Letters: Stormy debate
Paul Simons rightly argues that the continuing reductions in numbers
of weather ships reduce future ability to predict storms (‘Why global warming
could take Britain by storm’, 7 November). Accurate forecasts of storms
save lives and money. Unfortunately, Simons damages the case by using misleading
and inaccurate assertions to link his case to global warming.
He quotes the first report of the Intergovernmental Panel on Climate
Change (IPCC) in an attempt to substantiate an assertion that sea levels
are to rise. But the data on sea level used in that report were rapidly
superseded. The present scientific consensus is that global warming would
increase polar ice to reduce sea level.
Simons’s faith in the first IPCC report is selective. He claims there
are signs of more storms in recent years, but that report says, ‘There is
no evidence that climates have become more variable in recent decades.’
The IPCC’s 1992 report reaffirms this.
If global warming were to occur, then it is most likely that the frequency
and magnitude of storms would reduce. Severe weather is generated by temperature
differences. Predicted global warming would most increase polar temperatures
and thus reduce temperature differences. This is supported by the only climate
data cited in Simons’s article. He points out that frequency and severity
of storms increased in the lead up to the ‘Little Ice Age’ (as climate cooled).
The storms decreased after the ‘Little Ice Age’ (as climate warmed).
There is need for adequate numbers of weather ships, but there is still
no evidence of any kind for human-induced global warming. There is high
risk in this policy of placing all eggs in the global warming basket.
Richard Courtney Cheltenham, Gloucestershire
Letters: Galileo was wrong
It is ironic that Galileo has now been rehabilitated by the Pope (‘Vatican
admits Galileo was right’, 7 November) just when it is becoming clear that
Galileo was not entirely right and the old Catholic Church was not entirely
wrong. In a sense, the Earth is (as the Church insisted) at the centre of
the Universe, at least of the observable Universe.
The trouble was that neither Galileo nor his theological opponents could
imagine a Universe (‘creation’) without a fixed point. Galileo’s heresy
lay in declaring the Sun to be the fixed point and not the Earth. But as
Bertrand Russell pointed out many years ago, modern science has shown that
the Universe has no fixed point and all motion is relative.
This means that the Galilean controversy was largely beside the point,
so to speak. Whether the Earth orbits the Sun or the Sun orbits the Earth
is purely a matter of (changing) viewpoint. For everyday purposes, in everyday
language, we see the Sun as going round the Earth; if we are picturing the
solar system as a whole and calculating planetary orbits, it is much simpler
to think of the planets as moving round the central Sun. But, as Russell
stressed, the two viewpoints are not mutually exclusive; they are both ‘true’
– or, more correctly, both valid. This is a case where we can have the penny
and the bun.
Philip Lloyd Lewis Bournemouth, Hampshire
Letters: Willpower wins
I was surprised to read the suggestion that willpower is a relatively
unsuccessful method of giving up smoking (This Week, 31 October).
My own experience, and that of all of the reformed smokers I know, is
that will power is the key ingredient. Without the commitment to quit, none
of the other methods worked at all.
The conflict between my experience and the meta-analysis quoted in the
article leads me to ask how the study samples were chosen.
Studies which sample people on treatment programmes will always underestimate
the efficacy of willpower, since individuals who simply quit smoking, using
their unaided willpower, do not participate in treatment programmes.
Inviting people to participate in a trial is equally futile. Unless
someone has already made the commitment to quit, simply asking them to try
will not generate that commitment and the success rate will be low. More
fundamentally, we can’t anticipate the strength of an individual’s willpower
or commitment. We can’t establish that a person really meant to give up
until they have actually done so.
The best we can do is look at the general population; find those people
who have given up; and ask them how they did it. I suspect that if this
had been the only methodology used in the studies, willpower would have
a much higher success rate than quoted in the meta-analysis.
David Roberts Curtin, ACT Australia
Letters: Hoary frost
David Campbell (Survival in the crystal desert, 7 November) perpetuates
a hoary old fallacy in ascribing the lethal effect of freezing to disruption
of cells by ice crystals forming inside them. Most cells actually shrink
on freezing, because the ice forms outside them first, and then grows at
the expense of the water inside. Later, ice may form inside as well, but
the cells die anyway from dehydration.
If it is not too cold a solute can prevent ice forming by simply lowering
the freezing point, or more subtly, as he says, by smothering the points
at which ice can nucleate. The former way is how the antifreeze in your
car works, but it cannot prevent the radiator cracking if the temperature
gets low enough for the mixture to freeze.
This is where living cells have the advantage; with the right antifreeze
inside them they can freeze solid and still survive. This is because the
strong antifreeze solution remaining after all the ice has separated out
is able to dilute the cells’ salts to just below the lethal level. Only
the most harmless substances have any chance of working in this way, such
as glycol, glycerol, dimethyl sulphoxide and some amides. In nature we find
glycerol quite often, and also more exotic compounds such as dimethyl sulphonium
propionate. The larval midges which survive freezing probably contain some
such compound, not yet identified.
