Letters: Hydrogen power
That the annual California market for 100 000 electric vehicles could
also be serviced by hydrogen-powered internal-combustion engines, is apparently
not worth a mention by Geoffrey Howard (‘Flat out for the car of the future’,
7 November). The advantages and disadvantages of both technologies are many
and remarkably similar. Both have giant industrial backers. It is no foregone
conclusion which technology would meet more closely the objectives of environmentalists
and car users.
Roger Lampert Borehamwood, Hertfordshire
Letters: Trolley trouble
I was rather concerned to read about airport luggage trolleys gathering
in a Sussex seaside town, (Feedback, 7 November and Letters, 21 November).
These are not mere artifacts but the migratory phase of a particularly unpleasant
colonial organism.
The best known study of this can be found in Terry Pratchett’s work
Reaper Man. He was studying a slightly different species (the supermarket
trolley) but I suspect the life cycles are very similar.
Do not allow these trolleys to swarm in your town, or they will form
a colony – an international travel terminus.
I hope this warning has come early enough.
Carol Stevenson London
Letters: No distractions
I. J. F. Poplett (Letters, 3 October), does not seem to be aware of
such deaf scientists as the Australian-born Nobel Laureate, Sir John Cornforth
(Chemistry, 1975), who has been deaf since the age of about ten. Deaf people,
scientists or otherwise, have the advantage that noises which would distract
you or me, go over their head – not in one ear and out the other.
R. G. Gillis University of Melbourne Australia
Letters: Exploding 'roaches
A few months ago a correspondent wrote from Madras of his experience
with the control of cockroaches using pellets of bait comprising flour and
sugar ‘spiced’ with boric powder (Letters, 1 August). While I have heard
of borax being recommended as a cockroach poison, it apparently acts slowly
and sodium fluoride is preferred.
However, I have personal – very favourable – experience with a slight
variation on this recipe for spicing the sugar-flour pellet. This is to
incorporate ordinary baking powder (sodium bicarbonate) into it. While humans
are fortunate to be able to expel an accumulation of C02 by burping, apparently
the digestive system of the cockroach does not permit of this luxury, and
their continued consumption of the baking powder leads to a state of gas
accumulation which causes the stomach lining of the cockroach to burst.
Exit cockroach.
The bait does not, however, affect dogs or cats or other domestic pets
as would their accidental consumption of most of the standard insecticides
recommended against cockroaches.
Whether the ‘explosive’ theory is correct I do not know, never having
the stomach to dissect the innards of the hoards of dead cockroaches observed
after their consumption of the bait. It was recommended to me as a ‘Buddist-insecticide’
(something contradictory about that combination of words!) the idea being
that you do not actually kill the cockroach, but that it kills itself through
greed. Perhaps an entomologist reader of New 杏吧原创 may like to comment
on the theory?
Ray Wijewardene Colombo Sri Lanka
Letters: Tyring tale
The challenge to readers to present ‘more ingenious methods of using
whole used tyres’ by Jonathan Horner (Letters, 24 October) is accepted.
I have for the last 15 years been experimenting with discarded rubber tyres
of cars, lorries and even tractors in gardening, landscaping and erosion
control with great success around my home and gardens of friends in Kuala
Lumpur, Malaysia.
I have used more than 1000 tyres in my experiments over the period stated
and there are more than 400 now around my house containing fruit trees,
ornamentals and vegetables, compost, sieved composted soil, subsoil and
so on, in a garden space of about 3000 square feet. Some of them are 15
years old in their undisturbed state and still serve the purpose as originally
intended.
Antony Santiago Kuala Lumpur, Malaysia
Letters: 120 per cent meat
With reference to your puzzlement about the labelling of meat products
(Feedback, 14 November), the answer is very simple. The labelling refers
to the notional raw meat content which has a significant water content.
If, in processing, this water content is reduced, the resulting product
can have an apparent meat content of over 100 per cent. A common example
is corned beef, which under the British Meat Products Regulations is required
to have ‘a meat content of not less than 120 per cent of the food and a
lean meat content of at least 96 per cent of the meat content of the food’.
A. Jobling Harpenden, Hertfordshire
Letters: Nice for N*k*
I am amazed at the number of news reports concerning a certain well-known
training shoe manufacturer’s foray into the world of oceanic currents investigation.
At the last count there have been 10 independent articles covering this
topic, including one between the covers of your own magazine (New 杏吧原创,
Science, 31 October) almost all with accompanying full-colour photographs
of said sporting footwear.
I am not without soul and you can call me a heel if you wish, but I
have ensured that I have not mentioned the company by name, lest they receive
even more publicity from this serendipitous event. Personally, I prefer
Re*b*ks.
David Bradley Cambridge
Letters: End of the spin
I missed John Chapman’s original letter (17 October) suggesting aircraft
wheels should be spun prior to landing, but I read A. J. Findlay’s reply
giving his reasons why they shouldn’t (Letters, 31 October).
I too used to think that it was surprising this was not done and had
visions of using air flow to spin the wheels prior to landing. This would
also have overcome most of A. J. Findlay’s objections. However, I discarded
my own ‘invention’ when I thought of something which should have been obvious
from the start: the gyroscope effect of spinning wheels would make control
of the aircraft more difficult and sluggish at the very instant the quickest
possible response was needed.
