Sunday, 31 May 2015

Iron and Steel, Part 1: Early Times

Iron is a common element in the earth's crust, but it is hardly ever found in its raw state; and difficulties involved in smelting it meant that its use came relatively late. By comparison, there is evidence of copper-working from about 4000 BC. It was perhaps discovered accidentally: Neolithic people made pottery, and maybe found beads of copper formed from stones used to build a kiln. Pure copper is too soft to be very useful, but it was found to become much harder if alloyed with tin (to form bronze), zinc or other elements. Many ancient civilizations were based on bronze-making: Egypt, old Babylonia, Minoan Crete and Mycenaean Greece, where Homer’s heroes fought with bronze weapons. The Greek poet Hesiod (8th century BC) knew that a Bronze Age preceded the Iron Age of his own day. There were also Bronze Age empires in China, suggesting that metal-working might have been discovered independently in different parts of the world.

  Iron working began about 1200 BC in what is now Turkey (and perhaps independently in China, where it developed rather differently). Manufactured iron takes one of three forms:-   
Wrought iron contains only about 0.04% carbon and minute traces of other elements. It is worked by hammering or rolling, and pieces can be heated in a forge and welded together. It rusts only slowly, but in its pure form is rather soft. It is not much used nowadays: things like decorative “wrought iron” gates are really mild steel.  
Cast Iron is about 4% carbon. It is cast in a mould, but cannot be forged. It is much harder than wrought iron and is strong in compression (bearing heavy loads from above) but weak in tension (if bent, it tends to break suddenly). It does not rust, and therefore today is found in things like drain covers.
Steel.   Mild steel is about 0.25% carbon. Steel is much harder than wrought iron, and can be cast or forged and welded. It is prone to rust. Its qualities are improved by alloying it with other metals; e.g. nickel, chromium or tungsten. Many modern steels are less than 50% iron.

This model from the Science Museum illustrates early iron working

A small furnace was constructed of stones and clay, containing iron ore (iron oxide, or more complex compounds) and charcoal, and bellows were then worked for several hours. When the temperature rose above 800 degrees, the charcoal burned to produce carbon monoxide, which reacted with the oxygen in the iron ore to leave iron and carbon dioxide. Because iron ore usually contains various silicates, crushed limestone (calcium carbonate) was also needed as a catalyst; reacting with these to produce calcium silicate; a shiny mineral commonly known as slag. Eventually the ironmaster would judge it was time to halt the process and open the furnace. If successful, he would find inside a lump of iron, perhaps not much larger than a cricket ball, also containing bits of slag, limestone and charcoal. This would then be delivered to a forge, where a smith would hammer it to drive out the rubbish, ending up with a piece of almost pure wrought iron. This would usually be shaped into bars for convenience, which other smiths would forge into tools, weapons and other useful objects.
     For well over 2,000 years, this was the only way of making iron! The Romans, for instance, never discovered any better system. Therefore, any metals were expensive, and most tools were still made out of wood whenever possible.

    The coming of iron weapons was apparently linked with enormous changes. Around this time (1000 BC) the ancient empires collapsed in the face of massive tribal movements. Mycenaean Greece disappeared, and the Egyptian New Kingdom overthrown by the invasion of the “sea peoples”, who were possibly our old friends the Philistines. In the Bible we are told that the Philistines controlled the supply of iron, and tried to stop any getting to Israel. The first iron age empire was the Assyrians.

Wrought iron had only limited uses for weapons or tools: being soft, it tended to blunt or notch easily. But very early on, smiths discovered a way to improve it. If they heated up iron to above red-heat and then cooled it rapidly (e.g. by plunging it in water) it became much harder. This was called tempering, or quenching. What happened was that tiny quantities of carbon were absorbed in the surface of the iron, creating a layer of steel a few molecules thick. This is now called “case-hardening”. If the iron was then repeatedly heated, hammered out and quenched, a kind of multi-layer sandwich of steel was created, suitable for making a sword. This was a highly skilled process, entirely dependent on the judgement of the smith, who worked with rituals verging on the magical, because no-one knew the chemical processes involved (“temper once in running water, once in dew, once in blood”, for instance). In "Moby Dick", when Captain Ahab forges a weapon to kill the white whale he asks his three harpooners to give their own blood for the final tempering.   
    I believe this is how we have legends of "magic swords", which were given names and were handed down from generation to generation. Probably most steel in the days of primitive technology was poor quality, but occasionally a smith might produce a blade of top-quality steel, probably as a result of some fortuitous alloy, which would cut through other weapons and armour of the time. By about the 12th century, as techniques improve, we no longer come across magic swords.  
      A slender piece of well-tempered steel, if bent, will spring back to its original shape. Top quality fencing foils can bend almost in a semicircle and spring back; though they will weaken with each bending and will eventually break.

