classes of the material in a way more direct than formerly. The best known of these is what is called the Bessemer process, by which a metal having the qualities of malleable iron is produced by fusion. The metal has been found to possess certain advantages which have acquired for it a large consumption, and the effect has been to stimulate its manufacture on a corresponding scale.

As an illustration of the increase of iron production, the following figures may be given, partly taken from Sir William Fairbairn's book:—

The Quantity of Iron annually produced in Great Britain;—

Since this last date it has declined, and is now probably about 6,000,000 tons.

We have now to speak of the various processes and appliances necessary for working up this material, and for bringing it- into the shape and condition required to form machinery and iron structures. The improvements made in this respect during the last century have been most extensive and important.

When Watt began to carry his improvements into practice he was terribly hampered and delayed by the difficulty he found in getting his work made with the necessary accuracy. 'The machine projected,' says Mr. Smiles, ' was so much in advance of the mechanical capability of the age, that it was with the greatest difficulty it could be executed. When labouring at his invention at Glasgow, he was baffled and thrown into despair by the clumsiness and incompetency of his workmen. Even after he had removed to Birmingham, and he had the assistance of Boulton's best workmen, Smeaton (no bad judge of the state of mechanics in his time) expressed the opinion when he saw the engine at work, that notwithstanding the excellence of the invention, it could never be brought into use because of the difficulty of getting its various parts manufactured with sufficient precision. Nearly everything had to be done by hand. The tools used were of a very imperfect kind. A few ill-constructed lathes, with some drills and boting machines of a rude sort, constituted the principal furniture of the workshop.'

Watt endeavoured to remedy the defect by keeping certain sets of workmen to special classes of work, and allowing them to do nothing else. Fathers were induced to bring up their sons at the same bench with themselves, and initiate them in the dexterity which they had acquired by experience: and at Soho it was not unusual for the same precise line of work to be followed by members of the same family for three generations.

Lu this way as great a degree of accuracy was arrived at as was practicable under the circumstances ; but, notwithstanding all this care, accurate fitting could not be secured so long as the manufacture was conducted mainly by hand, and hence arose gradual improvements in too Mi chiefly with the view of making them act automatically. By this means not only was their capability greatly increased, but far greater precision was attained than could ever have been ensured by manual labour1. The facilities thus afforded led to a constant progressive improvement in the character of the work done, at the same time constantly diminishing the dependence on mere manual skill.

The manufacturing processes by which works iu iron are constructed may be classed under four great heads— founding, forging, riveting, and shaping ; the latter including operations of many kinds.

Founding, or the manufacture of articles in cast-iron, is still pretty much as it was left by Abraham Darby. An impression of the object is moulded in sand, and this is filled with molten iron. All since done has been confined to details for improved accuracy and facility in moulding, and the formation of larger and sounder castings by peculiar modes of preparing the mould.

In malleable iron the manufacture of articles by the operation of forging received a great impulse about 1840, through the invention, by James Nasmyth, of the steam hammer. The power of men in wielding hammers was always limited; and although huge hammers moved by steam were hi use for the purpose of iron production, their action was too rough to admit of the formation of accurate shapes, and hence the use of forgings in machinery was much restricted. Nasrnyth's apparatus, while it enabled the most powerful blows to be giverr, provided for their regulation and application with the greatest nicety of adjustment, aud this at once brought the stronger, tougher, and more trustworthy material into use, for cases of a magnitude and variety unknown before. The gigantic wrought iron stem and stern posts of iron ships, the huge shafts and axles of engines, and the monster wrought-iron guns lately produced, owe their existence entirely to the steam hammer; and by means of dies, fashioned in a proper way, small articles of peculiar shape can be forged with facility and certainty.

Other ingenious machines have been introduced for forging bolts, nuts, rivets, and other small articles of large consumption, much facilitating and cheapening their production.

Riveting is a very useful process by which iron ships, boilers, tanks, and the most ordinary kinds of iron bridges are formed from malleable iron plates of small thickness. Holes being punched or drilled in corresponding positions in the edges of two plates, these are placed over each other, red-hot rivets are passed through and clenched over, and thus a strong union is formed. This process is a very old one, but it has been much improved by Fairbairn's invention of the riveting-machine, of which a notice will be found in a subsequent chapter.

We may next consider the processes necessary to bring pieces of ironwork, either cast or wrought, into the true shapes they are intended for, with the view cither of ensuring their perfect mechanical action, or causing them to fit firmly and closely together. In this shaping we may distinguish four kinds of operations; namely, turning, boring, planing, and general shaping. Each requires tools of a special nature, and all have received much attention.

