2.            James Watt ( 1736-1819) was born into a lower middle class family and was trained as an instrument maker. According to the Fontana history of Technology, “ as a child he showed unusual mathematical ability, a keen interest in Newtonian natural philosophy and great mechanical skill….the University of Glasgow employed him as an instrument maker. In 1757 the university allowed him to set up shop within its precincts, advertising himself as ‘ Instrument Maker to the University’….The small ‘Glasgow College’, with barely a dozen professors and virtually no supporting staff, was extraordinarily rich in talent: Adam Smith and Joseph Black were among the professors……Called on to repair a model Newcomen  engine belonging to the University, Watt noticed that the cylinder became very hot when full of steam but was considerably cooled in the condensing phase….Watt inferred that too much steam was being used  merely to heat up the cylinder only to be wasted in the condensing phase…It might even be that the alternate heating and cooling of the cylinder was a diseconomy in the working of large engines……What was required was a substance that would absorb much less heat as the steam warmed it up. Black had found that wood had a much lower heat capacity than any metal….Watt  therefore made a cylinder of wood , treated it with linseed oil and baked it. Experiments showed that much less steam was required to fill it….  However, on adjusting the condensing jet to ensure that no more cold water was injected than was necessary to condense the volume of steam, he found that the power of the engine was seriously reduced. The temperature of the condensate …was so hot that it would boil in a vacuum, and go on boiling until the vacuum was vitiated…….The solution occurred in a flash of understanding and insight while Watt was walking near the ‘Golf House’ on Glasgow Green on Easter Day 1765.If TWO cylinders are used, one, in which piston moves, can be kept hot all the time while the other, in which the steam is condensed, can be kept cool all the time….The broad details of the complete engine rapidly streched  themselves out in Watt’s mind…..Watt patented his engine in 1769.”

3.            His first engine was not a success. Later he developed a better one jointly with Matthew  Boulton (1775).They made their names and a great deal of money in Cornwall  and by 1796 started manufacturing complete engines themselves.

4.            Continuing the story of the steam engine the Fontana history goes on as follows. “ the  launch of the Watt engine was unquestionably a major entrepreneurial achievement………example of an outsider bringing in revolutionary ideas to an established technology…his use of the new scientific ideas  pioneered by Black……related to the latest, progressive, science….  There were, during the period of Watt’s monopoly, many attempts to pirate or to evade his patent. One way…through the so-called ‘pickle-pot ‘ condenser …which are more economical…Watt, it seems, never contemplated compromises with his ideal engine beyond those enforced by the market…..Watt standardized the unit of horse  power. In 1783, when he began to sell rotative machines, he described his engines    in units of ‘horse power’ … one horsepower representing 33000 pounds raised one foot in one minute….He remained throughout his long life strongly opposed to the use of high pressure steam even though it would allow smaller, more powerful engines…and would enormously widen the market for the steam engine…..it was the high pressure steam engine that, from the time Watt’s extended patent finally expired in 1799, was to dominate and utterly transform life in the century to follow. If Watt failed to  foresee the future  it is also surprising that Adam Smith , in his Wealth of Nations (1776) , made no reference at all to steam engines, much less to the radically improved version that his young colleague had invented”. 

5.            The crucial role of the  Watt’s engine  has been exquisitely elaborated by Karl Marx in his monumental work , Das Kapital ( Cf. Karl Marx, Capital,vol 1, Progress publishers, Moscow) . According to him it was not the steam engine which created the IR , instead the one which made the IR possible. His description of this great phenomenon is as given below.