Iron manufacturing was changed for ever with the invention of the blast furnace about 1450 AD, probably initially in Belgium, whence it quickly spread throughout western Europe.
What’s different here? The ingredients are exactly the same (iron ore, charcoal and limestone) but the furnace is much bigger, about 30 feet high, and is a permanent structure. The ingredients are filled from the top, usually by wheelbarrow. The main difference is the much higher temperature, achieved by a far stronger blast of air – hence, blast furnace. Above 1535 degrees, the iron melts to a liquid, and being heavier than anything else, accumulates at the bottom of the furnace, where it is held in place by a clay plug, with the slag and any other rubbish floating on top. This is Cast Iron, with a high carbon content (plus usually a few accidental traces of other elements). When the ironmaster decides the time is right, the clay plug is broken, and the molten iron runs out into a trough of sand, thence into side-troughs. These were thought to resemble lines of pigs feeding at a trough: thus "pig iron"
    A blast furnace could be working continuously: fed from the top and the iron tapped off at intervals, usually twice a day; producing in the early days about a ton of pig iron every 24 hours. It would only be stopped (“blown out”) if repairs were needed, or for some other reason. The record for a modern furnace is 38 years continuous blasting! 
     Thus vastly greater quantities of iron were produced than ever before, but there were defects. The first was that such a powerful blast of air could not be achieved by human strength, or even by horses. Only a waterwheel in a strongly flowing river could achieve it. (Perhaps this is why the Romans never invented blast furnaces: not only did they despise practical science, but they relied upon the muscle-power of slaves and barely developed watermills). One consequence was that blast furnaces often had to be “blown out” in summer if water levels dropped too low to power the bellows. The iron industry in the Black Country region near Birmingham was held back by the lack of suitable water-power.
    Secondly, huge quantities of charcoal were needed. To smelt a ton of pig iron required the felling of an acre of hardwood! By Elizabethan times, there were serious concerns about England becoming deforested! The early iron industry was found in places like the Weald of Sussex, with plentiful timber and “hammer-ponds” to provide the power. The obvious answer would be to use coal in the furnaces, but it was found that the iron produced was useless because it was weakened by elements absorbed from the coal: principally sulphur, but also phosphorus. In the 17th century, Dud Dudley in the Black Country claimed to have successfully smelted iron using coal, but if true, his secret died with him.
     Thirdly, cast iron had limited uses. It could be melted and then cast into pots and pans and fire-grates, but industry wanted more wrought iron, and conversion was a difficult process.

Pig iron would be transferred to a furnace called a Finery, where it would be melted and stirred and air blasted across to burn off the carbon. It was then placed under water-powered trip-hammer which shaped it into a block called a Bloom, driving out any impurities.  Next it went to another furnace called a Chafery, where it was hammered again into a bar. Lastly came a Slitting Mill, where it was rolled out and cut into narrow bars. The whole procedure was known collectively as a Forge.
     All these operations required water-power for bellows and more supplies of charcoal. Because a single water-wheel might not be powerful enough to power all these operations, the different furnaces might be some distance apart, increasing the expense.
   The first region of Britain to develop a modern iron industry was Coalbrookdale in Shropshire. This will be covered in my next essay.
A trip-hammer in the Coalbrookdale museum. The springs are modern!

Sunday, 24 May 2015

Quiz: Sports Stadiums

In which towns or cities are the following sports venues?

1. Allianz arena
2. Bernabeu
3. The "Bird's Nest"
4. The "Cake Tin"
5. Candlestick Park
6. Croke Park
7. Dodger Stadium
8. The "Gabba"
9. Goodison
10. Headingley
11. Ibrox
12. Lambeau Field
13. Lord's
14. Madison Square Garden
15. Murrayfield
16. Nou Camp
17. Newlands
18. Old Trafford
19. Parc des Princes
20. San Siro
21. Soldier Field
22. Trent Bridge

Answers will follow!

