Letters: Packing them in
James Levy asks if there are any theoretical limits to the growth of
the human population on Earth (Letters, 13 June). In 1964 JH Fremlin (‘How
many people can the world support?’, New 杏吧原创, 29 October 1964) showed
that there is an absolute limit to human population growth. This is the
number at which the heat produced by metabolism equals the amount of heat
that can be radiated off a sphere the size of the Earth – any increase and
the temperature will rise, since the Earth can no longer be cooled. He calculated
that this number was approximately 6×1016 individuals, or about 120 people
per square metre.
Of course, in order to reach this limit a number of technical problems
will have to be solved. This should be no problem, since the number of clever
people will increase exponentially as the population rises, and they should
have no trouble in solving these difficulties.
At the present rate of population growth, we should reach this ‘heat
limit’ in about 1000 years.
Peter Graham Radstock, Avon
Letters: Right to die
Your article on euthanasia in the Netherlands (‘The Dutch way of death’,
20 June) made much of the small percentage of cases (0.8 per cent of deaths)
where doctors assisted death without following the strict guidelines for
voluntary euthanasia.
These cases of ‘involuntary euthanasia’ are widely heralded by those
opposed to the right to die as proof of a slippery slope. It is crucial
to safeguard against abuse, but before condemning the whole idea of voluntary
euthanasia because of these cases, we should look more closely at what doctors
were doing when they shortened patients’ lives without following the formal
procedure. Most patients had previously expressed a wish for euthanasia
if suffering became unbearable; most were in extreme suffering and it was
too late to discuss medical decisions competently; in most cases life was
shortened by a few hours or days at the most.
Doctors who act to relieve suffering under these circumstances do so
out of compassion and a desire to fulfill their duty to help the patient.
This happens all round the world – not just in the Netherlands – and it
is nonsense to pretend otherwise. Indeed, since patients in this country
cannot escape any terminal agonies by opting for voluntary euthanasia, it
may well be that the incidence here is very much higher.
The Remmelink report also shows that doctors do not, and never will,
consider euthanasia lightly. Help in dying is the last resort and doctors
do not immediately accede to requests for euthanasia: some 9000 requests
a year were made by patients, but only 2700 cases of doctor-assisted voluntary
euthanasia took place.
There is truth in the adage that if you want the best from a Dutch doctor
you ask for euthanasia: that request will ensure that every possible alternative
avenue is thoroughly explored. But in the end, if the patient is still suffering
great pain or loss of dignity, 75 per cent of British people agree that
doctors should be able to give help to achieve a good death.
Since the Remmelink report showed that 54 per cent of all non-acute
deaths involved a medical decision, there is an urgent case for ensuring
that the patient is allowed a say at the end of life.
John Oliver The Voluntary Euthanasia Society (EXIT) London
Letters: Headache
This may seem a strange question from one who has been in electronics
all his working life, but what exactly is ‘charge’? Also, why do the electron
and the proton, apart from opposite polarity, have exactly the same quantity
of this thing called charge? No fatuous answers please! I have rubbed along
very well with my own version of the electron charge, but matching it with
three quarks in a nucleus gives me a headache.
The answer is: nobody knows – Ed
Martin McGrory Hemel Hempstead, Hertfordshire
Letters: Hedges and verges
I work in a large organisation that circulates its one copy of New 杏吧原创
to all who want to see it, so there is no surprise when it is months late.
Thus it is that on the same day I read both of Ariadne’s demise, and the
piece she wrote deploring the use of hedge trimmers (25 January). They are
a pet complaint of mine left over from my former rural life.
In the long term, flail hedge trimmers appear to cause deformation of
hedgerow shrubs regularly subjected to them. They become all top and little
bottom, providing a very poor barrier to stock and also being of little
effect as a windbreak or shelter. This depends both on the species of shrub
that is trimmed, and the time of year that the trimming takes place, but
in any event is far more damaging than the layering that was traditionally
practised. I have noted many stretches of hedgerow that are dying prematurely.
