Clean fight
If it is true that peregrines are such voracious eaters of pigeons (Letters
16 December, p 52, and 13 January, p 47), I wonder if they could be introduced
into central London to clean up the streets?
It might be upsetting the balance of nature, but this has already been
upset by the many tourists and residents who encourage these airborne rats by
feeding them.
Flexitime
Michael Pinder (Forum, 10 February, p 45) advocates several major changes
to our clocks and calendars, none of which is original.
I applaud his suggestion that we should adapt our working hours to the
hours of daylight, rather than the clock. While Global Time would remove the
need to change our watches as we travel east or west, it carries the
inconvenience that 1200 hours would mean midday in London, but early evening
in Singapore. Totally impractical, however, is the suggestion that the date
should change worldwide at Greenwich midnight. Come mid-afternoon, in Los
Angeles, Thursday the 15th would suddenly become Friday the 16th, so what
would we mean by “see you next Thursday”? The concept that the hours of
daylight constitute one day is surely inviolable. That said, astronomers do
use Universal Time – effectively Greenwich Mean Time – the world over, for
their records.
Astronomers also use Julian Date, which is simply a count of days from an
arbitrary base date, 1 January 4713 BC. Each Julian date starts at midday GMT
wherever the observer may be, and times within the day are indicated by
decimal fractions, much as Pinder suggests. The Julian Date is now 2450126.07,
which is much simpler than “12 February 1996 at 1.40 pm GMT” but is far less
meaningful.
In everyday life we need years, months (and weekdays) to understand quoted
dates, but the system could be simplified. Pinder’s proposed year of 360 days
plus five or six public holidays implies twelve 30-day months, each of which
could be divided into three 10-day weeks. This system was devised by Thoth in
Egypt around 3000 BC. Thoth’s Calendar was revived briefly during the French
Revolution and survives today, essentially unchanged, in the form of the
Coptic Calendar, used in parts of Egypt and Ethiopia.
The ancient Egyptians also used decimal time, as Pinder proposes – each day
had 10 “hours” of 100 “minutes” each of 100 “seconds” – they counted seconds
by feeling their pulse.
As someone afflicted by fractional time-zones (Colombo is GMT + 5
hours) I applaud Pinder’s suggestion that we should do away with them
altogether. When this idea was proposed about thirty years ago in an American
aerospace magazine, an interesting refinement was added. We should also switch
from solar to sidereal time – only 4 minutes difference, but during the year
the Sun would go right round the clock, so everyone would have an equal share
of it.
As for “real” calendar reform, desirable though it is, that will have to
wait until the year is an exact multiple of the day. A nice challenge for the
engineers of the rather far future …
Earthy vibes
The cause of vibrations felt on touching electric jugs and electric
blankets (Letters, 10 February, p 48) can hardly be electrostatics,
considering the minute field strength expected in these circumstances. Surely
the effect arises from the interaction of the Earth’s magnetic field and the
alternating current in the elements? A common school science demonstration
involves moving a powerful magnet towards a light globe, causing the filament
to vibrate dramatically and eventually break.
Long live Morse
Alex C. Morris is largely correct in his political and commercial
assessment of the value of Morse code. However, he may be premature in
publishing the obituary (Letters, 17 February, p 50).
Morse remains popular among radio amateurs for two reasons. First, it
allows people onto the air for minimal investment; and second, its narrow band
width allows slow but effective contact in noisy and overcrowded
conditions.
Fuel gauge
The excellent Inside Science “Fuelled for Life” (13 January) contained two
errors. On page 2, column 2, lines 22 and 24 both should read “mole” not
“molecule” – the difference being the Avogadro number 6 脳
1023.
Water, water …
According to your article on freezing brackish water (Technology, 20
January, p 19), brine produced by drilling for oil and gas can be purified
using a freezing technique. But this idea is not new. A similar system is in
use elsewhere in the US. And even here, in Ontario, the system is to be
applied to the Upper Rideau Lake.
Uplifting
Timothy Jenson’s confusion (Letters, 6 January, p 44) as to how aircraft
wings work was answered by C. M. Davies (Letters, 27 January, p 51). But now
Philip Mulholland (Letters, 24 February, p 53) claims that Jenson was
right.
