Letters: Universal truths
Julian Brown (Review, 8 June) thinks a Theory of Everything will make
religious explanations redundant. Hogwash yourself, Julian! A Theory of
Everything has almost negligible explanatory power. Physics does not make
chemistry redundant, nor chemistry, biology. To the engineer, Ohm’s law
rules OK, despite quantum mechanics: to the quantum chemist, quarks are
irrelevant. High-level explanations are not deduced from low-level ones
but arrived at independently. Low-level explanations occasionally interact
with the high-level ones, but the thought that a Theory of Everything will
have anything to say about right or wrong, or why we are here, is utterly
implausible.
C. T. Sennett Malvern Worcestershire
Letters: Basking sharks
I welcome Leigh Dayton’s article on shark conservation (‘Save the sharks’,
15 June), but have to point out at least one error. Peter Gill, a biologist
with Greenpeace, was asked whether any of the world’s conservation organisations
have ever funded a shark campaign. His reply was no. Actually the answer
is yes, for at least one example – the basking shark in UK waters – has
been the subject of a campaign run by the Marine Conservation Society for
the last four years.
At present the joint nature conservancy councils are considering whether
the basking shark should be included on Schedule 5 of the Wildlife and Countryside
Act. The basking shark is in many ways equivalent to the cetaceans already
listed under the Act. With the cetaceans we have taken a precautionary approach
– action in the absence of adequate information, taken before the species
becomes endangered further and which provides a clear signal of concern.
It will be a great pity if future generations are deprived of seeing this
spectacular fish because of our lack of action and foresight.
R. Earll Marine Conservation Society Ross-on-Wye, Herefordshire
Letters: Moot point
Feedback (15 June) was mistaken to discriminate between American and
Japanese condom sizes. National standards in Japan (1985), the UK (1989)
and the US (1989), and the new International Condom Standard (1990), all
prescribe the same minimum length (160 mm). Whether this reflects universal
human erect penile dimensions remains moot, as published studies are conspicuously
lacking.
Most west European national standards prescribe testing for leakage
by measuring condom electrical resistance in a 1 per cent saline solution.
However, this technique is incompatible with British, Scandinavian and international
standards, which prescribe testing condoms for holes with 300 ml of water.
Fortunately, condom leakage is now comparatively rare, so this difference
of approach is not critical. The main source of failure is condom breakage;
yet Japanese, UK and US standards fail to prescribe condom total strength,
which causes inflation.
Concluding 15 years of debate (1975 – 90), the world’s first International
Condom Standard (ISO 4074) now prescribes air-testing for local weakness.
ISO 4074 minimum bursting pressure and volume exert a condom axial force
exceeding 20 newtons; that is, over seven times the force exerted by saline
or water-testing.
In 1989, both the Consumers’ Association and the Consumers Union (US)
reported a few condom brands which satisfied water-leakage requirements,
but failed ISO 4074 air-bursting requirements; thereby substantiating anecdotal
reports of excessive breakage in practice.
Unfortunately, pending the conclusion of a European Condom Standard,
the British Standard cannot adopt ISO 4074 air-bursting requirements. It
is earnestly to be hoped that the European Standard will soon prescribe
condom total strength.
Philip Kestelman London SE13
Letters: Castles in the sand
The article entitled ‘The self-organising sand pile’ (15 June) seems
to contain at least four implicit presumptions including dry sand, the grains
are of moderate size, the grains are rough and lumpy in shape and affected
by normal gravitational forces. In that form most engineers would agree
with an angle of passive or critical repose of 33 to 35 degrees. This represents
our angle of internal friction.
Larger lumpy particles such as rock rubble will have an angle of repose
of 40 to 45 degrees.
Very fine dry particles may have an angle of repose of 15 to 20 degrees
but with some it will be almost zero. Ball bearings would be likely to give
0 degrees, unless rusty.
If the particles are not lumpy but naturally rounded, as in piles of
dry grain such as wheat, the critical angle of repose will be more like
25 degrees.
Very fine, dry particles such as clays are affected by forces regarded
as cohesion and a friction angle is normally not attributed to them. Great
changes in criticality are also brought about by the presence of moisture,
free water, and water at excessive pore pressure.
The sand modelling described could be described as challenging but I
am not surprised that IBM found natural sands play dirty, because they very
often are dirty.
Noel Cochrane Crawley, West Sussex
Letters: Fuel's paradise
Further to John Brunner’s letter (8 June) and J. K. Jackson’s letter
(22 June), the question of what is meant by ‘fast growing’ is relevant to
the durability of the timber.
Some years ago, I was engaged in a study of trees suitable for fuel.
Many fast-growing trees produce large volumes of wood per unit area in a
short time but are out-produced in terms of the dry weight of timber by
what appear to be slower growing species. We found that both very light
woods and very heavy woods were inferior to medium weight timbers in terms
of the rapid production of mass.
In order to lock up carbon, it is desirable that the timber has utility
so that, when felled at maturity, the timber is not destroyed. The felled
area can then be replanted to lock up more carbon. Durability may or may
not be relevant depending on the use and whether the wood is protected from
the elements or not. The use of timber appears to me to be preferable to
the use of metal and plastics for desks and chairs, for example.
John Morris Horsham, Sussex
* * *
My answer to John Brunner (Letters, 8 June) would be ‘Raspberries’.
They provide the jam and mix well with an accomplice that spreads even
more easily – ground elder. But be warned. Ground elder goes on the rampage,
first horizontally and then vertically. However, they do allow self-propagation
by mountain ash, hawthorn and lilac.
