The far side
A story in your booklet brought back memories (Bizarre tales from New
杏吧原创, 21 March, p 45).
In the 1970s, I worked for Hawker Siddeley at Hatfield, where the company was
finishing production of the Trident passenger plane and work was well in hand
with the HS-146 (now known as the RJ-100).
We were required to test the resistance of windshields to bird strikes, so I
was dispatched to the local supermarket to buy a number of frozen chickens.
These were fired by a pneumatic gun into the windshield. I often wondered what
the results would have been had we not defrosted the chickens.
Needless to say, as an apprentice I was given the task of cleaning up after
the tests.
Letter
One answer to Wiggs’s question might lie in work done by Barnes Wallis over
thirty years ago. He identified a niche market for a small aircraft that would
not have to compete head-on with larger American planes, and would keep Britain
in the forefront of aerospace technology.
Wallis thought the planes would have to be made of aluminium alloy, weigh no
more than 50 tonnes, and need no more than 500 metres to take off and land. They
should take just three hours to fly from Britain to Australia, but be able to
fly from London to Paris subsonically.
His answer was a lifting-body design with small swing-wings. The fuselage
would be rectangular and double-skinned, eight times as strong as a conventional
“tube” design, and the structural weight only 20 to 25 per cent of the total
takeoff weight. Its aerodynamic form would discard kinetic heat with ease
compared with conventional shapes. It would fly much higher than Concorde.
It sounds like the fantasy of a mad inventor. But Wallis was one of our most
brilliant engineers. So just how good was his design, and how does it stand up
today?
Not boom but bang
Richard Wiggs asks if a new supersonic passenger plane could succeed
(Forum, 14 March, p 55).
It doesn’t deserve to, for one overriding reason鈥攕onic
boom. Memories of Concorde’s test flights over the west coast of Britain during
1971 and 1972 may now be rather dim, so perhaps readers should be reminded just
why the sonic boom is so objectionable.
Far from being a harmless sounding “boom”, at its worst it is a violent
“bang” or “crack”, like a high-velocity rifle shot. As it comes without any
warning, it causes the maximum amount of fright and shock.
Because the shock wave declines much more slowly with distance than ordinary
noise, it covers enormous areas. Shock waves from Concorde’s transatlantic
flights are often recorded on barographs up to 5000 kilometres away, and the
biggest cause of false readings on the British Geological Survey’s seismographs
are shock waves from Concorde.
A handful of Concordes may not be too much of a problem, but 300
“Jumbo-Concordes” would deliver a mind-numbing bang every day to every spot on
the globe, with half a dozen secondary booms, thumps and rumbles thrown in for
good measure. We can avoid most of this by continuing to ban supersonic flights
over land, but what about the creatures out at sea鈥攂irds, whales,
dolphins, turtles, seals, polar bears and so on? They are already suffering from
human activities, do we need to make things much, much worse?
Hear it for the Huli
As an anthropologist who has worked in Papua New Guinea, I must respond to
the use of photographs of Huli people in your article on cannibalism
(“The People Eaters”, 14 March, p 42).
Huli live 300 kilometres to the west of the For茅 people mentioned in
the article, and are as culturally and linguistically different from them as are
the English from, say, Italians. They find cannibalism as abhorrent as Robin
McKie assumes his Western readers do, and there is no evidence that they have
ever practised it. The bones depicted next to the images of Huli men on page 44
are in a kebanda, or ritual site for ancestor worship, in which
cannibalism plays no part whatsoever.
Perhaps because of their distinctive decoration, Huli are portrayed in
Western media as primitive and exotic. They are rarely acknowledged, and even
more rarely derive any benefits from the exploitation of their rich visual
tradition.
Letter
“If your eyes accidentally look in the direction of the Sun, your blink
reflex will usually prevent you from staring too long,” writes Chown. This is
obviously so, except during the partial phases of a solar eclipse.
It is the absence of the blink reflex upon which we normally rely that makes
a partial eclipse so potentially harmful. Although the light level is
sufficiently reduced that you do not instinctively look away, the level of
infrared radiation鈥攚hich does the damage鈥攊s not greatly diminished
and remains dangerously high.
Nevertheless, as Chown remarks, it is easy to overstate the problem, and an
accidental glance by a human or an animal is not going to instantly induce
blindness. It is prolonged staring without a filter that should be avoided.
Now you see it . . .