6.            In modern industry “ the revolution in the mode of production begins with the instruments of labour”, said Karl Marx  while differentiating the ‘machinofacture’ from ‘manufacture’…. “ The machinery consists of three parts, the motor mechanism, the transmitting mechanism and finally the tool or working machine. The motor mechanism puts the whole into motion. It either generates its own motive power, like the steam engine or the electromagnetic machine , or it receives its impulse from some already existing natural force , like the water wheel from a head of water, the wind mill from the wind, etc. The transmitting mechanism, composed of flywheels, shafting, toothed wheels, pulleys, straps, ropes, bands, pinions, gears of varying kinds , etc. regulates the motion, changes the form  wherever necessary as for instance from linear to circular motion, and divides and distributes it  among the working machines. These two parts are thus essentially only for putting the machines into motion. The tool or working machine is  that part of the machinery  with which industrial revolution of the 18th century started and continued ever since….The machine proper is therefore a mechanism that, after being set in motion, performs with its tools the same operations that were formerly done by the workman with similar tools. Whether the motive power is derived from man or from some other machine, makes no difference  in this respect. From the moment that the tool proper is taken from man, and fitted into a mechanism , a machine takes the place of a mere implement. The difference strikes one at once, even in those cases where man himself continues to be the prime mover. The number of implements that he himself can use simultaneously, is limited by the number of his own  natural instruments of production, by the number of his bodily organs. In Germany, they tried at first to make a spinner work two spinning wheels. This was too difficult. Later a  treddle spinning wheel with two spindles was invented. The Jenny on the other hand even at its birth spun 12-18 spindles, and the stocking-loom knits with many thousand needles at once and so on…

7.            “Increase in the size of the machine , in the number of its working tools, calls for a massive mechanism to drive it; and this mechanism requires, in order to overcome its resistance, a mightier moving power than that of man, apart from the fact that man is a very imperfect instrument for producing uniform continued motion. But assuming that he is simply acting as a motor, it is evident that he can be replaced by natural  forces. Of all the great motors handed down from the manufacturing period, horse power is the worst, partly because a horse has a head of his own, he is costly and his applicability in factories is very restricted ! Nevertheless the horse was extensively used during the infancy of the modern industry, with the term ‘horse power’ surviving even now as an expression of mechanical force !

8.            “Wind was too inconstant and uncontrollable and use of water power preponderated in England even during the manufacturing period. In the 17th century attempts were made to turn two pairs of millstones with a single water wheel. But the increased size of the gearing was too much for the water power. And this was one of the circumstances that led to a more accurate investigation of the laws of friction. In the same way the irregularity caused by the motive power in mills that were put in motion by pushing and pulling a lever , led to the theory and application of fly-wheel. In this way, during the manufacturing period, were developed the first scientific and technical elements of modern mechanical industry. The use of water, as the predominant motive power, was again beset with difficulties. It could not be increased at will, it failed in certain seasons, and , above all, it was essentially local..

9.            “Not till the invention of James Watt’s second and so-called double-acting steam engine , was a prime mover found that begot its own force by the consumption of coal and water, whose power was entirely under man’s control, that was mobile and as a means of locomotion, that was urban and not, like water-wheel, rural, that permitted production to be concentrated in towns instead of, like the water-wheel,  being scattered up and down the country, that was of universal technical application, and, relatively speaking, little affected in its choice of residence by local circumstances. 

10.            “The greatness of Watt’s genius showed itself in the specification of  the patent he took out in April 1784 . In that specification his steam engine is described , not as an invention for a specific purpose, but as an agent universally applicable in Mechanical Industry. In it he points out applications, many of which, as for instance the steam-hammer, was not introduced till half a century later. ….Nevertheless he doubted the use of steam engines in navigation. His successors Boulton and Watt sent to the exhibition of 1851 steam engines of colossal size for ocean steamers.”

11.            The oldest  surviving   rotative engine , built by Boulton and Watt in 1785, for the London Brewery of Samuel Whithead to drive the malt crushing mill, with modifications served the brewery for 102 years till 1887. This is now resting in working condition at the Power House  Museum at Sydney. With a speed of 20 revolutions per minute and a mean effective pressure of 10 pounds per square inch, the 25-inch piston of 6-feet stroke would have produced about 35 horse power in its prime.