My intention was to move the trees to hide an enormous shed and encourage
raspberries to amalgamate with wall/fence coverers (which they do quite
happily). After that I was going to expurgate the ground elder and put that
area out to grass (along with me). Now there is a temptation not to encourage
early retirement but to have a party for the green elder residents.
Chris Lesurf Fife
Letters: Insider dealing
I wonder if someone could explain something that has been puzzling me
for some time. We are told that if one gets enough matter in a sufficiently
small space it collapses to form a black hole from which nothing can escape.
We are also told that all the matter in the universe was created at the
same time at a single point. This seems, to me at any rate, like absolutely
A1 conditions for the formation of a magnificent black hole. How is it then
that the universe is flying apart?
Michael Jarman Bristol
John Gribbin writes: The universe may very well be a black hole – but
we are inside it.
Letters: Repel with a cause
One of our first year pupils asked, ‘Why do like charges repel?’
So, why do like charges repel, and how can it be explained to a first
year (and a chemistry teacher)?
Susanne Leitch Elizabeth Sargent Queen Anne High School Dunfermline,
Fife
Letters: Great shakes
At university there was usually one person who thought it was fun to
shake a beer can vigorously and replace it in the refrigerator. I was reminded
of this problem when my son (under 2 years old) did the same. Unfortunately,
there were two similar cans of beer. Can any of your readers think of a
way of telling the shaken from the unstirred?
Nick Beard London SW17
Letters: Sharp point
Right on, Jeremy Burgess! I, too, refuse to succumb (Forum, 8 June)
to guilt for those actions which are questionable at best. Still, one does
not have to bow to the weight of self-loathing in making decisions which
have benefits for others. For example, I have no doubt that my vegan diet
decreases the pain and suffering of the world; my certainty braces my shoulders
and lightens my heart, allowing me to feel more than a touch of pride to
offset the guilt of our species.
Donald J. Barnes National Anti-Vivisection Society Washington DC
Letters: The long and short
May I add a thought to Michael Kenward’s discussion of short-termism
in British companies (Forum, 15 June). He points out that pension funds
own a lion’s share of the equity in British business. Anyone expecting to
be paid such a pension might well wonder how short-termism secures the long-term
safety of the pension. How does it make sense to invest for the long term
in enterprises which may become seriously uncompetitive for lack of R&D?
If I was not already a pensioner, I would certainly be asking for an
R&D audit on my pension fund’s investments!
R. C. Dening Selsey, West Sussex Science on BBC
Letters: Science on BBC
I have just caught up with Glyn Jones’s Talking Point (1 June). He asks
when did anyone last see a science news item on BBC 1 or BBC 2.
He obviously does not watch the news, or he would have seen that in
April science-based stories on the BBC news included: reports on AIDS, the
space shuttle launch of the Gamma Ray Observatory, the diagnosis of child
sex abuse, the 13th anniversary of Yuri Gagarin’s first space flight, smoking,
the use of platinum-based anticancer drugs, the fifth anniversary of Chernobyl,
gene therapy, and a number of science-based environment stories by the environment
correspondent.
Most of May was taken up with preparing an edition of Public Eye, which
examined the treatment of asthma and which was broadcast on BBC 2 the day
before Mr Jones’s article appeared. The programme revealed that the Committee
on the Safety of Medicines has set up a working party on the use of beta-2
agonists to treat asthma – a ‘news’ story which New 杏吧原创 itself carried
a week later, though without crediting Public Eye as the source.
James Wilkinson, Science Correspondent BBC News and Current Affairs
London
Letters: Stoned age
I am surprised that Roger Lewin, in his article ‘Stone Age psychedelia’
(8 June), made no mention of the cult of ecstatic shamanism depicted in
the 3000-year-old rock paintings of the Pecos River area in Texas. Some
of the shamans are stylised human figures with deer heads, others are truly
psychedelic. Some have crow-like birds perched on their arms, reminiscent
of Carlos Casteneda and Don Juan. Others are surrounded by a fringe or aura
and shamanistic paraphernalia, including arm ribbons, both with and without
attached prickly pear pouches. These and other cultural artefacts have been
preserved in rock shelters in the desert environment. The drug of choice
for these shamans was the mescal bean, the bright red seed of the Sophora
secuniflora (Texas mountain laurel), which is common in the area.
Carol Hayman Austin, Texas.
Letters: Journey into space
I was disappointed to see your negative editorial on the subject of
the human exploration of Mars (Comment, 22 June). The debate on the relative
merits of human and robotic missions to the planets is an important one,
and it deserves more than the superficial treatment that you chose to give
it. Like you, I have little time for nationalistic arguments for space exploration,
but I would like to respond to two of your other criticisms. First you imply
that there is something wrong with the aerospace industry having a vested
interest in the proposal. It must be borne in mind, however, that the other
great vested interest of the aerospace industry is the making and selling
of high-technology weapons. It is highly desirable, for both social and
economic reasons, that these companies find something else to do, and an
ambitious space programme would be an excellent alternative. It is worth
noting that the estimated cost of the Mars mission, $500 billion spread
over several decades, is only half of what the world spends on weapons every
year.
Secondly, you imply that the educational argument for space exploration
is specious because the money could be spent directly on improving educational
facilities here on Earth. However, no one has ever suggested that space
should be funded at the expense of education, and it must be true that education
would benefit from any project that gets young (and old) minds excited about
scientific and technological issues. Schoolchildren are interested in space,
but those of us who visit schools to talk about it have to rely on slides
of the Apollo project in order to show human beings standing on another
world. Do we really want to teach today’s children that the high point of
space exploration was reached before they were born, and that they won’t
live to see anything comparable?
Ian Crawford University College London