Gas-Bags

Letters

Vol. 23 No. 23 · 29 November 2001

From Charmian Cannon

Bernard Shaw was not the only one to be excited by the spectacle of a Zeppelin being brought down over Potters Bar, as E.S. Turner writes (LRB, 15 November). My grandmother, who was living in Potters Bar with her family at the time, wrote to her brothers and sisters in September 1916:

It was a still night, clear to the north but misty towards London. We had not been in bed more than an hour, when the sound of gunfire through the rattling of a noisy goods train made me hop up and don a dressing-gown. Poking my head out of the window I beheld to the left a golden Zep being peppered with shells. We congregated in the dining-room and watched from behind the thick curtains. The Zep was turning about, trying to escape. It looked like a great shining fish in the air. At one time it seemed perpendicular. Then it began to come our way and dropped a bomb that shook the house and made the air hit our faces. So we adjourned to the back passage, where the walls are thick and no glass could hurt us. No sooner had we done so when a glare shone through the back door glass panels. 'It's burning!' we cried, and hurried back to the window to see it falling in flames. It looked as if it might fall onto the house but really fell in a field behind the church. Next morning we saw its crumpled remains hanging on a tree … What a horrible fate the Germans send the Zep crews to!

Charmian Cannon
London NW3

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Vol. 24 No. 1 · 3 January 2002

From J.F. Darycott

It would seem, from E.S. Turner's review of Douglas Botting's book on the Graf Zeppelin (LRB, 15 November 2001), that he is unaware of recent research that shows the cause of the Hindenburg disaster to have been the ignition of the highly flammable coating on the outside of the ship's fabric, a coating not applied, if I remember rightly, to the Graf Zeppelin. This coating rapidly propagated flames the length of the vessel, burning into the gas-bags and setting fire to the hydrogen within; but the destruction of the gas-bags would have led just as surely to the loss of their contents, and hence of the ship, if they had been filled with helium.

Hydrogen, while readily flammable, is not, I believe, particularly explosive: certainly not as explosive as petrol, and there is no more (and no less) reason to write of 'hydrogen-filled dirigibles being potential flying-bombs' than there is to write similarly of kerosene-filled airliners or petrol-filled road tankers.

But all this is by the by. What we really want to know is what was Mr Turner doing on the Queen Mary's maiden voyage? Had he paid for a passage? Or was he a journalist on a freebie? What class did he travel? May we have an account of the trip? Indeed, in the absence of Mr Bennett's diaries this year ('nothing much has happened'), perhaps the LRB could fill its blank pages with Mr Turner's reminiscences of the 1930s generally.

J.F. Darycott
Staines, Middlesex

From Jerome Shipman

E.S. Turner wrote that Hugo Eckener wanted the Hindenburg to be filled with helium instead of hydrogen, but American law strictly forbade its export. 'Germany could presumably have produced helium,' Turner continues, 'had the will been there.' The only place helium was produced economically in the quantities the German zeppelins required was America, from wells in Texas, Oklahoma and Kansas. Helium can be extracted from the atmosphere, but it only occurs in the amount of one part in 200,000. In Dr Eckener's time you couldn't get blood from a turnip, and you couldn't get helium from any place but the United States of America.

Jerome Shipman
Potomac, Maryland

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Vol. 24 No. 2 · 14 January 2002

From E.S. Turner

Responding to my review of Dr Eckener's Dream Machine, J.F. Darycott (Letters, 3 January) refers to recent research suggesting that the cause of the Hindenburg disaster was the highly flammable coating on the ship's fabric which resulted in a rapid spread of flames along its length. Douglas Botting, the book's author, mentions this theory, and gives 'discharges of an electrostatic nature' as the initiating agent. I may well have over-simplified in saying that the Hindenburg's nemesis was static electricity. Whether a hydrogen-filled airship was any more of a flying bomb than a kerosene-filled airliner I leave your readers to ponder. Happy air miles!

All this is by the by, J.F. Darycott continues, and then asks, reasonably enough: 'What was Mr Turner doing on the Queen Mary's maiden voyage? Had he paid for a passage? What class did he travel?' In 1936, the year of that voyage, I was on the editorial staff of the Glasgow Evening Times, which contributed towards my tourist-class fare, in return for coverage of what was an important occasion for the Clyde. I had visited New York the year before on my annual holiday (four days amid the skyscrapers, 14 days getting there and back) and had romantic reasons for returning. On the Queen Mary there were scores of more favoured reporters, all as far as I know travelling first class. The passenger list contained entries like 'Miss Frances Day, and chauffeur' and 'The Rt Hon. Lord Inverclyde, and manservant'. In Tourist we dressed for dinner, though this was not our usual custom. Occasionally I slipped along into First, until the entry points were blocked. The voyage was quite uneventful; no stowaways, no icebergs. I made other crossings, notably on German and Italian liners, often returning near-broke and compelled to freelance furiously, not to mention sub-editing football reports on Saturday nights. Those well-fed journeys could be dismayingly dull; possibly the people in Third had more fun. Even Alan Bennett might have been hard put to knock a diary out of life on an ocean greyhound, though I like to picture him as the sole first-class passenger – as occasionally happened on the less popular lines – with a restaurant, a film show and a lifeboat all to himself.