I was glad to have Marcus Chown profile our Aruban eclipse expedition
(“Total eclipse”, 4 April, p 26).
But one point about viewing eclipses
(Forum, p 51)
needs emphasising鈥攆ilters are needed only for the partial phases before
and after the total eclipse. If you use the techniques described during a total
eclipse itself, you won’t see anything at all.
When you are in the total eclipse shadow, the Sun is entirely covered and
what is left is about the same brightness as the Moon鈥攁nd just as safe to
look at.
Broad Scots
Ben Rudder
(Forum, 4 April, p 52)
is right to bemoan the post-16 divide in
schools, which forces arts students to abandon science and vice versa. However,
this is not, as he says, a problem in British schools鈥攊t is specifically
an English and Welsh problem, caused by the narrowness of the A-level system. In
Scotland, a broad, balanced education has always been the norm, with bright
pupils traditionally taking between one and six Highers in both arts and science
subjects.
Before I went to university to study engineering, my Scottish education gave
me English, French and geography as well as maths, physics and chemistry. Since
moving south, I have been appalled by the narrowness of the choices teenagers in
England are forced to make.
Deadly diesel
It is gratifying to read that the Federal Institute of Occupational Health and Safety
in Berlin found that diesel fumes caused fewer miners to develop cancer than expected
(This Week, 14 March, p 7), but we should not forget that
the key issue for diesel exhaust is the link between particulates and urban
mortality.
This is not a long-term effect. The increased death rate with increased
levels of PM10 is thought to be caused by a biochemical response鈥攖riggered
by the inhalation of large numbers of ultrafine particles, rather than their
chemical composition. We cannot afford to be complacent about diesel exhaust
pollution.
Salmon mussel in
Does no one bother to carry out environmental impact analyses on developments
such as salmon farms nowadays? Rob Edwards’s report on metal pollution from
salmon farms in Scottish sea lochs
(This Week, 14 March, p 12) suggests that if
they aren’t already subject to EIAs, they should be.
Over twenty years ago, I ran a thriving shellfish farming project in
Shetland. At the time, the import of smolts, or young salmon, for aquaculture
was banned. When the ban was relaxed, smolts were imported in huge numbers from
Norway, and salmon farming in Shetland boomed.
The best places for the new salmon farms were near our mussel culture rafts,
since we had taken a lot of trouble to survey sites and find those with good
water circulation and high productivity. Within a few months, our mussels and
oysters became misshapen and started to die. The cause? Tributyl-tin antifoulant
diffusing through the sea lochs from nearby salmon cages.
Now we have copper and zinc, from antifouling compounds and galvanised
components, accumulating in sediments. Standard toxicity tests on metals tend to
be done with the metals in solution rather than as solids in sediments. Such
tests miss the dramatic increases in solubility of the metal salts when oxygen
levels fall鈥攏ear the respiratory surfaces of animals, for example.
The information about potential environmental risks is all out there. Why
does no one seek it out and apply it in the planning process?
Win some, lose some
Terence Kealey describes a “zero sum game” as that where everybody wins and nobody loses
(“Envy”, 28 March, p 26). This is the exact opposite of what “zero
sum” means in game theory. It denotes a “game” where any gain is offset by an
equal and opposite loss by some of the other players. So for every +x
there is 鈭抶, whose sum is 0, hence the term “zero sum”.
Terence Kealey writes: Your correspondent is quite right. I omitted the
prefix “non-” before “zero sum”. Sorry!
Shakespearean tilt
Shakespeare knew all about the annual tilt of the Earth
(Feedback, 4 April).
In Julius Caesar (Act 2, Scene 1), he writes:
Decius Brutus: Here lies the east: doth not the day break here?
Casca: No
Cinna: O, pardon, sir, it doth; and yon grey lines
That fret the clouds are messengers of day.
Casca: You shall confess that you are both deceived.
Here, as I point my sword, the sun arises,
Which is a great way growing on the south,
Weighing the youthful season of the year.
Some two months hence up higher towards the north
He first present his fire; and the high east
Stands, as the Capitol, directly here.
Letter
In the feature “Do portable electronics endanger flight?” in IEEE
Spectrum (September 1996), the reason given for the ban on equipment
containing CD players is that “portable compact disc players have an internal
clock of 28 megahertz”, which “produces harmonics at 56, 84 and 112
megahertz鈥攁nd 112 megahertz is a VHF navigation channel” for aircraft.
