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James Watt, the grandson of a teacher
of mathematics, and the son of a shipwright merchant of Greenock, was born
in 1736. On the advice of a Glasgow Professor, he was sent to London in
1755 to be apprenticed to a mathematical instrument maker. However, on
arriving in London he discovered that the seven years' apprenticeship rule
of the gild was largely insisted upon, and it was only with difficulty
that he could find any one who would take him for so short a time as a
year This was finally arranged, and a Mr. Morgan was to give him a year's
instruction for twenty guineas.
His stay in London was characterized
by great frugality and occasional fears of the press-gang In a letter to
his father, he writes: " They now press anybody they can get, landsmen
as well as seamen, except it be in the liberties of the city, where they
are obliged to carry them before my Lord Mayor first; and, unless one be
either a Prentice or a creditable tradesman, there is scarce any getting
off again, and if I was carried before my Lord Mayor, I durst not avow
that I wrought in the City, it being against their laws for any unfreeman
to work, even as a journeyman, within the liberties."
When James Watt had completed his
training, he returned to Glasgow to set up in business for himself, only
to be met by the same restrictions that existed in London; the gilds were
still struggling to retain their control of the trade of the chartered
towns, and as Watt was neither the son of a burgess nor the husband of
the daughter of one, and not having served a regular apprenticeship, he
was refused permission to open his shop. Watt's early friendship with the
Glasgow professors now stood him in good stead. He was made mathematical
instrument maker to the University, and given a shop within its walls,
where he carried on his trade. Even in this small venture Watt lacked capital,
and took one John Craig into partnership, the details of which give an
insight into the scale of a small business in 1750, and the relatively
small part fixed capital played. The journal of the partnership begins
with the following entry: " An Inventory of tools, goods, etc., belonging
to us, James Watt and John Craig, each one-half. Taken October 7th, 1759,
at Glasgow," and then enumerates a variety of mechanical tools from a turning
lathe to a flatting mill, with philosophical instruments, chiefly mathematical
and optical, the whole to the value of which £91 I9S. 3.5d., with
cash on hand, £I08 8.5d., made the total capital £200.
During the period dealt with in the
journal, 1759-1765, the ready money sales brought in about £50 per
month, or £600 per annum, a large portion of which went to pay wages
and buy materials. Watt, himself, is credited with a salary of £35
per annum, rather more than twice the wage of a potter, and rather less
than twice that of a miner. From employing one journeyman and occasional
extra help, the business expanded so that in 1764 Watt employed sixteen
men of various capacities.
In 1763, James Watt left his rooms
in the University, and in July of the following year married his cousin,
Miss Miller. During this time, too, Watt made the acquaintance of Professors
Black and Robison, of Glasgow University.
During his stay in the University,
Watt looked after the mathematical instruments which belonged to it, and,
" in the winter of 1763-4, having occasion to repair a model of Newcomen's
engine, belonging to the Natural Philosophy class," his mind was again
directed to the study of the steam engine.
He repaired it, but upon its being
set to work, it was discovered that it would only go a few strokes at a
time, though the boiler was big enough to keep it well supplied with steam.
The large amount of water that it was necessary to inject to condense the
steam, put Watt on the track of the theory of latent heat, which Dr. Black
had already discovered.
Upon
thinking the matter over, James Watt saw that there was a great wastage
of steam and power through the alternate heating and cooling of the cylinder,
and, upon reflecting further, he perceived " that in order to make the
best use of steam, it was necessary first, that the cylinder should be
maintained always as hot as the steam which entered it; and, secondly,
that when the steam was condensed, the water of which it was composed,
and the injection itself, should be cooled down to a 100 degrees, or lower
where it was possible. The means of accomplishing these points did not
immediately present themselves; but early in 1765 it occurred to me that
if a communication were opened between a cylinder containing steam and
another vessel, which was exhausted of air and other fluids, the steam,
as an elastic fluid, would immediately rush into the empty vessel, and
continue to do so until it had established an equilibrium; and if that
vessel were kept very cool by an injection, or otherwise, more steam would
continue to enter until the whole was condensed. But both the vessels being
exhausted, or nearly so, how were the injection water, the air which would
enter with it, and the condensed steam, to be got out?" This was eventually
solved " by employing a pump or pumps to extract both the air and the water,
which would be applicable in all places, and essential in those cases where
there was no well or pit."
This is James Watt's great discovery
the theory of separate condensation, it made the steam engine a useful
and economical source of power, and was so successful, that for a hundred
years after his invention no drastic alterations were made in the type
of steam engines in common use. Following naturally from the main discovery
were these corollaries. The piston in Newcomen's engine was kept air-tight
by a supply of cold water on it upper surface- this was no longer possible,
and Watt was forced to use " oils, wax, resinous bodies, fat of animals,
quicksilver, and other metals in their fluid state."
Again, the cylinder being open, the
air which entered to press down the piston in the old atmospheric engine
would cool the cylinder. Therefore, he proposed to close the head of the
cylinder, and to allow the piston rod to slide through a stuffing box,
while the piston was to be forced down, not by the air, but by steam introduced
above it.
The cylinder was cooled, too, by
the open air on its side; this Watt remedied by enclosing the cylinder
in a second case covered with wood, and filling the space between with
steam. Thus, all Watt's improvements were economical of heat. Economy in
heat meant economy in steam, and economy in steam meant economy in working
costs, and, above all, in coal.
James Watt now spent all his spare
time in reducing the theory of his improvement to practice; he carefully
thought out all the details, and calculated the amount of steam required.
But, before long, he felt the need of an experiment on a large scale.
That is the story of the inventor,
but the invention was a long way from being a commercial proposition, and
much money had to be spent, and much capital laid out before Watt was in
a position to supply power to order.
James Watt himself had no money to
spend on experiments, and no capital with which to start manufacturing
steam engines, should his experiments prove successful. Therefore, he had
to look elsewhere for his capital, and the two men who provided it, and
made possible the successful development, were Roebuck and Boulton. Their
story forms an important chapter in the history of capitalism, and in their
careers can be seen most of the difficulties and opportunities that faced
the men who became the leaders of the Industrial
Revolution.
Next
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Boulton
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