E.S. Turner
Richmond, Surrey

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Vol. 24 No. 3 · 7 February 2002

From Ian Southern

J.F. Darycott (Letters, 3 January) claims that 'hydrogen, while readily flammable, is not … as explosive as petrol.' Many people, fed on Hollywood imagery, believe that petrol is a highly explosive liquid. But that is not the case, as anybody who has seen a match thrown into a bucket of petrol will testify. All that happens is a rather smoky, though energetic, burn. For petrol (liquid at standard temperature and pressure, or STP) to explode, in the sense of a supersonic-type ignition, it needs to be well mixed with an adequate supply of oxygen, which is not easy without some external intervention, for example the mixing of petrol vapour with air in the combustion chamber of an engine. The main problem with hydrogen is that it is a gas at STP and readily migrates, mixing with air as it goes, to places where there are potential ignition sources.

Ian Southern
Soto de la Marina, Spain

From T. Chertsey

Jerome Shipman isn't quite right. Helium is, as he says, present in the gaseous emissions from natural springs in the US, but it is also present in natural gas at levels of 1 per cent. Helium, however, can be obtained from the liquefaction of natural gas. This isn't easy (it doesn't undergo adiabatic cooling on expansion until very low temperatures are reached), but it isn't impossible: the Germans would doubtless have pursued this technique if they had had the will, as E.S. Turner suggests. They could also have obtained helium from monazite sands by heating to 1000°C – the sand was at that time available from Australia.

T. Chertsey
Winchester

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Vol. 24 No. 4 · 21 February 2002

From Rupert Holroyd

What planet is T. Chertsey living on when he says that monazite sands could be a source of helium (Letters, 7 February)? Monazite is extremely radioactive, having principle radionuclides from the thorium-232 series. Thankfully, where monazite does occur in beach sand (in places such as Australia, Brazil, India and China), it does so in such small quantities as not to affect the local populations adversely. Harvesting the sand in sufficient quantities to produce enough helium to fill a flotilla of air balloons would require more radiation suits than any army now could muster, let alone the Army in prewar Germany.

Rupert Holroyd
Twickenham

From Ian Adveron

Airship engineering and the availability of helium were rather more advanced in the 1930s than some of your correspondents may have realised. Extraction of small amounts of helium from monazite sand was underway in Australia before the end of the First World War, but the compressors were not powerful enough to produce the quantities required by rigid dirigibles (the capacity of the modified R101 was 5,508,500 cubic feet). In 1929 RMS Hororata left Fremantle with 23,000 tons of sifted monazite – enough for three R101 round trips to Karachi – bound ultimately for the airship works at Cardington. There a refinery was under construction, intended to become fully operational by 1937. The Hororata docked in Southampton three weeks after the destruction of the (hydrogen-filled) R101 in France. Rather than send the load back to Australia or begin the costly extraction of the gas, the sand was used as landfill in Thanet, among other locations. In the late 1930s another role presented itself: as a filling for sandbags. Those with memories of the war or National Service may recall a slight bronze tint to the sand in some bags which left a reddish stain on the fingers. My father, a chemist with the Ministry of Supply, recalled a rumour that this was because the sand had been brought from military execution grounds. The area of the Tanami Desert in Western Australia where monazite sand occurs is now under the administration of the Karlantijpa North Aboriginal Land Authority.

Ian Adveron
Stirling

From Lavinia Cramer

Let's get this straight. Helium can indeed be obtained from the liquefaction of natural gas, but, despite what T. Chertsey thinks, this doesn't mean that helium itself is liquefied. It is, rather, a product of the liquefaction process – if you boil salt water to get the salt, the salt itself doesn't boil away. So the liquefaction of helium doesn't come into the argument at all: they haven't yet started to fill air balloons with liquid helium.

Lavinia Cramer
Essex

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Vol. 24 No. 5 · 7 March 2002

From Humphrey Fullerton

The radioactivity of thorium, cited by Rupert Holroyd (Letters, 21 February) as making monazite dangerous to process, is largely irrelevant. Monazite is heated to 1000°C to produce helium, but the melting point of thorium is 2000°C, so unless some idiot in the factory suddenly whacks up the central heating, helium production will continue to be as safe as it has been for the last 60 years. In fact, drinking coffee is far more dangerous: the radioactivity produced naturally by coffee beans is measurable without heating the beans at all.

Humphrey Fullerton
Cork

From Stanton Cavendish

Rupert Holroyd takes the line that monazite occurs in such small quantities that it does not harm local populations. This is a grave error to make, and one consistently made by Governments in countries such as Brazil, China and Mexico where it is difficult for local populations to gather the facts themselves. Thorium-232 has a longer lifespan than any uranium isotope: it has a half-life of 14 billion years. Thorium is especially toxic to the liver and spleen, and is known to cause leukaemias and other blood diseases. It decays to produce radium-228, then radium-224, which in turn produces radon gas (radon-220) in greater quantities than the helium found in monazite. Given that it takes just 20 milligrammes of thorium dust to kill an average-sized person within a month (inhalation would do the trick), there is no question that monazite sands present a risk. The danger comes not only from the existence of the monazite in local sands (leukaemia rates are higher in black sand areas where monazite is found), but from its processing, which must be performed in close proximity to the mining site due to the risks of environmental contamination, something that is rarely taken into account when monazite waste is dumped in landfill sites where indigenous populations are housed.

Stanton Cavendish
Richmond, Surrey

From Luc Schokkaert

Contrary to what Rupert Holroyd might think, there is evidence to suggest that leukaemia rates are higher in monazite areas – which is indicative, but not necessarily proof of dangerous levels of radiation. Perhaps the respective Governments of Australia, Brazil, China and India would like to contribute to the discussion by revealing their own reports on blood disease levels in areas where monazite is mined. I am aware of no such report currently circulating from any of these countries.

Luc Schokkaert
Stockholm