Noisy CDs
With reference to Lufthansa’s “weird” ban on CD-ROM drives
(Letters, 28 March, p 64),
the airline is probably extending an existing ban on personal CD
players to computers.
In the only case of interference from personal electronic equipment that I am
aware of, an early CD player jammed the instrument landing system on an airliner
in the mid-1980s. Because CD players are optical devices, some of the cheaper
models did not include any shielding against radio-frequency (RF) interference
from the logic devices in their controllers and were therefore quite noisy in
the RF bands.
Sprocket docket
Your report on the effect of sprocket size on bicycle efficiency
(This Week, 21 March, p 6)
is right, but the explanation oversimplified the process that
makes big sprockets better.
The energy loss comes when the chain links rotate to fit around the sprocket,
and again when the chain straightens on leaving the sprocket. The energy loss
per link is proportional to the tension on the chain and to the angle through
which the link bends. Halving the sprocket diameter doubles both the tension and
the angle, so the energy loss per link quadruples.
However, the power loss depends on the number of links per second that pass
over the sprocket, and halving the sprocket diameter also halves the chain speed
and thus the number of links per second. This means that the power loss is
inversely linear with sprocket diameter, as the article concluded.
Mother's teeth
I was fascinated by the feature on the organisms living in our mouths
(“Open wide, we’re going to explore”, 14 March, p 32).
I breed Shetland sheepdogs, all descended from two bitches. The first had
average teeth, as did all her pups and those of her daughter. The second, while
she had many fine traits, had puppies whose teeth invariably needed annual
professional cleaning from the age of about two years onwards.
I had noticed that this seemed to be an example of inheritance through the
female line only (the pups had bad teeth no matter what kind of teeth the sire had),
but now I’m wondering if fostering puppies on a bitch with excellent teeth might
be a way of keeping the genetic line without the bad teeth.
Anyway, I am passing a copy of the article on to my dog’s long-suffering dentist.
Going round in circles
I would like to know under what name the Library Association’s book of
cataloguing rules is filed
(Letters, 28 March, p 63), and how one could find
such a book in a library in order to learn where to look for it.
Letter
We enjoyed the free Bizarre booklet, from the flying saucers to Dear
Rich Bastard.
But oh no, not nominative determinism again! Rob does not steal from
clergymen; Lucy is not a biochemist and has no interest in glow-worms or their
luciferase enzymes; Philip is not a dentist or wall insulation installer.
For more nominative determinism, see this week’s Feedback鈥擡d
Letter
What is it about nominative determinism that is so fascinating (
Bizarre, p 59)? I cannot resist sending you a few more.
In 1986, I found myself on an oil rig under repair in Hong Kong. At coffee
break one morning, we amused ourselves by reading the local phone directory. We
thought up a silly name, looked it up . . . and found it! With growing
disbelief, we found more and more of them, and after half an hour had to give up
as we were all sobbing with laughter. The ones that stick in my mind were: The
Chiu Fat Bakery, The Win King Optical Company, The Lee Kee Motor Boat Company
and also a Lee Kee Boot Manufactory.
The best of all I saw a few days later on a bus up to the Peak, past the
Ruttonjee Chest Clinic and TB Sanatorium and just before Happy Valley. Across
the road was a huge advertisement for the Tin Lung Motor Company.
In case any Asian readers are offended by this unseemly laughter, I am very
conscious of Mahatma Gandhi’s reply to the question “What do you think of
Western civilisation?” It was: “I think it would be a very good thing.” It takes
very little to tickle the average oil man.
Finally, if any of your readers are thinking of visiting the west of England,
they must visit Bridport. In East Street, above a branch of Wingate the
opticians, is a sign proclaiming the vicinity as “Seymour Place”. And last night
at a concert in Weymouth, I noticed that the theatre’s catering manager rejoices
in the name of Beno卯t Gateau. It’s a wonderful world, isn’t it?
Letter
Newsagents are far too canny to reduce trade by killing their customers. You
can be assured that when I go out of an evening for a spot of homicide, the
safest people are those who buy their New 杏吧原创 from my modest
emporium.
Read all about it
As a newsagent, I am intrigued by the statistic: “0.0003 per cent of all
murders are committed by newsagents”
(Feedback, 4 April).
Is this higher, or lower than average? In other words, should traders be on
their guard for the, say, 0.0004 per cent of dangerous customers?
Then again, with the dismal trend of publications like yours promoting
subscriptions, have you considered the risk of murder by postal workers?