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Overview
This entertaining and informative book tells the dramatic tale of explosives from gunpowder to the H-bomb. Laying the emphasis on the lives of the people involved, on the diverse uses of explosives and on their social and historical impact, the author relates a story of remarkable international and human endeavour. Many of those involved - Roger Bacon, Guy Fawkes, Alfred Nobel, Robert Oppenheimer - are famed worldwide; others, such as C F Schonbein, William Bickford, Sir Frederick Abel and Charles E Munroe, though less well-known, also played critical roles. Alongside their achievements, this book highlights the uses and impact of explosives in both war and terrorism, and in civil engineering, quarrying, mining, demolition, fireworks manufacture and shooting for sport. In many cases explosives are seen to have had a significant historical impact as, for example, in the early use of gunpowder in the American Civil War, the defeat of the Spanish Armada, and the worldwide opening up of canals and railways.
Product Details
| ISBN-13: | 9780752476148 |
|---|---|
| Publisher: | The History Press |
| Publication date: | 11/08/2011 |
| Sold by: | Barnes & Noble |
| Format: | eBook |
| Pages: | 288 |
| File size: | 3 MB |
| Age Range: | 18 Years |
About the Author
Read an Excerpt
Explosives
History with a Bang
By G.I. Brown
The History Press
Copyright © 2011 G.I. BrownAll rights reserved.
ISBN: 978-0-7524-7614-8
CHAPTER 1
The Invention of Gunpowder
Fire can cause so much damage and create so much confusion, chaos and terror that it is not surprising that the use of incendiaries in warfare dates back to very ancient times. Fire-pots being thrown down on troops besieging a town are depicted in Assyrian bas-reliefs in the British Museum, dated around 900 BC, and early writers give detailed, and sometimes lurid, accounts of the use of incendiaries. Herodotus describes how arrows tipped with burning tow were used in the capture of Athens in 480 BC, and Thucydides tells how a huge bonfire was lit against the wooden walls of Platea, in 429 BC. Even more remarkably, he describes the use of a blow-pipe in the attack on Delium in 424 BC:
They took a great beam, sawed it in two parts, both of which they completely hollowed out, and then fitted the two parts closely together again, as in the joints of a pipe. A cauldron was then attached with chains to one end of the beam, and an iron tube, curving down into the cauldron, was inserted through the hollow part of the beam. Much of the surface of the beam itself was plated with iron ... When this machine was brought up close to the city wall, they inserted into their end of the beam large bellows and blew through them. The blast, confined inside the tube, went straight into the cauldron which was filled with lighted coals, sulphur and pitch. A great flame was produced which set fire to the wall and made it impossible for the defenders to stay at their posts. They abandoned their positions and fled; and so the fortification was captured.
At first, almost any locally available materials which would burn were used as fuel but, with time, an unusual degree of sophistication crept in. A collection of supposedly contemporary recipes reveals a whole catalogue of witches' brews. 'Another kind of fire for burning enemies wherever they are can be made', we are told, 'by taking petroleum, liquid pitch, and oil of sulphur. Put all these in a pottery jar buried in horse manure for fifteen days. Take it out and smear with it crows which can be flown against the tents of the enemy. When the sun rises and before the heat has melted it the mixture will inflame. But we advise that it should be used before sunrise or after sunset.' In Arabian manuscripts, the unfortunate crows were apparently set on fire before launching; similar use of fire-birds appears in early Chinese works.
There were many other horrible formulations, all trying to outburn the others, but the use of incendiary materials entered a new phase in AD 673 when an architect called Kallinikos carried the secret of Greek fire from Heliopolis to Constantinople. That majestic city was the centre of the Byzantine Empire and Greek fire was to be the lynch-pin of the empire's successful defence, against attacks from all quarters, for the next 800 years. It was an embryonic napalm, the Palladium of the Empire and, without doubt, the greatest deterrent of the day.
