Letters: Napoleon's trousers
I note Feedback’s attribution of Beachcomber’s Dr Strabismus etc. to
The Daily Telegraph and, by way of this communication, Express my disagreement.
M. Earwood Welwyn Garden City, Hertfordshire
Letters: Fission v fusion
Nuclear buffs shouldn’t quarrel amongst themselves, that’s for sure,
and I applaud Jeremy Webb’s enthusiasm for fusion (Technology, 22 January).
On the other hand, it does appear a little bizarre that such a long shot
is supported by governments at a time when they are busy extracting themselves
from commitments to the fast reactor – an already-developed technology just
waiting for an application.
There are imbalances wherever one looks. As far as thermal reactors
are concerned there is a virtual moratorium on their construction in Europe
and the Americas, with a corresponding reduction in research and development.
This contrasts with the East, where Japan, South Korea, China, India and
Pakistan will have operating, by the beginning of the next century, some
100 reactors, an increase of 43 per cent over present levels. Do the Eastern
entrepreneurs know something we don’t know?
The point about the fast reactor is that it can breed more fissile fuel
than it consumes. At a stroke, adoption of the fast reactor increases effective
uranium ore reserves by almost two orders of magnitude, and again by another
factor because it becomes economically viable to extract leaner ores. To
all this can be added the huge reserves of thorium ore, from which more
fissile material can be bred. It amounts to a supply of ore which could
provide all the world’s needs for at least a millennium.
The adoption of the fast reactor will then solve the energy crisis effectively
for all time, because, long before nuclear ores are exhausted, better energy
sources will surely be developed – including, perhaps, fusion.
Jack Harris Dursley, Gloucestershire
Letters: Matter of choice
Your correspondents (Letters, 22 January) are right to question Mark
Ridley’s rather hasty remarks about religion. But his main point is surely
true and very important. As he shows, it is an empty and misleading metaphor
to call religion, science, or any other human activity a ‘virus’ or ‘parasite’.
Since such concerns are just types of human activity – not exploitative
tapeworms with interests of their own – the central questions they raise
are all about human psychology, questions about why people choose to do
these things and how they turn out.
On those points there is often plenty of detailed evidence, including,
indeed, their effects on survival. But the telescope of population biology
is a much less helpful instrument for studying such matters than our existing
knowledge of motives. And tying mythical entities to that telescope is
a dangerous distraction.
‘Selection’ here is no metaphor. The people involved are literally choosing,
trying somehow to reconcile various values. Ridley’s dualist schema of a
rational and religious temper competing, like genes for blue and brown eyes,
absurdly distorts this complex process. But he is still dead right to slice
off, with Occam’s Razor, the useless and essentially superstitious notion
of ‘memes’ as independent, exploitative entities directing it.
Mary Midgley Newcastle-upon-Tyne
Letters: Porton Down
Many thousands of former Commonwealth servicemen, like myself, volunteered
for chemical weapons trials at Britain’s Chemical Warfare Establishment
at Porton Down.
Many years after the tests I became suddenly ill and on the suggestion
of my doctor tried to obtain my medical details from Britain’s Ministry
of Defence. It took a five-year battle for them to released, and then only
to my doctor under strict medical confidentiality. To date, I have still
not seen my own records.
I am now trying to set up an association of former servicemen who volunteered
for chemical or biological trials at Porton Down or other establishments
during the Second World War and over the last forty years. There have been
tests with mustard gas, nerve agents, CS gas and other gases, involving
patches on your skin or inhaling gas in a chamber; or tests with hallucinogenic-type
drugs. The aim of the association will be to compile a list of volunteers.
It would collectively represent the volunteers and apply for the personal
release of all medical records and information held by Porton Down about
the agents which were administered to us.
Where any ill effects can be properly established and proven we intend
to press the British government for long overdue acknowledgment, and for
pensions and compensation to be granted to service volunteers.
I can be contacted on 0706 868178 at anytime, or write to me at 14
Corporation Road, Rochdale, Lancashire OL11 4EU, enclosing a stamped addressed
envelope for full details of the Association.
T. Roche Rochdale, Lancashire
Letters: Laser safety
I was disappointed to read Barry Fox’s article (Technology, 15 January)
regarding the safety of virtual reality screens that use a laser system.
In fact, there has been a British standard for laser safety since 1972.
There has been close international agreement on the fundamental exposure
limits and a system of hazard classification since the International Electrotechnical
Commission published IEC825 in 1983. We have had a European safety standard
(BS EN 60825) since 1992. The latest, fully revised, version of IEC825 was
published last month and has been simultaneously adopted, with identical
wording, as a Euronorm.
If virtual reality screens reach the market without carrying a BS laser
classification, then there will be a need to give widespread publicity to
the above facts. Experience so far indicates that manufacturers of laser
products will meet the necessary standards, and it is premature to suggest
any reason for concern.
