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The Social and Industrial history of Scotland, from the Union to the present time
Eighteenth Century: 5. James Watt and the Steam Engine

Part of this prosperity was made possible by James Watt, the improver of the steam engine. Watt, who was born in 1736, early showed a capacity for mechanics. This capacity he inherited from his grandfather who had migrated from Aberdeenshire to Crawfordsdyke, near Greenock, where he taught mathematics and navigation, became bailie of the place, and latterly a prosperous merchant of Greenock. His father, who combined the occupations of shipwright, shipchandler, builder, and general merchant, was also a man of ability and took an active part, as member of the Town Council and Treasurer, in the affairs of the burgh. His mother, Agnes Muirhead, is described as "a gentlewoman of good understanding and superior endowments." Their son, James, was a delicate boy and received a good deal of his education from his parents. He was a precocious pupil with a taste for mathematics, and very dexterous in the use of the tools with which his father presented him. "Jamie has a fortune at his finger ends" was a saying among his father's workmen. He had the observant, enquiring mind that loves to make experiments and get at the secret of things, as the story of the tea kettle shows. Before he was 15 he had twice read Gravesande's Latin Manual on Physics and interested himself in electricity and chemistry. In 1754, at the age of 18, his father, having been overtaken by misfortune in business, sent him to Glasgow to learn the art of mathematical instrument maker. Whilst working for a time with a mechanic who repaired spectacles and fiddles and made fishing tackle, etc., he attracted the notice of Dr Dick, the Professor of Natural Philosophy, who advised him to proceed to London for further instruction in his chosen craft and gave him a letter of introduction to a friend. Through this friend he found in Mr Morgan, mathematical instrument maker, a master -willing to give him a year's instruction for 20. Fortified with this increased practical knowledge, he was back in Glasgow in 1758, bringing with him new tools and material wherewith to make others and hoping to start a business of his own. The Guild of Hammermen, in which a mathematical instrument maker was required to enrol, required, however, an apprenticeship of seven years in the burgh and without this qualification he could not be admitted. Happily his friends in the University, Adam Smith and Joseph Black among them, came to the rescue and not only employed him as instrument maker within its precincts, where the laws of the Guild did not prevail, but allowed him a room where he could exhibit his instruments for sale. There was, however, little demand for his quadrants and other products and he was fain to make or mend a variety of articles such as fiddles and flutes, spectacles and fishing tackle in order to subsist. Black gave him an order for an organ and though he knew nothing about organs and had no ear for music, he had an extraordinary, aptitude for learning how to make things, and made up for the defect by studying the laws of harmony. The organ was, therefore, forthcoming in due course and was a remarkable success.

In the winter of 1763-64 he turned his attention to the application of steam as a motive force. He began by experimenting with Newcomen's engine, a model of which was in the University. The steam generated in the boiler only produced a few strokes in the piston which works the engine, and the engine stopped. More steam was generated, and the engine would not work at all. The piston in the cylinder in Newcomen's engine was forced up by the steam and thrust down by the pressure of the air on the open top of the cylinder. But the condensing of the steam cooled the cylinder and thus interfered with the steady working of the piston. How to remedy this defect, produced by condensation within the cylinder, was the problem. In seeking a solution Watt began by investigating the properties or nature of steam. He realised that invention depends on the grip of scientific principles—the study of the facts or phenomena of nature, apart from any practical application of them, as the true way of arriving at this application. Moreover, he possessed in an eminent degree the faculty of mastering every phase of a subject which excited his interest and engaged his attention— the true test of success in any department of work. As the result of his investigation, he discovered the fact of latent heat in water transformed into steam, which, unknown to him, had already been discovered by Dr Black. He found that one pound of steam blown into cold water heats it six times more than one pound of boiling water poured into the cold water does. This higher rate is the amount of latent heat in the steam. He further found that the total amount of heat in the steam remains the same whatever the pressure, but that 4/5ths of it was lost in heating the cold cylinder and that only l/5th acted on the piston. The problem now was to get the total heat of the steam to act on the piston so as to increase its power fourfold. For this purpose the cylinder in which the piston works had to be as hot as the steam, and to secure this the steam had to be carried off into a separate condenser instead of being left to condense within the cylinder and thereby cool it. This was the truth that flashed on his mind as he walked one Sunday afternoon, early in 1765, on Glasgow Green. To maintain the cylinder at the required temperature he encased it, leaving a space, between it and the case, filled with steam. The cylinder he used for this purpose was a brass syringe connected with a tin can, which served as a condenser, into which the steam rushed after driving up the piston, which was thrust down by the air pressure into the vacuum thus created, and driven up again by a new blast of steam into the cylinder, and so on as long as the steam was applied. The experiment made with this primitive contrivance was a triumphant demonstration of the idea that had flashed on his mind on that fateful Sunday afternoon.