But quite what Greek fire was must remain something of a mystery. The name itself is widely used, or misused, for almost any incendiary mix, and may be used synonymously with wild-fire, wet-fire, sea-fire, maritime-fire, automatic-fire or incendiary oil. In Britain, where the incendiary was first introduced towards the end of the twelfth century, the term wildfire was generally preferred, and has remained in usage in the phrase 'to spread like wildfire'. The fact that Greek fire did spread very rapidly over the surface of water gives some indication of its nature. It was always described as a liquid or semi-liquid material; it could be propelled through tubes; it floated on water; it was very difficult to extinguish; and it was possible, somehow, to keep the secret of its manufacture within Constantinople for many years. The secret was, indeed, very well protected by the Official Secrets Act of the day. The Emperor Constantine VII decreed that enquirers were to be told that it had been revealed by an angel, and there were very stern warnings that any communication of it to the enemy was treasonable and sacrilegious, bringing with it divine retribution. Someone about to betray the secret, it was said, had been struck by lightning.
What was the secret? All the evidence suggests that the main component of Greek fire was made from rock-oil or naphtha. This is a black, sticky material which does not occur at all commonly on the earth's surface but which is found, oozing out of the ground or floating on pools of water, in the region between the Black Sea and the Caspian Sea. Rock-oil does not burn very easily, nor is it a very good solvent. But, if it is distilled – and the great secret was probably how to do this safely – a lighter, more inflammable oil can be obtained. It was probably an oil like this, thickened by dissolving in it such substances as sulphur and resin, that made up Greek fire. An early recipe says 'You will make Greek fire in this way. Take liver of sulphur, tartar, sarcocolla and pitch, boiled salt, petroleum oil and common oil. Boil all these well together. Then immerse in it tow and set it on fire. If you like you can pour it through a funnel. Then kindle the fire, which is not extinguished except by urine, vinegar or sand.'
On land, Greek fire was either hurled from ballistae in large tubs with the mixture already alight, or projected in pots and then ignited by incendiary arrows. At sea, it was ejected through tubes or siphons. An account of a naval battle between the Greeks and the Pisans in 1103 gives a good, general picture but is very short on technical detail. 'Each of the Byzantine galleys', it says, 'was fitted in the prow with a tube ending with the head of a lion or other beast made of brass or iron, and gilded, frightful to behold, through the open mouth of which it was arranged that fire should be projected by the soldiers through a flexible apparatus.' It is not at all clear how all this could have been achieved in practice. Playing with fire is a dangerous business and the player can easily get his own fingers burnt. Nevertheless, the problems must have been overcome successfully, because Greek fire served the Byzantines extremely well. The empire flourished, in all, for eleven centuries and only fell in 1453, when the Greek fire was overpowered by the relatively newfangled gunpowder of the Turkish invaders.
* * *
For many hundreds of years, until well into the second half of the nineteenth century, gunpowder was the only explosive to be used both as a propellant in guns and for blasting in warfare, mining and civil engineering. It only began to lose its monopoly when so-called nitro-explosives, such as dynamite and guncotton, were discovered around 1850.
As it looks rather like soot, gunpowder is commonly called black powder. A typical modern sample contains 75 per cent of potassium nitrate (nitre or saltpetre), 10 per cent of sulphur and 15 per cent of wood charcoal (carbon), but early mixtures contained much smaller amounts of saltpetre. All three components must be finely powdered, and they must be well mixed.
Sulphur is a yellow solid which will burn in air with a rather feeble blue flame. Wood charcoal simply smoulders, as in a barbecue. Both will burn much more rapidly in an oxygen-rich atmosphere, particularly if they are finely powdered, and it is the potassium nitrate that holds the key to gunpowder because it provides the oxygen. When gunpowder, or black powder, is lit, the oxygen from the nitrate enables the sulphur and the carbon to burn rapidly, forming a mixture of hot gases containing mainly sulphur dioxide and carbon dioxide, so that there is a large, and rapid, increase in volume. But this will only lead to an explosion if the gunpowder is lit in a confined space such as a sealed container, a gun barrel or a borehole, so that the pressure can build up sufficiently.