In addition to the trimming of hedges, and equally deplorable, is the
use of flails to trim roadside verges through the spring and summer months
by contractors engaged by local councils. This can be understood when verdant
growth threatens the safety of rural highways at corners, entrances and
junctions, and in all fairness some areas do only trim the inside of bends
and each side of junctions. But the widespread practice of trimming verges
over long, straight stretches of road during May and June can have no justification.
I have repeatedly written to local councils arguing against the waste of
money, loss of rural attraction, threat to local communities of flowering
plants and destruction of what can be a relatively safe and untouched habitat
in summer months.
Robin Lewando Langport, Somerset
Letters: First fax
If New 杏吧原创 of 27 March 1986 is to be believed, the original patent
for a fax machine was taken out in 1843 by Alexander Bain, a Scot (Technology).
The article tells us that the first practical fax was designed by Bell in
the US in 1925.
Lisa McGurk Stirling, Scotland
Letters: First fax
Your interesting account of ‘The world’s first fax machine’ (In Brief,
13 June) did not take note of the earlier and conceptually much more sophisticated
fax invented by F. C. Bakewell, who lived in Haverstock Terrace in Hampstead.
Bakewell described his ‘copying telegraph’ very clearly in his book, Electric
Science: Its History, Phenomena, and Applications, published in 1853. Not
only was this 13 years earlier than Caselli’s pantelegraph, but it solved
the synchronising problem without the need of independent accurate clocks.
Using tin foil and non-conducting ink for transmission, with Davy’s
electrochemical method of marking the paper, the six-inch -diameter transmitting
and receiving drums were rotated with falling weights and air fans, adjusted
so that, left to themselves, the receiving drum rotated slightly faster
– but they were not left to themselves. Synchronising pulses were transmitted
(12 per drum rotation) which actuated a solenoid for an intermittent brake
on the receiving drum. So this was an early feedback device. Bakewell also
describes the use of pendulums, which he preferred for single wire operation;
these also were synchronised with pulses, to a regulating magnet, and so
did not need to be extremely accurate clocks. Any error (especially when
setting the system up) was made visible by drawing automatically a vertical
reference strip which tilted if the drums rotated at different speeds.
The line scanning was done with a single fine screw thread, as in an
Edison cylinder phonograph (invented in 1877). So printing was by a continuous
line, about 10 rotations being needed to form a row of letters. Bakewell
claimed a normal writing speed of 300 words a minute. He could send confidential
handwritten messages using a chemical ‘invisible ink’.
Bakewell concludes that he had ‘received the assurance of some scientific
gentlemen who have been longest and the most successfully engaged in such
undertakings, that the copying of writing is the beau-ideal of telegraphic
communication, and that sooner or later it must supersede all other means
of corresponding by electric telegraph’. Not bad for 139 years ago.
Richard Gregory University of Bristol
Letters: Long lives
Charles Arthur states in ‘Design for the third age’ (13 June) that:
‘Until the beginning of this century the average life expectancy was 40;
designers could assume that their users were young.’ This helps to perpetuate
a widespread, careless use of ‘average (mean) life expectancy’.
The statistical mean life expectancy at birth is quite different from
a single individual’s chances of attaining old age. To quote from Aristotle
to Zoos: A Philosophical Dictionary of Biology by the late, great Peter
Medawar and Jean Medawar, ‘In demography . . . a certain fastidiousness
is called for in the use of technical terms . . . The mean expectancy of
life at birth, often used as a measure of the wellbeing and general medical
prowess of a population, has increased dramatically over the past few hundred
years. This is true mainly because of the diminution of mortality in infancy
and childhood . . . The mean expectation of life at later ages has not increased
nearly so much.’
Julia Kocich Astoria, New York
Letters: Right to die
One important aspect that was not discussed in either article was the
contribution of modern pain control treatments to alleviate pain, much support
for euthanasia being based on the desire to alleviate the pain of dying
people. Hospice doctors say that physical pain can now be controlled in
90 per cent of cases and significantly reduced in the remaining 10 per cent.