This correspondence is now closed – Ed
Richard Seligman Essendon, Victoria Australia
Letters: Mobile hole
Can your readers tell me what happens to an object with mass travelling
so close to the speed of light that its relativistic mass results in a gravitational
(Schwarzschild) radius which encompasses it? Would it appear as a ‘black
hole’ to objects that it approaches? Would the Universe ahead of someone
travelling on such an object appear as a kind of ‘black cone’, with only
objects travelling away from the object being detectable? Would fundamental
particles travelling with such energies be slowed down by collisions or
would they simply suck up other particles to increase their energy?
Could ‘Hawking’s radiation’ be detected from such objects since they
would be travelling so fast in relation to the virtual particles created
at their boundary? What would happen to time behind the event horizon of
such a ‘relativistic black hole’? Perhaps there’s a difference between inertial
and gravitational relativistic mass?
Jonathan West Exeter
Letters: Trolley trouble
I have observed shopping trolleys stranded at low water mark on the
sandbanks in the river Taw in Barnstaple. I assume that the trolleys are
voracious feeders and become enrapt in their activity so that they are overwhelmed
by the incoming tide. I suspect that the trolley population of Portsmouth,
by contrast has less need to feed on the mud banks in the nearby harbours,
for one rarely observes them there.
J. B. Bradbeer University of Portsmouth
Letters: Unique
‘Laying siege to ivory towers’ (31 October) purported to provide an
objective analysis of New Zealand science reforms as an input to the debate
on British science. Unfortunately, the article centred on the judgment that
an Australian research organisation has made of New Zealand’s science system.
This strikes me as particularly inappropriate.
The reforms of science in New Zealand reflect the structure of New Zealand
society, the nature of government in New Zealand, a suite of other government
policies and the likely future for this country. All these factors are unique
to New Zealand. Similarly, I imagine Britain will develop its science system
to best address its own, unique situation.
However, all nations can learn from discussing the principles, functions
and processes of their science systems with each other.
Simon Upton Minister of Research, Science and Technology Wellington,
New Zealand
Letters: Legalise fraud
Tired of swaying with the debate on the desirability of banning the
ivory trade, I believe I have come up with another way of saving our tusked
and horned friends from extinction.
The proposal is for those countries involved in the trade, be it legal
or illegal, to legalise the fraudulent sale of imitation ivory and ivory
products as the real thing.
This would have at least three effects: (a) the demand for real ivory
would diminish as demand was met by fake products, (b) legal employment
would be generated for people producing and developing ever better imitation
ivory and (c) a reduction in the market price would mean that those unfortunate
people clinging to the idea that ivory products enhance their virility would
get the same effect (zero or placebo) more cheaply or, eventually, disheartened
by the stories about imitations, give up the whole idea.
As a result of (a), the risks taken by poachers would become less well
rewarded, hence less tenable, and the threat to the endangered species would
surely be reduced.
Moreover, the governments would benefit by the introduction of further
sources of taxation comparable in nature, though far more moral, than those
on tobacco and alcohol. The idea would work better, however, if combined
with a ban, as this would hinder dissemination of information as to which
brands or sources were genuine and which fake.
This concept of legalising the passing off of imitation as genuine would
probably bear extension to other articles, the consumption of which is as
pointless as it is ecologically unsound. For example, the Japanese penchants
for bird’s nest and shark’s fin soups could easily be met by imitations
if the government would only allow manufacturers to use a false description
on designated goods.
Tony Hunt Rijswijk The Netherlands
Letters: Turtle truths
I feel that I must clear up F. G. Grisley’s questions concerning the
relocation of loggerhead turtle (Caretta caretta) eggs from existing rookeries
onto the ‘dozens of deserted, inaccessible beaches’ around the Greek islands
(Letters, 3 October).
The obvious answer would be that if turtles have not found these beaches
in their 150-million-year history, then they must not be suitable.
However, in a purely biological sense there are myriad reasons why relocation
would be dangerous, if not impossible.
The relocation of eggs is a very delicate operation which has to be
completed within 12 hours of oviposition. After this time period the eggs
begin a process of attaching the embryo to the egg wall; any rotation during
this critical period is fatal.
Eggs and their hatchlings have a chemical ‘imprint’ imposed upon them
by the beach itself during incubation. This allows successfully matured
females to return to nest on their birth beaches. Physical properties of
the sand itself are also vital to the success of nests. If sands are too
fine, or are deficient in calcareous materials, then eggs will die.
Even if nests could be successfully transported over long distances,
then upon hatching the turtles would find themselves in waters which lack
the circulation systems necessary to bring them to the feeding grounds essential
for reaching juvenile and adult stages of their life cycle. Indeed, if they
did mature then there would be little chance of a calculated return migration
by nesting females due to the lack of the same sea currents.