He was not, so what was wrong with Mulholland’s experiment with a
descending flow of water applied to only the back of a spoon and obtaining an
obvious force? Simply that this is not the way a wing obtains lift, which
depends on there being flow on the upper and lower surfaces. Mulholland’s
experiment is, in fact, a good demonstration of a rather different phenomenon
which bears the name of its discoverer, Coanda.
The Coanda effect causes a fluid jet, directed tangentially at a curved
surface, to stick to it and to turn with the surface if it is rotated. It is
exploited in blown flaps, in which air from an aircraft engine’s compressor is
blown through a slot over wing flaps to increase effectiveness. If Mulholland
rotates his spoon under the tap, it should show this effect nicely. Mulholland
is wrong when he asserts that there is no pressure acting on the bowl surface
of his spoon when its back surface is held against a falling water stream. The
surrounding air transmits local atmospheric pressure onto the bowl surface but
the falling water flow transmits a much reduced pressure to the back surface.
This generates a lift force which easily overcomes the horizontal component of
the force exerted on the spoon by the water itself.
Of course, full atmospheric pressure acts on the water stream. This adds a
horizontal component of momentum to the flow, but does not deflect it
sufficiently to follow the curvature of the spoon. Instead the falling water
stream retains the horizontal deflection, which is the equivalent of downwash.
Exactly the same mechanism applies when the flowing “liquid” is the forced
airflow over the surfaces of a moving wing, and lift is generated from the
resulting pressure differential.
Regarding the ability of inverted wings to generate positive lift, as
discussed by Timothy Jenson this results from operating the wing at a
different angle of attack from the right-way-up mode, but the pressure
differential mechanism still applies. However, upside-down wings are less
efficient than those the right-way-up, generating significantly less lift and
a
slower rate of climb for the same airspeed with optimum flight geometry.
Upside-down aircraft have to go faster in level flight than their right-
way-up cousins, unless the right-way-up wing is deliberately used with an
inefficient flight geometry.
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Random numbers
It is depressing that only a small proportion of lottery players attempt to
choose their numbers rationally (This Week, 24 February, p 14), though perhaps
not surprising given the irrationality of gambling in most circumstances.
It’s rather more depressing to find your distinguished journal unable to
understand why rational considerations are relevant to the choice of lottery
numbers: it is difficult to tell whether this error is your own or is taken
from the sociologist whose work you reported.
Of course, each possible set of numbers should have the same probability of
winning, but which set you choose can make a considerable difference to how
much you will win if your set of numbers (or most of them) does came up. This
is because there are popular sets of numbers – sets that are easy to mark on a
ticket, last week’s winning numbers, numbers between 1 and 31 (because of the
tendency to choose special dates), and so on.
Evidence of the importance of this fact was provided in the week when 133
people shared the UK lottery jackpot – an event of vanishingly small
probability (around one in 1080). More subtle evidence can be seen
in successive “double rollovers” This was headlined in some papers as “an
event that should only occur once in 400 years”, but is really just evidence
that the sets of numbers people choose are not spread randomly among the
possible sets.
Thus it is rational to try to avoid popular sets of numbers. A simple
strategy is to use a random number generator. A more sophisticated one would
be to try to identify some large class of unpopular numbers – numbers likely
to cause a rollover – and choose randomly from among these.
Doctored photos
I am a wildlife cameraman and conservationist and, ever since image
manipulation became a simple process, I have been concerned about people
misrepresenting the natural world.
I was therefore extremely dismayed to see that New 杏吧原创 fell into the
trap. Your 17 February issue carries an article on “the desperate plight of
the cheetah”, accompanied by a photo of a cheetah chasing an antelope (“A
strategy for survival”, p 14). Some time ago the British Journal of
Photography published the same photo in an article on image manipulation. It
turns out that the image was created out of five different photos and three
different animals, the natural movement of the cheetah (and the sex of the
antelope) being distorted in the process. Already people are losing touch with
the natural world. But this will accelerate, especially if doctored
photographs of wildlife are used as if they were real. It would be a shame if
we were to lose the cheetah as a species and could not even be sure of what it
looked like.
