Greetings from iainthepict. This blog of mine is meant to be like a 'Book of Days' or a kind of 'Scottish Year Book' if you will. The idea was to present an event for each day of the year. Somewhere in here, you can find out what happened, affecting Scotland and the Scots, on any given day of the year. Your comments and observations are very welcome.
The photograph is by Sam Perkins (check him out on Facebook at Sam Perkins Photography) and was taken near Oban.

Thursday, 25 August 2011

James Watt

James Watt, instrument maker, mechanical engineer and inventor, died on the 25th of August, 1819.

Contrary to what many people probably believe, James Watt did not invent the steam engine. In fact, steam engines were already in existence and being used to pump water out of mines nearly forty years before Watt was born. Thomas Savery patented a steam engine in 1698, which was improved in 1712 by another Thomas, a Mr. Newcomen, who died before Watt was born and who used in his advanced design the piston, which had been invented twenty-two years earlier, in 1690, by the Frenchman, Denis Papin. The man responsible for most of the myth surrounding James Watt having invented steam engines was another Frenchman, Fran├žois Jean Dominique Arago, an eminent mathematician and physicist. In 1839, twenty years after Watt’s death, Arago penned a eulogy and it was therein that the story of the young James sitting by the kitchen range watching a steaming kettle first appeared.

However, taking James Watt’s fundamental contribution to steam engine technology into account, it’s not surprising that he is often mistaken as the creator of the steam engine. It’s stretching things too far to suggest that nearly every successful and important invention that marked the emergence of steam power originated in the fertile brain of James Watt. About that, we can be sure the supporters of fellow Scot and Boulton & Watt employee, William Murdoch, would have something to say. What is certain, however, is that the Industrial Revolution got an almighty kick start from the work of James Watt. His revolutionary improvements to Newcomen’s steam engine led to what we could rightly call the Steam Age.

Watt’s creative genius converted a machine used to pump water out of Cornish mines into the driving force behind the rise of cotton and woollen mills in the heart of industrial England. Watt helped to radically transform the world from ‘rural agricultural’ into ‘urban industrial’ as his engines were used to pump bellows for blast furnaces, power huge hammers for shaping forged metals, and turn machinery in the mills. By 1800, when the Boulton & Watt patent rights finally expired, after extensions granted in 1778 and 1785, there were more than five hundred of Watt’s machines in Britain’s mines and factories and they had earned him a small fortune in royalties. Watt invented the term ‘horsepower’ when he calculated a horse’s pulling power in comparison to that of his engine. He used his calculation to determine the sum able to be saved by using his engine instead of horses. From that reckoning, Watt determined an annual payment, equal to a third of the potential saving, which Boulton & Watt was to receive for the duration of validity of Watt’s patent. As an example of such sums, they got £800 per year for three engines operated by one firm in Chacewater, in Cornwall.

Watt’s initial efforts at increasing the effiency of the steam engine stemmed from another calculation. He figured that eighty per cent of the energy was wasted on heating up the cylinder every cycle. Watt solved that problem by inventing a tubed condenser and an air pump or ‘stuffing box’ to prevent steam from escaping, thus maintaining a vacuum in the chamber. He also created ‘steam-jacketing’ insulation in order to maintain the high temperatures needed for maximum efficiency. Murdoch didn’t have a hand in that.

Other improvements that Watt made upon Newcomen’s engine, without any input from Murdoch, included oil lubrication and the ‘steam indicator’ or pressure gauge. A further major innovation of Watt’s was the ‘double-action’ piston engine, in which steam is admitted alternately into each end of the cylinder so that the piston is driven in both directions, rather than relying on atmospheric pressure to complete the ‘condensation-vacuum’ stroke-cycle. The invention of which Watt was most proud was the rigid, three bar ‘parallel motion’ linkage, created to match the rocking motion of the beam (which traces an arc) with the linear motion of the piston. That enabled the piston to push the beam on both upward and downward strokes. Another major contribution to instrumentation and machine control that was developed by Watt deserves a mention; the centrifugal governor, which came to be known as the ‘Watt governor’. It included a steam throttling valve and a mechanism, which regulated steam flow to the piston and maintained a constant engine speed.

Watt is also credited with inventing the ‘sun and planet’ gear system, but so too is William Murdoch. It may well be that the two Scotsmen collaborated, despite Watt’s name being on the 1781 patent. That Watt registered the patent shouldn’t be too surprising, considering that Murdoch was his employee; things would be the same today and Murdoch never contested the patent. The new fangled gear ingeniously changed the reciprocating, up-and-down motion of the piston beam end, which was good for pumping water and draining mines, to a rotary movement that could be used to drive machinery for grinding, weaving and milling. In addition, it permitted the wheel to turn more than once per piston stroke, resulting in a major improvement in productivity. The rotary engine was undoubtedly key to another form of revolution; the Industrial Revolution.

James Watt was born in Greenock on the 19th of January, 1736. Wee Jamesie was a peely wally creatur and as a consequence, he got most of his elementary schooling at home from his Ma and Pa. James attended school irregularly, but by his early teens had demonstrated an aptitude for instrumentation and tooling, gained through the encouragement of his shipwright father. In 1754, as a result of showing such promise, James was sent to Glasgow to become an instrument maker, where he so impressed a university professor, Robert Dick, that he was promptly advised him to move to London. Nothing loath, James rode south in 1755 and managed to find work. Notwithstanding the rules of the Worshipful Company of Clockmakers, which required a seven-year apprenticeship, James was taken on by a John Morgan, but ended up working ten-hour days in an attempt to condense the seven years into as short a time as possible.

Unsurprisingly, James’ poor health didn’t improve in ‘the Smoke’ and after a year, he was back in Glasgow. However, because he hadn’t completed a formal apprenticeship, James fell foul of the Glasgow Guild of Hammermen, which obstructed his plans to open up shop, despite his newly acquired trade being little practised in Scotland. Thankfully, as a result of earlier friendships, Glasgow University offered him the use of premises within its precincts, where, from 1757 until 1763 when he was allowed to open a workshop in the Saltmarket, Watt repaired scientific apparatus and made musical instruments. Those instruments comprised Watt’s earliest inventions, in which he contrived improvements to the construction of organs.

By 1768, Watt had begun a secondary career as an engineer and surveyor. Watt was employed to survey the Forth & Clyde Canal and, in 1773, the Caledonian Canal, built by Thomas Telford. Watt was responsible for the superintendence of the Monkland canal and he surveyed the Perth & Forfar canal and the Crinan canal, which was built by John Rennie. Not content with instrument making, surveying and subsequently becoming famous as the ‘father of steam’, Watt turned his hand to other things during his long life. He invented micrometers for measuring distances at sea and, in 1780, Watt gained a patent for a copy machine. And, not content with inventing the first photocopy machine, Watt also turned out a portable version.

James Watt breathed his last on the 25th of August, 1819, at his home in Handsworth, in Birmingham. He was buried on the 2nd of September in the grounds of St. Mary’s Church, in Handsworth. History’s view of James Watt is substantially more complimentary than this quote from a letter to Joseph Black, in which he wrote, “Of all things in life, there is nothing more foolish than inventing; and probably the majority of inventors have been led to the same opinion by their own experiences.”

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