Unfortunately, Grisley’s questions are the same ones which landowners
and ‘beach entrepreneurs’ are now asking on Zakinthos. They simply try to
deflect the debate away from the real issues. Turtles have been swimming
the seas since dinosaurs were dominant. Now, due to human interference,
through fisheries and marine pollution as well as mass tourism, turtles
(and other large marine animals) probably face the most crucial period for
survival in their long history.
Surely it is us who should be thinking of relocation.
R. Weir Manchester
Letters: Doomsday dreams
A doomsday Swift-Tuttle comet arriving in 130 years (This Week, 24 October
and 14 November) and bodies more than 100 metres across once every 5000
years (‘How to destroy the doomsday asteroid’, 6 June)!
Before we accept that nuclear missiles can protect us from the doomsday
asteroid or comet, could we please consider the following points: If the
warhead impacts before initiation it won’t go critical.
If a nuclear explosion occurs a tenth of a second before impact it will
have no effect – it will be 3 kilometres away.
If it could be made to explode less than a hundredth of a second before
impact there would be no blast but the radiation would cause a comet (and
probably an asteroid) to explode. However, the centre of gravity of the
irradiated debris would still be travelling on exactly the same path towards
earth.
If a missile actually impacted without causing any division, the path
of the asteroid would be only minutely deflected – not enough to save us.
I suspect that the close explosion as above would be very difficult
to achieve. Both the timing and the aim would have to be perfect.
Not exactly a fail-safe situation . . . Are there any other ideas?
D. L. Giles Broadford, Victoria Australia
Letters: Sucking eggs
The Urban Aid Africa scheme to draw up building codes as a stimulus
to the wider adoption of house construction using red soil in sub-Saharan
Africa (Technology, 14 November) sounds like one of the half-baked (excuse
the pun) development schemes which we are taught to avoid assiduously.
African people have been building mud houses for a very long time and
I doubt that the shortage of ’10 million housing units’ can be ascribed
solely to a lack of building regulations.
By on-site trial and error African builders surely must have developed
more appropriate and flexible building styles than the one which Urban Aid
Africa will use with its imported Ghanaian soil in Newcastle (is that near
the Equator, then?). They already know how to reduce the impact of termite
damage – for example, they know which timbers are naturally resistant to
attack, etc.
With the Overseas Development Administration’s 拢100 000, Urban
Aid should visit Africa and find out from the locals what are the real factors
which determine how they build their homes. In some urban slum areas there
is little point in building permanent structures if you hold no title and
are likely to be evicted by the city commission next week and have your
house bulldozed.
People already know how to build houses. The question is: why are they
unable to build more? I am sure that the answer is not lack of information
on stress loadings and safety standards.
Simon Jennings Imperial College London
Letters: No easy answers
Graeme Coulam’s article on economics sketches a very misleading picture
of economics as a science (Forum, 7 November). Based solely on casual evidence,
he questions the scientific basis of economics.
Economists, however, know more about basic economic facts than they
receive credit for in Coulam’s article. Most economists knew, for example,
that in 1984 the dollar was overvalued, and for that matter the pound a
few months ago. What is essential here is that economics is not different
from other sciences: there are no easy answers to complex questions. 杏吧原创s
in the ‘hard sciences’ should not be too content with themselves. How many
different answers exist, for example, to the following questions: how old
is the universe, is the universe expanding or contracting, how many fundamental
particles exist, when is the next earthquake due, what causes AIDS or Alzheimer’s
disease?
One can add that to some extent economics as a science is burdened by
its predictability. Suppose the Treasury predicts a steep rise in inflation
for next year. It could be that because of this prediction trade unions
modify their wage demands and interest rates are increased (thus lowering
inflation). At the end of the year commentators might conclude that, once
again, economists were wrong, because inflation is not a problem at all.
Coulam may be right that a potential unifier in economics could be greed,
but try reading Adam Smith, who has nice things to say on this issue. His
Wealth of Nations is a good starting point for post-graduate research fellows
trying to learn economics.
Steven Brakman University of Groningen The Netherlands
Letters: Hungry for answers
We have been reading New 杏吧原创 for many years, although for various
reasons we have missed a few numbers. We have never seen anything explaining
three of our longstanding puzzles:
One, nearly all peasants that we have come across in our many travels,
including country people in France and England, believe that one should
plant seeds and cuttings when the moon is waxing; and some habitually get
their hair cut just after the full moon, believing that it will remain tidy
for longer. Having regard to the influence of the moon on tides (and in
our experience also on unstable people), this does not surprise us; but
has it been ‘scientifically’ validated and does modern agriculture allow
for it?
Two, how do spiders manage to suspend their webs across apparently unbridgeable
spaces?
Three, we are frequently warned that sedentary work uses little energy
and that intellectual workers should eat very sparingly; and yet we are
never so hungry as after several hours of intellectual ferment. Is it the
admonition that is wrong, or is it our stomachs?
Mr & Mrs I. D. Fraser Madeira, Portugal
Letters: Trolley trouble
Are your readers aware that shopping trolley and their sister species
luggage trolleys are protected under Section 99 of Part IV of the Environmental
Protection Act 1990? It is now an offence to abandon trolleys and we would
urge that the nation pulls together in affording them true environmental
protection.
Sam Martin Glasgow