Tom Nash Sherborne, Dorset
Letters: Still expanding
I have already disproved (Scientometrics 20, 1991, 369-394; Nature 344,
1990, 806; 350, 1991, 370; 357, 1992, 272) 99 per cent of what Ben Martin
wrote in his claims of a British scientific decline (‘Struggling to keep
up appearances’, 7 November). He makes only one new claim. He states that
the world scientific literature is no longer expanding. As it has doubled
every 15 years since 1750 (Price D. de S, Little Science, Big Science, Columbia
University Press, NY, 1963) and as the numbers of scientists continue to
expand at about the same rate (Atkinson H. et al An Anatomy of Research
Personnel in UK Universities, SERC, 1992) this claim is violently improbable.
Terence Kealey University of Cambridge
Letters: Safe risk
The purposeful injection of plutonium-237 into consultant nuclear scientist
Eric Voice has been interpreted as a daring challenge to those who question
nuclear safety (Forum, 18 July). There are however several facts that Voice
failed to disclose to the reader.
Plutonium-237 is not an emitter of alpha particles (save for 1 in every
20,000 decaying atoms). It decays to nearly stable progeny, so there is
no chain of children with which to contend. Its emissions are garden variety
gamma and X rays, and conversion electrons, which are considered to be 20
times less hazardous per rad than alphas.
Couple all this to the minor quantity administered (20,000 becquerels)
and one calculates the dose to his liver or bone surfaces is about 20 millirems
from this exercise, equivalent to that from 10 or so weeks of natural background
radiation.
It is laudable that the metabolic data from this experiment will be
gleaned, and with such a low dose. But if Voice survives, I will not be
surprised; nor will he disprove the hazard of longer-lived plutonium-238
and 239 which are 10,000 times more hazardous than uranium 237 per unit
of activity.
Roland Finston Stanford University, California
Letters: Dengue danger
The problems of disposal of used car tyres (Letters, 24 October) needs
to be solved to prevent the international trade in used tyres spreading
the mosquito Aedes albo pictus, which hitches a lift in the stagnant water
that collects within them and in which it deposits its eggs.
This species is now a significant vector of dengue haemorrhagic fever,
previously only carried by Aedes aegypti, and has spread from the Pacific
and South East Asia to North America, Brazil, South Africa, Nigeria and
recently to Italy. Aedes aegypti has used the same means of transport to
reinfest all the countries from which it was once eradicated.
The role of used tyres in this spread was disclosed in September by
Norman Gratz, advisor to the WHO, in a paper to the 10th British Pest Control
Conference at Canterbury.
What is not explained is why anyone should wish to ship old tyres around
the world in the first place. Peter Bateman British Pest Control Association
Derby
Letters: Negative iron
Removing colloidal iron oxide from water (This Week, 31 October) is
easy, either by passing an electric current through the water to discharge
the particles or by adding electrolyte such as gypsum to a concentration
of about 5 x 10-4 moles and flocculating them.
The iron oxide is likely to have absorbed interesting substances such
as rare earths and may be worth extracting.
Guy Benians Hove, Sussex
Letters: No mystery
I read with interest the letter (7 November) regarding the alleged ‘Mystery
Spots’ which are supposedly found along the west coast of North America.
(There are others such as ‘Spook Hill’ in Florida).
Skeptical investigators such as magician Jerry Andrus and University
of Oregon psychologist Ray Hyman have long been interested in these spots
and have conclusively shown that they are nothing more than optical illusions.
The granddaddy of all such spots is the famous ‘House of Mystery at
the Oregon Vortex’ located in Gold Hill, Oregon. In August of this year
Andrus and Hyman recreated the vortex effect during a seminar sponsored
by the Committee for the Scientific Investigation of Claims of the Paranormal
(CSICOP) at the University of Oregon. It is quite a stunning effect that
can be easily recreated wherever one can find a sloping hill with trees
in the background. The trees serve to block off peoples’ knowledge of the
true horizon.
Several pictures of this ‘Vortex Effect’ will be published in the upcoming
Winter 1993 issue of the Skeptical Inquirer magazine.
Barry Karr CSICOP Buffalo, New York, US
Letters: Damn good soap
I read with interest Phyllida Brown’s article regarding malaria (‘Who
cares about malaria’, 31 October).
Last year I went on a motorcycling and camping holiday to the South
of France. It was in August and very warm, the first week that I was there
it amazed me that almost everyone else in the campsites was covered in mosquito
bites but I did not have a single one.
I put it down to the amount of beer and wine I was consuming, until
at the end of the first week I lost my bar of Wright’s Coal Tar Soap. A
day later I became a target for the mosquitos. I don’t know whether this
was coincidence and wonder if anyone else has had a similar experience.
Malcolm Jackson Chislehurst, Kent
Letters: Damn good soap
You describe a Chinese anti-malarial medicine artemisin as having been
known and used in China for the last two thousand years. The heading above
this states: ‘The drug that nobody knew about’.
Does your headline writer know something new about the mathematical
definition of zero, or is the description of the most populous national
on earth as ‘nobody’ a new form of prose licence?
Zula Nittim North Sydney, NSW Australia
Letters: Correction
Sally Croft, news editor of Physics World, has written to point out
some inaccuracies in the Careers article on science journalism in the 7
November issue. The Institute of Physics currently publishes or co-publishes
36 journals (not four as stated), around 60 books a year and two magazines,
one of which, Physics World, has replaced the Physics Bulletin mentioned
in the article.