When Machines began to Replace Men Part 2

Ron continues his description of machines replacing Men

In the 1500s and 1600s there was the beginning of organised industry, wool cloth was England's biggest export, but much of it was produced in homes as a cottage industry. In the late seventeenth century relatively cheap cotton became available, mostly produced by slave labour in America and cotton based cloth became the mainstay. In 1765 Hargreaves invented his 'spinning jenny' that could handle several threads simultaneously, despite the opposition from those who produced textiles by hand, the concept of factories emerged using the power of water wheels. In 1769 Arkwright improved the technique with his 'water frame' and established his famous Masson and Cromford mills in the Derwent Valley near Matlock. These were large mills employing many people and utilising the water power of the river Derwent. The potential for expanding this industry was immense but the use of water power required the mills to be located in areas where there was fast flowing rivers, usually in hilly country, remote from the source of materials and remote from the markets for the goods produced. The only means of transport was by horse drawn carts over poor roads. An alternative source of power was urgently sought.

Glasgow University had their own working model Newcomen engine, in 1765 this engine broke down and a man by the name of James Watt was asked to repair it. It was Watt's first encounter with such a steam engine.

James Watt was born in 1736, the son of a boat builder, chandler and ship owner in Greenock. As a boy he worked in his father's workshop and was praised for his skill in making detailed models. Later he went to London and learned to be an instrument maker, he subsequently returned to Glasgow and became an instrument maker for Glasgow University where he gained the respect and friendship of the academics.

Although not familiar with the Newcomen engine he quickly understood its functioning and he was struck by the high fuel and steam consumption. He was right, had he been able to determine the efficiency of the Newcomen engine he would have discovered that it probably did not utilise more than one percent of the energy released by the combustion of the fuel. He was aware of the work on steam at the university and he knew that there was a large amount of heat required to change boiling water into steam, the latent heat. He thought about the poor efficiency for some time and finally concluded that the condensing of the steam cooled the cylinder to the extent that the initial incoming steam was also condensed and, in effect its latent heat was lost. It took a time for him to conclude that the solution would be to condense the steam in a separate condenser connected to the cylinder by way of a valve. This was a brilliant conclusion and he went on to obtain a patent for his separate condenser engine in 1768. Actually building the engine was difficult, he was short of funds and sought financial help from his friends. Watt himself was something of an obstacle, he was a perfectionist and hindered development by constantly thinking up ways of making the engine better and changing design details during construction. Eventually, after later teaming up with Boulton, a manufacturer with a 'manufactory' just outside Birmingham, Watt engines were being installed all over the country. Watt himself became quite prosperous but continued to work to improve his engine and to work as an inventor.

Although the Watt engine was more efficient it probably did not achieve better than 4% efficiency. Nevertheless this meant a quarter of the fuel consumption of a Newcomen engine and these Watt engines were in great demand. They were still beam engines mostly constructed by the purchaser with oversight by Watt's men. Initially his engines were required to meet the urgent need for removing water from mines, many of the Newcomen engines were found to be inadequate for the task. The mines were not the only location where the capability to pump water was a vital requirement. After Vermuyden had managed to drain much of the fens a new problem arose due to the shrinking of the peat soil as it dried. This resulted in the land and the drainage ditches sinking to a level below that of the rivers so that the water had to be lifted into the rivers. Initially this was achieved by wind driven pumps, these windmills had serious limitations, not least that they failed when the wind dropped. As the land continued to shrink the problem of raising the water to the level of the rivers became more acute. The arrival of the steam engine was the answer, at last there was the potential ability to pump as much water as was necessary. The first steam pumping station was at Sutton St. Edmunds, it employed a beam engine driving a scoop wheel and it began pumping in 1818. The largest of these early steam pumps could lift water through ten feet at the rate of 150 tons per minute.

As the 18th entury progressed there was a growing demand for engines with a rotary motion like that produced by water wheels. Another brilliant inventor by the name of Murdock, who was working on Watts' team, built an engine where the rocking motion of the beam was converted to a rotary motion using a simple epicyclic gear in 1784. Other rotary arrangements appeared and now the sky was the limit. Engines could be supplied for mills that could now be located where the people, the markets and better transport were available. In 1795 Murdock produced a rotary engine without the beam and using slide valves. Steam power could now be supplied for almost any task in a more compact form and capable of working harder and faster than could ever have been imagined. The industrial revolution was underway in no uncertain manner.

When the engines were used to pump water it was easy to express the performance in terms of the rate at which it was able to lift water. With the rotary engines it was necessary to have some measure of the rate at which the engine was able to work. At the time horses were still the primary source of work. Watt found it convenient to express the capabilities of his engines in terms of the equivalent number of horses working at the same time. One of Watt's customer's millwrights said that a mill horse walked a 24ft diameter circle and completed two and a half circuits a minute, that is about 60 yards a minute. It was thought that the horse pulled a force of 180lbs. From this Watt worked out the necessary dimensions for his engine. He also had a measure for his 'horse-power' 60x3x180 = 32400 ftlbs/min. Within a few years the workers at Boulton's factory were talking about the capability of their engines in terms of the number of horses. In 1809 the horsepower unit was formally defined as 33,000 ftlbs/min and that has remained the same in the Imperial system of units to this day.

Although Watt could see the potential for using steam at higher pressures and using it expansively he was concerned over the safety of boilers under pressure and opposed any developments along those lines. When his patent expired other developments using higher pressure steam followed rapidly, even producing engines with no condenser and the way was opened for the steam locomotive.

Ron Watts