The pressure rise with gunpowder is never as dramatic as it is with high explosives, such as dynamite or guncotton, and it is classified as a low explosive. It is not very effective in cutting through steel plate, but it is suitable for pushing projectiles out of gun barrels, or blasting rock when it is set off in a borehole. It is referred to as a propellant explosive to distinguish it from high explosives which have a much greater shattering effect. Dynamite delivers a knock-out blow; gunpowder gives a more prolonged, steady push.
Gunpowder is easy to handle, easy to set off (it only requires to be heated above 300°C) and very safe, so far as any explosive can be regarded as safe. If lit in the open it simply burns away very quickly, even in the absence of air. The major disadvantages are its lack of power, its production of a lot of nasty smoke and fumes when it explodes, and its failure to explode when it is damp. In the early days, setting off gunpowder always involved some sort of heat or fire – a hot rod, a flame, a spark or frictional heat – and the use of the word 'fire' has persisted in 'fireworks', 'gunfire' and 'firing the gun', even though modern guns are generally set off by the explosion of a very sensitive chemical by a sharp blow, or percussion, as in a child's toy cap-gun.
* * *
Gunpowder is both the best known and the oldest explosive, but its origins are shrouded in some mystery. Any researcher is soon entangled in a web of mistakes, misinterpretations and misrepresentations and the chance of finding a definitive answer has always been rather bleak. But a few historians have continued the search, sifting through claims that gunpowder was first used in Persia, in India, in Arabia, and in China. The most authoritative modern view is that gunpowder was first made in China, in the middle of the ninth century AD, by Thang alchemists who were actually looking for the elixir of immortality – one of the most remarkable examples of inventing one thing while trying to find something else. The early Chinese literature refers to 'fire-chemical' and 'fire-drug', but it is not until 1004 that there is any specific mention of the composition of gunpowder and even then no information is given about the proportions in the mixture.
The earliest use of gunpowder was certainly in fireworks, for which the Chinese have always had a passion, but the possibility of making simple bombs and grenades was realized during the eleventh century. The military implications led the Chinese to place the production of sulphur and saltpetre under state control and in 1067 the emperor banned their sale to foreigners. The Chinese army was already well over a million men strong and it was necessary to arm it as well as possible to fend off attacks by the Mongols from central Asia.
No one knows with any certainty how the news of all this remarkable activity in the East reached the Western world, nor why it travelled so slowly, but it may have been carried by the Saracens – those middle-men between the Orient and the West – for Roger Bacon, who first told the tale in about 1260, could read Arabic.
* * *
Roger Bacon was born in 1214 at Ilchester in Somerset. An inscription placed in the Church of St Mary Major there 'by a few admirers of his genius' to commemorate the seventh centenary of his birth gives a sketch of his life and achievements. It reads:
To the immortal Memory of Roger Bacon, a Franciscan Monk and also a free enquirer after true knowledge. His wonderful powers as mathematician, mechanician, optician, astronomer, chemist, linguist, moralist, physicist, and physician gained him the title of Doctor Mirabilis. He first made known the composition of gunpowder, and his researches laid the foundations of modern science. He prophesied the making of machines to propel vessels through the water without sails or oars; of chariots to travel on land without horses or other draught animals; of flying machines to traverse the air. He was imprisoned, starved and persecuted by the suspicious ignorance of his contemporaries, but a fuller knowledge now acclaims and honours him as one of the greatest of mankind. Born at Ilchester in 1214. Died at Oxford in 1292.
The sentiments, as in many church inscriptions, may be a little fulsome, but there can be no doubt that Roger Bacon was a very learned and very unusual man, though he remains something of an enigma to historians. Some rate him as heralding the dawn of modern science almost single-handed amid the gloom of the thirteenth century; others have regarded him as a sorcerer and necromancer whose reputation hangs only on legend.