Thursday, 14 May 2015

The Duke of Wellington's Duel

In 1829, while he was Prime Minister, the Duke of Wellington fought a duel with a fellow-nobleman, Lord Winchilsea. This event, which sound so extraordinary to us, was not unprecedented for men of Wellington's generation. Duelling had been illegal for many years, yet two cabinet ministers, George Canning and Lord Castlereagh, had fought a celebrated duel in 1809, in which both sustained minor wounds. In May 1798 the then Prime Minister, William Pitt (who, it is easy to forget, was born only ten years earlier than Wellington) was challenged to a duel by the radical M.P. George Tierney, following acrimonious exchanges in Parliament. The two men went out on Putney Heath in the early morning, fired their pistols at each other, and fortunately both missed. Humorists of the time had fun by suggesting that Pitt's skeletal frame should be marked in chalk on Tierney's rotund body, with the rule that hits outside it did not count. But King George III was most upset, and Pitt's friend William Wilberforce was furious. Pitt himself, who was under great strain at the time, seems to have been prostrated by the experience, and did not reappear in Parliament for several weeks.

     Wellington's duel came from his change of mind over the great question of Catholic Emancipation in Ireland. The Tory Party had long been split over the issue, and Wellington had taken the Premiership in 1828 as an opponent of emancipation. The position was that Catholics could vote, but under the Test Acts passed back in the 1670s could not sit in Parliament. This issue came to a head in 1827 when the Irish Catholic leader Daniel O'Connell overwhelmingly won a by-election in County Clare. Wellington, as the son of an Irish Protestant noble family, might have been expected to lead a movement to deny O'Connell his seat, but that did not happen. In war, Wellington had always preferred to retreat rather than fight what could prove to be a losing battle, and he particularly dreaded the risk of disorder and civil war. He had been serving in India during the terrible events of 1798 in Ireland, when many thousands had been killed in an unsuccessful rebellion, but it would have been foremost in his mind. He therefore changed course completely and introduced a Catholic Relief Bill in 1829, permitting Catholic representation.
     His more extreme Tory colleagues, nicknamed the "Ultras", were both bemused and horrified. Lord Winchilsea was one of these. The incident which provoked the duel was, however, a comparatively trivial one. Wellington had made a substantial financial contribution to the establishment of King's College, London, and there had been fears that the new college would have no place for religious instruction. Winchilsea, who was clearly not very intelligent, accused Wellington of harboring "insidious designs for the infringement of our liberties, and the introduction of Popery into every department of state". He suggested that Wellington had "disgraceful and criminal" motives.
    Wellington was naturally furious, and his temper was not improved by receiving from the Bishop of Salisbury scathing letters denouncing his policy. He wrote to Winchilsea demanding an apology, and when this was not forthcoming, issued a formal challenge to a duel: "I now call upon your Lordship to give me that satisfaction which a gentleman has a right to require, and which a gentleman never refuses to give". A duel was accordingly arranged. Wellington's old army comrade Sir Henry Hardinge acted as his second, with Lord Falmouth acting for Winchilsea; and Wellington's doctor, John Hume, was also asked to attend, bringing a pair of pistols.
     The two parties met at Battersea Fields early on Saturday morning. Wellington intended to hit Winchilsea in the leg, but missed. Winchilsea fired in the air. He then produced a letter of apology, which however Wellington considered unsatisfactory. The two then parted on coldly formal terms.  
      Wellington was deeply angered by the whole affair, and his irritation would only have been increased by receiving from Jeremy Bentham, the founder of the philosophy of Utilitarianism and advocate of reform, a letter berating his conduct, beginning with the words, "Ill-advised man!"

This cartoon of the duel is by "Paul Pry". The sign in the background reads, "Battersea Shooting Grounds Grand Pigeon Match". Wellington is dressed as a monk, complete with a rosary, and his head is transformed into a lobster's claw. He is saying, "I used to be a good shot but have been out of practice some years". Winchilsea is saying, "I'll make myself up small - Gad if he should hit me - I might be tainted with some of his Popery - wont give him more than one chance".