This experiment he toiled to bring to practical fruition in the model engine which he constructed in an old cellar in the city. The difficulties in the way of success were increased by the lack of skilled workmen in the making of the parts and their consequent imperfections. The result was that it "snifted at many openings," or joints, and would not work smoothly. A second and larger one, begun in a more commodious workshop, was a great improvement on the first, though it also, on being set to work, revealed many defects of workmanship. These defects were, however, only mechanical; the principle of the separate condenser was absolutely correct. Want of funds was another difficulty, for the invention could not be perfected without money and the patent which he desired to take out was an expensive matter. The Government of the day certainly did not show an enlightened interest in scientific invention, or any adequate sense of its practical value. He had, besides, to work for his living and do surveying in connection with the canal schemes of the period, and this made heavy inroads on the valuable time which should have been given to the work of perfecting the engine. Dr Roebuck helped and Dr Black also. At last in 1768 he succeeded in constructing a model which worked smoothly. In August of that year he went to London to secure the patent and after distracting delays finally, on January 5, 1769, obtained it.

Success was, however, still mitigated by failures. An engine, constructed on the successful model, to work Dr Roebuck's coal pits at Bo'ness, showed many defects owing to the imperfect workmanship of the mechanics—so great is the distance between a successful model and a successful working engine. Worse still, Dr Roebuck got into financial difficulties over his pits and Dr Black had to come to the rescue to pay for the patent. Happily a new friend and co-operator came on the scene in Matthew Boulton of Birmingham. In 1775 began the memorable partnership in the manufacture of engines, though lack of trained mechanics was still a serious drawback. Orders came from mine-owners for engines to pump their mines. But there were financial anxieties not a few to overcloud the expansion of the new enterprise, to which Boulton contributed his rare business ability and Watt his still rarer inventive genius. The development of the engine by a series of further experiments increased the demand for it by enabling it to be used for a great variety of practical work. This development consisted in adapting it to produce a rotatory motion and thus turn the wheels of all kinds of mills and machines, in the use of steam on the expansive principle, in the double acting engine by which steam, instead

of the air, as in Newcome's engine, was used to the piston downwards as well as upwards, in the composite engine in which the same steam worked the piston of a second cylinder and thus doubled the power. These and other improvements were covered by the patents of 1781, 1782, and 1784, and at last, in the second half of the twenty-five years of co-operation of the two partners, prosperity dawned. Both retired in 1800, leaving the management of the firm to their sons, and Watt was enabled to enjoy the fruits of his strenuous career in a happy old age " when he enjoyed life as he had never done in his youth." He lived nearly twenty years after his retirement, dying at Heath-field in Staffordshire in 1819, after he had seen the application of the steam engine in the steamship and the railway locomotive.

In 1787 Mr James Taylor suggested to Mr Millar of Dalswinton, to whose sons he was tutor, the idea of applying the steam engine to propel ships. Mr Millar caught at the idea as a solution of the problem of propelling ships by mechanical contrivance, to which he had for some time been directing his attention. To this end he had made use of a paddle wheel fitted between two boats and turned by the hand. By this device he had succeeded in propelling a double boat at a speed of several miles an hour on a trial trip made from Leith. Taylor suggested to him that steam should be applied as a substitute for manual power in order to obviate the severe labour required to move the. paddles. He found in William Symington an engineer capable of carrying out his idea. Symington constructed an engine to be used for driving the paddles and the experiment took place in Dalswinton Loch in the summer of 1788. The engine mounted by him on the deck of the double boat propelled the paddle wheels, placed in the space between the two boats, at the rate of five miles an hour. The experiment was a success, but nothing further was done to develop it until 1801, when Symington succeeded in interesting Lord Dundas, one of the directors of the Forth and Clyde Canal, in the enterprise. Taking advantage of Watt's improvements, he constructed an engine which propelled a paddle boat, the Charlotte Dundas, on the Canal at a speed of between six and seven miles an hour. The boat was used to tow barges on the Canal and was the fir^t steam propelled vessel to be put to practical use. Unfortunately the directors of the Canal, fearing lest the action of the waves caused by the paddles should damage the canal banks, decided to discontinue its use, and Symington, the inventor of the first practical steam boat, having failed to obtain an annual pension from the Government, died in poverty.

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