Little is known of his boyhood but he came from a wealthy family who, later in his life, sacrificed their fortunes to help King Henry III in his struggle with the barons. Roger was a pupil of Robert Grosseteste at Oxford, where he studied theology, geometry, arithmetic, music, astronomy, Greek, Latin and Arabic. After some time at the University of Paris, where he graduated so brilliantly that he was nicknamed 'Doctor Mirabilis', he returned to Oxford and became a Franciscan friar around 1250. He lived at a time when learning, independence and freedom of speech were not greatly encouraged, but when a new outlook was being forced on to Western Christendom by the impact of the recently imported translations of major works of Greek and Arabian philosophy.
Bacon, in common with all other Christians of his day, believed that the Bible contained, in one form or another, the whole realm of knowledge. In the preface to his Opus Maius, written at Pope Clement IV's request in an attempt to reassess the changing situation, he states: 'I wish to show that there is one wisdom which is perfect, and that this is contained in the scriptures. From the roots of this wisdom all truth has sprung. I say therefore that one science is mistress of all others, namely theology.' Yet within that medieval concept, he was a great advocate of careful observation and experiment; what would, nowadays, but in a very different context, be called experimental method. He regarded mathematics as the 'gateway and key to all other sciences' and he hoped to demonstrate that natural science, far from being a danger to Christendom, was a source of wisdom and power.
It was the beginning of the Science versus Religion controversy. In all his searchings for the 'perfect wisdom', Bacon applied his famous adage 'sine experimentia nihil sufficienter sciri potest' ('nothing can be certainly known but by experience'). But such a new and independent outlook – not always expressed with great tact – brought him into conflict with other Franciscans, some of whom he attacked as conceited and corrupt pedants. So much so that, in the end, his writings and his freedom were restricted. One report says that Jerome of Ascali, the Minister General of the Franciscans in 1277, 'by the advice of many friars, condemned and denounced the teaching of Roger Bacon of England, master of sacred theology, as containing some suspected novelties, on account of which the said Roger was condemned to prison, with the order given to all the brethren that none should hold his doctrine but avoid it as reprobated by the Order'.
* * *
Bacon revealed the composition of gunpowder in a treatise entitled De secretis operibus artis et naturae et de nullitate magiae ('On the marvellous power of art and of nature and on the nullity of magic'). It consists of eleven letters or chapters, and versions of it are known in Latin, French, German and English, though their validity and the dates of their publication have been much argued by scholars. The work attempts to prove that certain happenings, which at the time were attributed to evil magic, could be due to natural causes and could be imitated by experiment, and it was probably written to defend the author against the charge that he was guilty of magic. Bacon suggests that such unheard-of possibilities as submarines, aeroplanes, compasses, motor cars, suspension bridges and magic lanterns could all be made to exist by natural means and without any trickery at all. This was far advanced for 1260. Yet he is at pains not to reveal any secrets easily. He writes: 'But I recall that secrets of nature are not to be committed to the skins of goats and of sheep [that is, vellum and parchment] that anyone may understand them', and 'a man is crazy who writes a secret unless he conceals it from the crowd and leaves it so that it can be understood only by the effort of the studious and the wise'. And, after explaining seven different ways of encoding secrets, he adds 'I have judged it necessary to touch upon these ways of concealment in order that I may help you as much as I can. Perhaps I shall make use of them because of the magnitude of our secrets.'
(Continues...)
Excerpted from Explosives by G.I. Brown. Copyright © 2011 G.I. Brown. Excerpted by permission of The History Press.
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Table of Contents
Contents
Title,Dedication,
Acknowledgements and Conversion Factors,
Foreword,
1. The Invention of Gunpowder,
2. Making Gunpowder,
3. The Powder Trust,
4. Testing Gunpowder,
5. 'Crakys of War',
6. Mining and Civil Engineering,
7. Gunpowder Modifications,
8. Nitroglycerine,
9. Dynamite,
10. Guncotton,
11. Smokeless Powders,
12. Lyddite and TNT,
13. Setting It Off,
14. Nuclear Fission,
15. The Manhattan Project,
16. Nuclear Fusion,
Appendix I: Names and Formulae,
Appendix II: Energy and Power,
Bibliography,
Copyright,