Smart adverts
Neil Barrett is a consultant in the social implications of technology and
is based in Hemel Hempstead. Presumably in same sort of cave in Hemel
Hempstead if his article about “smartverts” (Forum, 17 February, p 44) is
anything to go by.
The discussion of the Guinness screensaver achieved something very rare for
a New 杏吧原创 article (Feedback excepted) – it made me laugh out loud.
Barrett is apparently “sure that Guinness had nothing to do with its release”.
I, on the other hand, am certain that they and their advertising agency,
Ogilvy & Mather, were directly responsible for it.
The in-depth research I undertook to find this out consisted of installing
the program on my PC. I was given a text file to read, telling me in no
uncertain terms that “Guinness” and the harp logo are trademarks, and that the
screensaver was written by NoHo Digital for Ogilvy & Mather and Guinness
brewers. Just in case you don’t know where to find this “escaped” advert, the
television advert now always shows the Web address where it is to be found.
Hardly the example of spontaneous underground pirate advertising it is made
out to be.
So, is it in fact a case of a brewery (or more accurately their advertising
agency) inventing a whole new form of advertising? Not really. Computer
screens, and in particular computer game screens, have been advertising for
some time.
Barrett invites us to imagine playing Doom against a backdrop of
advertising hoardings. l invite him to imagine a fastfood company taking a
popular arcade game and making minor cosmetic changes to the graphics so that
they are recognisably those used in its television advertising campaign.
Further the company includes a routine to play the advertising jingle
continually while the game is being played, and then sells the game through
one of the largest software companies in the country into a market made up
almost exclusively of schoolchildren. I give you – “Mr Wimpy”, released in
1983 for the Sinclair ZX Spectrum.
This “gamevert”, which was a direct “adaptation” (copy) of the Williams
arcade game Burger Time, sold several thousand copies. Given the computer
culture of the time, I would estimate that for each copy that was sold, a
further four were “pirated”.
Before and since, companies large and small have paid highly to place their
products in computer games. Examples include McDonalds, Virgin, ZTT Records
and Frankie Goes to Hollywood, and countless “tie-ins” with films and
television programmes.
Barrett has apparently failed to notice this advertising because the
advertisers have wisely been careful to target them at the market they are
trying to reach, namely the young. Only recently have enough adults begun to
spend enough leisure time using computers to make it worth directing adverts
at them.
Lorenz's legacy
Undoubtedly, Konrad Lorenz was an inspiring man and a great man too.
However, in science one should neither exaggerate nor fall into a personality
cult, as Aubrey Manning does (Review, 10 February) and as many others have
done before him.
1. It was not Lorenz but Oskar Heinrath who was the real founder of
ethology (particularly his Ethologie und Psychologie der Anatiden, 1910, a
comparative analysis of the behaviour of swans, geese and ducks; and many
other works). Manning overlooked this.
2. I disagree with Manning that Lorenz “was a genius at observation”. What
he had written in 1935 about the non-learning of being fed in cormorant
nestlings and about the pair-formation of herans was factually wrong,
according to my own field studies. When in 1937 I told him about my deviating
observations he simply answered “Das kann man ja kaum glauben” (One can hardly
believe that). Some colleagues had similar experiences. Remember his
misinterpretation of the dog as a descendant of the jackal, against all expert
opinions.
3. It is interesting to learn from Manning’s review that Lorenz developed
his “psychohydraulic model” of instinctive patterns after 1944. That was
several years after I had illustrated my concept of displacement activities
with a hydraulic analogy.
Until at least 1937, probably 1940, Lorenz had stuck to the idea that each
instinctive motor pattern was activated by its own biochemical stimulus
production. At that time my thinking, on the contrary, was guided by the
McDougallian and Freudian concepts of a flow of mental/neural energy from such
major instincts as hunger, sex, fear, etc – an idea which had been rejected by
Lorenz. With my background it was relatively easy to explain out-of-context
activities (including their hierarchical organisation and the vice-versa
principle) by a displacement of the flow of energy. One wonders why it took
Lorenz so much time to develop his “psychohydraulics”, after his acceptance of
the displacement principle. Was it his emotional response to McDougall’s
works?