The detailed guidelines on calculating hazards from extended sources
(which these would be) have just been revised to take account of the latest
advances in scientific knowledge. If the devices use more than one laser
(to give colour rather than monochrome effect) then the guidelines cover
that, too.
Bryan Tozer Brockenhurst, Hampshire
Letters: Osmosis answers
Tom Harrison’s recollection of electro-osmosis being used to stabilise
quicksand to build wartime U-boat pens (Letters, 22 January) was, I believe,
in a paper based on work by Casagrande and quoted by me in articles on the
electro-osmotic damp proofing of British buildings. This technique was used
between 1962 and 1974 in over 55 000 houses.
In 1930, the Ernst brothers in Switzerland developed a system of applying
electro-osmosis to drying out foundation walls. Three Hungarians, Miklos
Lipscey, Imre Biczok and Zoltan Horvath, developed the system in Hungary,
Paul Wieden did so in Austria and Dinu Moraru in Yugoslavia, and it was
introduced in a patented system to Britain by W. J. Holmes of Rentokil.
The commercial use of electro-osmotic damp proofing of British buildings
was discontinued in favour of silicone injection.
Peter Bateman East Grinstead, Sussex
Letters: Osmosis answers
‘The application of electro-osmosis to practical problems in foundations
and earthworks’ by L. Casagrande was published as Building Research Technical
Paper No. 30 in 1947. Pages 7-9 relate to the U-boat pens at Trondheim.
Susanne Woodman Building Research Establishment Watford, Hertfordshire
Letters: Napoleon's trousers
I was interested to read about ‘Bracerot’, the nonlethal invention of
Dr Strabismus, whom God preserve, of Utrecht (Feedback, 22 January). I have
been told (but unfortunately have been unable to confirm as truth) that
one of the causes of Napoleon’s downfall in Russia was that prolonged exposure
to low temperatures caused an allotropic modification in the tin buttons
of his soldiers’ uniforms from the metallic form to the much more brittle
a form. The a form is the stable form below 13.2oC, but apparently the change
is very slow unless a temperature remains extremely low, as of course it
did that Russian winter. One can imagine the consequent problems, particularly
with fly-buttons.
C. Evans Earby, Lancashire
Letters: No mystery
Are people really still chasing the rainbow of ‘What is consciousness?’
(8 January)?
Rather than being the biggest mystery of all time, surely consciousness
is something we understand most intimately. Consciousness is the only thing
that we understand first hand; it is something we understand better than
anything else.
The real mystery arises when we try to understand and describe the outside
world in terms of our conscious feelings.
It is then that words are needed to describe and communicate our understanding
of the outside world, and that we are thus drawn into the ambiguities and
ineptness of language.
But don’t take my word for it.
Robin Pearce Southampton
Letters: Up periscope
I read with interest that periscopes may be used on future aircraft
making supersonic flights across the Atlantic (Technology, 22 January),
in order to overcome the problem of providing pilots with an adequate view
forwards and downwards.
I have to point out that this method has already been used on a transatlantic
aeroplane where the forward view was obstructed by additional fuel tanks.
The aircraft was Spirit of St Louis, the pilot was Charles Lindbergh, and
the date was 1927.
There is rarely anything new under the sun.
Patrick Abbott Bristol
Letters: Built of baryons?
Tom Shanks must be joking! (New 杏吧原创, Science, 22 January.) There
are several good reasons why the critical density of the Universe cannot
be accounted for by baryons alone.
Dynamics of galaxy clusters and rotation curves of individual galaxies
strongly suggest the existence of non-baryonic dark-matter.
Neutrinos, which exist in vast numbers throughout the Universe and which
probably have non-zero rest mass, should account for a sizeable fraction
of the overall density.
The actual distribution of galaxy clusters is best simulated in computer
models if the total fraction of critical density is definitely less than
‘1’ (that is, in the range 0.2 – 0.3).
If standard big-bang nuclear synthesis and estimates of primordial light-element
abundances are correct – and they are consistent with each other – the Hubble
constant would have to be very low indeed (less than about 20 km s-1 Mpc-1),
assuming baryonic matter provides 100 per cent of the critical density.
And, if H is not more than 20 km s-1 Mpc-1, the Hubble time is at least
48 billion years and the corresponding age of the Universe exceeds 30 billion
years. In which case a serious problem arises:
Why are there no stars older than about 16 to 18 billion years? (It
would be astonishing if stars did not form during the vast epoch between
18 billion and 30 billion years ago – especially in the relatively high
density phase of the first few billion years).
Moreover, interpretation of the Sunyaev-Zel’dovich effect – which forms
the basis for the recent lower estimates of the Hubble constant (30 to 40
kms-1 Mpc-1) – is still in its infancy. And, to make matters worse, these
particular values are based on the unlikely assumption that the observed
X-ray source (the hot gas permeating a galaxy cluster) is perfectly spherical.
In view of these considerations, it would be premature to ascribe special
significance to the new estimates.
Robert Nield Sir John Deane’s College Northwich, Cheshire