The next cartoon places the duel in the context of the ferocious disputes of the time.
It shows Wellington and his Home Secretary, Robert Peel, in the act of "Burking poor old Mrs Constitution, aged 141". This refers to a sensational murder trial earlier in the year, when William Burke and William Hare and their wives were convicted of smothering lodgers at their Edinburgh doss-house and selling the bodies to Doctor Knox at the university for dissection. "Mrs Constitution, aged 141" refers to the overthrow of James II in the "Glorious Revolution" of 1688, since when it had been illegal for any Catholic to ascend to the throne or to hold government office. The writing above the picture reads, "Hark! the Doctor Knoxcks - she is almost done and ready for you". The "Doctor" entering is a Roman Catholic bishop. The message is clear: Wellington and Peel are about to betray the country to the Catholic church.

Despite these libels, the Catholic Relief Bill passed the House of Commons with a large majority at the end of March 1829. The opposition Whig party was strongly in favour of the measure, though very many Tory "Ultras" voted against. Wellington expected more problems in the House of Lords, but he delivered one of his best speeches, arguing that there was a straight choice between reform and civil war, and won with majorities of over 100 in the various divisions. Next he persuaded or bullied the timorous and tearful King George IV (whose health was now extremely poor) into signing the Bill into law. Catholics could now sit in Parliament. It is very doubtful whether anyone other than Wellington would have had the prestige to have carried it through.
    The Ultras never forgave him for what they saw as a gross betrayal. The pathetic King died in June 1830. There was then a general election, in which the Tories lost ground. In November the Ultras voted with the Whig opposition to defeat the government in the House of Commons. Wellington could perhaps have soldiered on, for it was not in his nature ever to give up, but he had had enough of party politics, which he had never understood (so different from commanding the army, when his orders had been obeyed without question!), and he decided to resign. A Whig government took over, and embarked on a campaign to reform the whole system of Parliamentary representation; a reform which Wellington had always totally opposed.

Saturday, 9 May 2015

Ypres and Bruges

Ypres and Bruges, together with Ghent, in the region traditionally known as Flanders, were important towns from early in the Middle Ages, flourishing particularly from the cloth trade with England. In the fifteenth century they provided the wealth for the magnificent Duchy of Burgundy. In the sixteenth century they passed under the control of Spain, and in the eighteenth formed part of the Austrian Empire. But by this time they had fallen behind economic and social changes, with the fortunate result that their splendid mediaeval centres remained largely unaltered. In 1830 the Kingdom of Belgium was created, which in 1914 suffered the great misfortune of being the highroad by which the German army planned to crush France.

The First World War left Bruges and Ghent untouched, but this was not the case with Ypres. It had the misfortune that for four years it was right on the front line between British and German forces. The town was under constant bombardment and was the focus of major battles in 1914, 1915 and 1918 (the last commonly known as the battle of Passchendale: a village to the north-east of Ypres). As a result, Ypres was completely destroyed; its splendid ancient buildings laid waste

The only parts to survive were the 17th century defensive walls, built by Vauban for Louis XIV. These provided the best shelter for the British headquarters staff.

After the war the magnificent Cloth Hall, which was built in the 13th century, was reconstructed as a
faithful copy of what it had been. So was the rest of the town centre. The "Great Market" by the Cloth Hall is now a parking area for tourists. St. George's chapel nearby contains memorials to the British army. There is an excellent military museum.

The most famous modern building in Ypres is the Menin gate, at the eastern entrance to the town. It was completed in 1927, and is inscribed with the names of more than British and Empire soldiers who have no known grave.

Buglers sound the Last Post there every evening, and wreaths are laid.

Bruges ceased to be a major trading city when its outlet to the sea, the river Zwin, silted up late in the 15th century, and in consequence its centre has hardly been touched by modern developments. It is a city of canals

The centre is dominated by the magnificent 13th century octagonal tower of the Belfort. It faces the old market place, which is remarkable for its stalls selling First World War relics.
It is well worth climbing the tower, because there are splendid views over the town.

There are too many fine mediaeval municipal buildings and churches to be all mentioned here, but among the best are the basilica of the Holy Blood

and the City Hall.

There are also grand tombs and art from the Flemish Renaissance; but I particularly liked this charming old wall-painting.

The two cities should be visited together, perhaps on the same day, to enable you to wonder what Ypres might have looked like if it had been more fortunate a hundred years ago.