4. Manning underestimates Lorenz’s political sympathies. These were already
well-known in the late 1930s. In 1937 Lorenz had a political clash with the
once Protestant, then Catholic Dutch animal psychologist Buytendijk, without
being aware that it was Buytendijk.
Later, referring to this discussion, he called his opponent “a Jewish
gentleman” (Bierens de Haan). That was some years after the ousting of Jews
from commerce, public service, universities and other professions in Germany
and after the public burning of books written by Jews. In September 1939, when
Germany started World War II, I withdrew my paper on displacement activities
from publication in the Zeitschrift fu篓r Tierpsychologie and wrote to the
editor Lorenz that I did not want to publish it in what I called an
“aggression state”. He replied that I should publish it in Balinese. Finally,
in 1940 he wholeheartedly endorsed “die rassische Grundlage unserer
Staatsform” (the racial foundation of our form of state). This is quite
different from Manning’s interpretation that the paper “seemed to hint at
approval for Nazi racial policies”.
Of course, Lorenz was in many respects a great man. This should, however,
not be a reason to gloss over his scientific weaknesses and his human
faults.
Clear as mud
Uniquely among the reports I’ve seen, New 杏吧原创 distinguishes the wheat
of US plutonium imports from the chaff of US plutonium exports (This Week, 17
February, p 6). Your article muses: “Why the US took so much British plutonium
is unclear”. Maybe I can help.
British plutonium was exported under an agreement signed in 1959. In 1958,
the US Congress held a hearing on the matter in which a witness stated: “They
[the British] have under construction civilian power reactors … It is the
plutonium from these reactors that there is the possibility of the United
States purchasing …”
In the event the plutonium was bartered rather than sold, thereby partially
avoiding the stigma of “selling plutonium for weapons”. As to the use of this
material, General Starbird testified: “… any plutonium we can lay our hands
an in the longer range when it becomes significant can be used to definite
military advantage.”
Similarly, Senator Bricker asked: “Have we produced and are we producing
enough plutonium in this country [the US] to anticipate all of your needs for
weapons?”
Commissioner Vance: “Some of us think we are not.”
Chairman Durham: “We think so too.”
Does that help to answer your question?
Hidden overheads
Valid or not, Denis Henshaw’s revealing electromagnetic field research
(This Week, 17 February, p 4) only addresses one (albeit critical) part of the
social costs of pylons and transmission lines. Other costs are being inflicted
much closer to home.
Canadian research has shown recently that living within 100 metres of high-
voltage lines (more than 69 000 volts) knocks around 拢2800 off house
prices, while the combined effect of pylon visibility and line proximity
reduces values by around 拢3000. Similar research has yet to be carried
out in Britain, but based on figures in your article, 23 500 homes in Britain
lie within 50 metres of 275 000 volts or more, producing potential costs of
more than 拢70 million.
Could it be that factoring these potential liabilities into the costs and
benefits of transmission planning might just tip the balance in favour of
laying underground cables, even without the health risk?
Circular argument
When I read your editorial claiming that few maths students could solve the
problem of finding the area of a chord of a circle, I was quite dismissive of
it (11 November 1995, p 3). The problem was a trivial one, taking a minute or
so to solve.
But I took your problem and posted it in my office. I work with a highly
qualified and highly respected group of computer scientists. I was quite
amazed and appalled by the result. It had became quite clear by the end of the
day that only a small proportion of people could solve the problem, at least
easily. And curiously, those who could solve it easily were mainly older
people who had not done any school maths for more than twenty years.
In my search far an explanation, I concluded that modern school
mathematics, which teaches “investigation” as part of the curriculum, is
failing to teach “problem solving”. Many of the basic skills and tools used to
solve problems, such as simple algebra, geometry, proof, etc, are being last.
On examining school textbooks, I find that they are oriented towards self-
teaching through investigative steps, but lack any formal consolidation of
results. In some cases, I felt that they would only muddle and confuse pupils,
rather than offer solid mathematical foundation.
I plan to send your problem to colleagues in the US to see what they make
of it. Their school mathematics syllabuses are more traditional. The outcome
will be interesting.