Turning is the most important operation, on account of the great predominance of parts of machinery which are of a circular or a cylindrical shape, or otherwise symmetrical round an axis. The great tool for this purpose— the lathe—has been in use from time immemorial, and in even engineer's shop the lathe is largely employed. This principle of the lathe is still what it was thousands of years ago; the article to be turned being caused to revolve about an axis, while a cutter is applied to its exterior, and caused slowly to move or slide so as to produce the desired profile.

There has been, however, a great improvement introduced in the slide rest—a very simple but beautiful contrivance—by which the cutter, instead of being held and guided by the hand of the workman, is attached to a holding-frame or rest, which is made to move or slide, either by a handscrew, or automatically by the same power which turns the lathe. The effect of this is not only to save skilled labour, but to give much more accuracy to the work, as well as the power of producing with the greatest ease effects which, by mere hand motion, would be scarcely possible.

This invaluable addition to the lathe was invented by Henry Maudslay, one of the men to whom mechanical engineering is largely indebted for its modern advancement. Originally a smith, he afterwards went to the shops of Joseph Brainah (the inventor of the hydraulic press, the Iiramah lock, the water-closet apparatus, and many other ingenious things), where, about 1794, he first introduced the improvement in question. In 1810, he founded the celebrated engineering establishment in Lambeth, still carried on by the firm of Maudslay, Sons and Field.

The lathe has received a vast variety of ingenious additions for the purpose of executing fine complicated ornamental turning; but as used for large purposes in engineering work, it remains in nearly its simplest form, with the addition of the slide rest, and some improvements by Joseph Clement to equalise its action. It has, however, been given gigantic dimensions and great power for work of large size, and the most delicate accuracy for small uses.

Boring is an operation analogous to turning, but, so to speak, reversed, as it is in this case an interior surface, instead of an exterior one, which has to be made true. The cylinder of a steam-engine is one of the best examples of this kind of work. It is made of cast-iron; but it is necessary that its interior surface should be made accurately cylindrical and perfectly true and smooth, so that the piston may slide easily up and down, at the same time fitting perfectly tight in all positions, to prevent waste of steam and loss of power. This accuracy must be given by the operation of boring.

It was in this particular that Watt found the greatest difficulty, for his machine required greater accuracy than it had been necessary to give to the old fire-engines. His early cylinders were made at the Carron Works, where Smeaton had put up a machine for boring cannon, but they were so untrue that they were next to useless. The pistons could not be kept steam-tight, notwithstanding the various expedients of stuffing with cork, putty, chewed paper, and greased old hat. Watt complained, in regard to one of eighteen inches diameter, that it was so far from circularity, that ' at the worst place the long diameter exceeded the short by three-eighths of an inch!'

The defect of the ordinary boring apparatus was that it was fixed from one end only of the cylinder, as if boring a gun (for which purpose the machine was indeed originally made), and hence was not sufficiently stable in position to guide the tool accurately in its heavy work of cutting the interior surface. The first efficient boring-machine was contrived, about 1775, by a founder and millwright at Chester, named John Wilkinson. He conceived the happy idea of putting a strong bar completely through the cylinder, and fixing it firmly at both ends on lathe centres. Hence when this bar, being provided with proper cutters, was caused to rotate by the ordinary lathe motion, great power could be brought on the cutters without endangering their steadiness of position in regard to the axis. The ' boring bar,' as it was termed, has since been the universal tool for such work, having been, like Maudslay's lathe, made automatic, and given other improvements in detail.

Planing differs fix unturning and boring, inasmuch as it requires the metal to be operated on in right lines instead of curves, so as to form plane surfaces perfectly flat and true. It is, in fact, analogous to the well-known operation of the same name in woodwork, where a tool carrying a cutter is driven along by the workman's arm, shaving down the surface of the wood till the requisite smoothness is obtained.

Down to a late period no operation at all analogous to the planing of wood was practised with iron; for although a good steel tool could be made to cut iron with the aid of a lathe, it was beyond the power of a man to make such a tool take a shaving off iron in a right line. The usual mode of getting plane surfaces was by what was called ' chipping and filing.' The iron was first brought to something like a level form by chipping little bits off it with a steel chisel, and it was afterwards worked down by large files till a smooth surface was gained. It need hardly be said that such a plan was very laborious and troublesome, and also very likely to be inaccurate.

