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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. |