At length, as tools improved, it seems to have occurred to machinists that it would be possible to construct a sliding frame strong enough to hold and guide a cutting tool ;n a rectilinear path, so as to make it cut a shaving off a piece of iron underneath; and then, by repeating these cuts, to form the plane surface required. The thing was done, and so arose the planing-machine, a tool of the greatest utility.

The invention of the planing-machine has been claimed for several eminent mechanics. It is probable that, as the apparatus required considerable contrivance to make it successful, it grew up under several hands, but it is certain that a large share of the credit is due to a man named Joseph Clement. lie was, like Maudslay, a workman of Brainah's, who afterwards went into business for himself as a mechanical engineer on a small scale, and was greatly celebrated for his ingenuity and mechanical skill, particularly in regard to the construction of tools, lie was the only person to be found who could make the extremely accurate work required for Mr. Babbage's Calculating Engine. lie made a planing-machine before 1820, and afterwards established a larger machine which for many years was the only good thing of the kind in existence. He allowed it to be used on hire by other engineers, and it brought him a considerable income.

The planing-machine is now extensively used, and of such size as to plane very large surfaces. It is one of the most indispensable tools in a large engineering factory, and its value in promoting accuracy of work has been very great. It is made in two forms: either the article to be planed is fixed, and the tool traverses backwards and forwards over it; or the tool is fixed, and the article is made to move underneath it. It is very customary to make the tool reverse after the forward stroke, so as to present its cutting edge in the other direction, and cut also on the return stroke, by which time is saved. In either case an arrangement is added by which the line of the cuts is caused to advance automatically by a small distance at every cut, so as to cover at length the whole surface to be planed.

The planing-machine being once established, its principle was soon carried out more generally in what are called shaping and slotting machines. These are smaller but not less useful instruments, in which a cutter moving in a reciprocating line like that of a planing-machine, but in a path of only a few inches long, can be made to cut away portions of a piece of ironwork in any direction. If the exterior of the article is offered to the tool, it is shaped by the metal being cut away; or, by bringing the cutter to bear upon a hole already formed by casting or drilling, the hole can be enlarged and given a square or oblong form, or transformed into what is called a slot, whence one of the names of the machine.

The article to be shaped or slotted is placed on a movable frame, and made to advance automatically, and by altering its position great varieties of shapes can be produced.

These shaping and slotting machines are used in large numbers in good shops, and contribute essentially to accuracy and good finish of engineering work.

There are many minor but very useful improvements in engineering tools which are worthy of mention.

The mode of making screws, for example, has been much improved. Screws are so largely used in ironwork for connecting the parts together, that their manufacture, in the shape of what are technically called bolts and nuts, is a large trade of itself. The old method of forming the threads, namely the male thread by movable steel cutting ' dies,' fixed in a ' stock' or handle, and the female by cutting * taps,' is still the general one, but the arrangements have been much perfected, and the process has been much facilitated by screwing machines taking the place of hand labour. As machinery advanced, much inconvenience was found from the varying sizes of the threads, screws of the same diameter differing so much in this particular that it was scarcely possible to match a male and female screw unless they were actually made together. It occurred to Henry Maudslay that standard sizes ought to be adopted throughout the trade, and the idea was afterwards fully carried out by Whitworth, his pupil. In the present day, to form an ordinary screw-thread of any other size than ' "Whitworth's standard,' is little less than a crime in the eyes of educated mechanical engineers. For large exceptional screws, the lathe with slide rest is used, the automatic sliding motion allowing of such a progression being given to the tool as will form the required spiral in any given proportions, and with absolute perfection.

Sir Joseph Whitworth has also much promoted mechanical excellence in other respects; one for example in the mode of getting perfectly plane metallic surfaces; another in the establishment of a series of ' standard gauges,' for obtaining great accuracy and uniformity in the dimensions of moving parts in machinery.

The construction of automatic machine tools has been much stimulated and improved by the ' strikes ' and combinations of workmen that have taken place from time to time. These have caused so much inconvenience to the trade, that efforts have naturally been made to lessen the amount of manual skid requisite, and to reduce the human labour to a kind which may be performed by less practised hands. Hence every strike has been followed by improved tool machinery; already, not only has skilled labour been largely superseded, but the quality of the work has been immensely improved, and the price generally reduced also.

Mr. Whitworth gives an example of this in regard to the planing-machine. The original price for making a surface of iron true by the old process of chipping and filing was twelve shillings a square foot, whereas now it is done very much better by the planing-machine at a cost for labour of less than a penny.

The improvements in tools changed the mode of doing mechanical work, by rendering necessary large and carefully laid out manufactories. The old millwrights had little need of large or expensive premises or plant. A small workshop and a few simple tools were all they required; but under the improved conditions brought about by Watt's inventions, these no longer sufficed; it was necessary to have more systematic arrangements, and tools of complicated and often expensive character, and these necessities brought about the establishment of large manufactories, which gradually supplanted the old millwright's trade.

In these manufactories the designing and direction of the work passed away from the hands of the workman into those of the master and his office assistants. This led also to a division of labour; men of general knowledge were only exceptionally required as foremen or out-door superintendents: and the artificers became, in process of time, little more than attendants on the machines.

One important result of the improvements in the iron manufacture has been the use of this material for structures of much greater magnitude than formerly.

Iron bridges have been the most prominent objects of this kind. The example set at Colebrook Dale in 1770 was followed in other places by Telford and other engineers, and the cast-iron bridge culminated in the erection by Mr. Rennie, in 1819, of the magnificent Southwark Bridge over the Thames, which contains 0,000 tons of iron.

When malleable iron had come into use, of a quality that could be depended on, it was adopted in the first instance for bridges on the suspension principle, of which the elegant structure erected by Telford over the Menai Straits, in 1826, is the best-known example.

The introduction of railways soon after this date involved the necessity for bridges in large numbers, of a more substantial kind, and sometimes of large dimensions ; and malleable iron being a material very suitable for their construction, from the facility with which it could be fashioned and put together, a great demand for iron bridges set in. No very large structure, however, of this kind existed until the erection of the great Tubular Bridges over the river Conway and the Menai Strait, in regard to which, as will be seen hereafter, Mr. Fairbairn took an active and important part. The Menai Bridge is 1,511 feet long, and contains 11,468 tons of malleable iron.

Other examples of large structures in iron are found in modern iron ships. These have lately assumed great magnitude; the great war frigates of our modern navy often containing many thousands of tons of metal. The -celebrated 'Great Eastern,' designed by Mr. Brunei in 1858, weighs nearly 20,000 tons.

The iron armour-plates used on the war frigates are huge masses of malleable iron, the provisions for manufacturing which are of gigantic character; and the use of this material for defensive purposes has been carried further by the construction of massive iron forts of great strength and solidity.

The modern rifled wrought-iron guns, of many tons in weight, are not only very heavy forgings, but are fine specimens of accuracy in workmanship, that could only have been brought about by admirable perfection in the tools and mechanical arrangements employed in their manufacture.

From the foregoing description the reader will be able to form an idea of the nature and extent of the profession of which Sir William Fairbairn was one of the most distinguished members.

Having undergone a thoroughly practical apprenticeship with working millwrights and mechanics, he commenced business in 1817 by setting up a manufactory at Manchester; and from this date to his death, in 1874, he was in active and constant practice as a mechanical engineer.

During this long period he was engaged in the design and practical construction of engineering works in great variety, and on a large scale. Steam-engines, water-wheels, millwork and machinery of all kinds, steam navigation, the iron and steel manufacture, iron defences, iron bridges, and other large structures in iron, locomotives, and in fact almost every kind of subject embraced in the mechanical branch of the profession occupied his attention, and almost everything that he touched received some improvement at his hands.

But if he had done nothing more than what occupied him in his business capacity, he would not have acquired the name he has left behind him. He was not only an able designer and skilful manufacturer, but he devoted much time to original investigation and to the promulgation of mechanical knowledge. He was not, strictly speaking, an eminent theorist, for his education had been too plain and practical to allow of his acquiring high theoretical attainments; but he had a scientific mind, a great love of experimental enquiry, an indefatigable perseverance in tracing out mechanical truths, and a gift of expressing clearly the results he had obtained.

These qualifications prompted him to contribute largely to the spread of knowledge on professional subjects. He wrote many complete works, which became very popular; he sent many able but less known papers to scientific bodies; he was continually appealed to on intricate or difficult questions; and he was largely sought after to give public lectures or addresses on subjects bearing on mechanical science.

His ability and public spirit were acknowledged by the award to him of honours of the highest character, he was made a Fellow of the Royal Society, and received their gold medal; he was chosen President for one of the meetings of the British Association; he received honorary degrees from two British Universities; he had the great distinction of being elected one of the few foreign members of the Institute of France; and passing over many other marks of respect of a minor kind, he had, as a crowning honour, the dignity of a Baronetcy graciously conferred on him by Queen Victoria.

A long life, so spent and so rewarded, cannot fail to be of public interest, and the story of this life it is the object of the following pages to tell.

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