Making euthanasia legal is likely, at best, to reduce the funding for research
into more effective methods of pain control and, at worst, result in this
research being ended.
Mental anguish may also be experienced by a dying person and this can
be relieved by instilling hope. In Britain there are around 100 hospices
caring for the terminally ill and leading the way in both relieving pain
and instilling hope. It is perhaps worth noting that in the Netherlands
there is just one such hospice.
We quote Dame Cicely Saunders, founder of the hospice movement in Britain:
‘I’m against euthanasia for the positive reason of all I have seen people
achieve in the ending of their lives – times that they and their families
would have missed; and it’s often time after they might have asked to opt
out when they perhaps would have gone in bitterness, whereas they finally
go in peace and fulfillment . . . ‘
Richard and Hilary Okell Bristol
Letters: Packing them in
The whole world, land and sea, would be covered with tower blocks 2000
miles high, but life would not be unbearable because, on average, 1 000
000 Shakespeares and 4 000 000 Beatles would be alive at any given time.
John Brunner South Petherton, Somerset
Letters: Recycled roads
Tam Dalyell states that porous asphalt on roads reduces the noise but
requires frequent maintenance (Thistle Diary, 16 May). Have the Transport
and Road Research Laboratory not considered the idea of shredding discarded
tyres into crumb rubber and incorporating this rubber into the asphalt?
The scheme has been adopted in the US where 200 million tyres are generated
each year and 2.8 billion tyres discarded in dumps.
It is estimated that the cost is 20 per cent higher than normal resurfacing,
but the extended life of the road is increased by two to five times and
noise levels are reduced. Also, it solves the problem of tyre disposals
and would provide employment in a depressed area.
Jill Roberts Romsey, Hampshire
Letters: Unusual bus
The achievements of Mayor Jaime Lerner (Forum, 13 June) in recycling
and transport planning are evidently quite extraordinary. In recycling the
‘bus’ shown in the photographs, the Curitiba authorities have evidently
decided to add bogies with flanged wheels, couplings, a trolley pole, and
all the other attributes necessary to turn it into an even more environmentally
sound form of transport – an electric tram.
Perhaps this same technology could be profitably employed by some of
the British cities now busily replacing their buses with rail-based transport
. . . ?
Mark Hodson Rijswijk The Netherlands
Letters: Fair cop
I was dismayed to read in Feedback a brief item on the PoliceSpeak project
(6 June). Not only have you got your facts wrong (the linguistic experts
are from Wolfson College, Cambridge, not Oxford), you have committed the
additional sins of being both predictable and boring.
We have come to expect, from the lower end of the national press, inaccurate
and trivialised accounts of the project, resorting to predictable cliches
and sterotypes of the sub-‘Allo, Allo’ variety. It is particularly unfortunate
that a specialist magazine of your stature is capable of little more.
Without wishing to be seen as humourless, one need not be a scientist
or, indeed, a reader of your magazine to realise the importance of the
need to communicate unambiguously, particularly in an emergency where those
involved speak more than one language.
The PoliceSpeak team have broken much new and exciting ground; they
deserve more than to be patronised in your magazine.
P. A. Hermitage Assistant Chief Constable (Personnel) Kent County Constabulary,
Maidstone
Letters: Milk in tea
I don’t know about the taste, but I put the milk in last because it
enables me to titrate the tea to the right strength.
John Carpenter Mew Mills Derbyshire
Letters: Milk in tea
The answer is in British Standard 6008. This tells, in great detail,
how to make a cup of tea and, in clause 7.2.2, says that the tea should
be added ‘after the milk, in order to avoid scalding the milk’.
This BS is also an international standard. The real question is then:
Why can’t one get a decent cup of tea at an international standards meeting?
N. C. Friswell Horsham, West Sussex
Letters: Milk in tea
A strong preference for milk first or last derives from the human need
for consistent ritual. Most tea drinkers cannot taste any difference, but
believe they can rather than admit to being so primitive at heart.
Andy Prescott University of Leicester
Letters: Milk in tea
In my unfinished comic novel ‘Lampoon’, Sir Humphry Davy explains the
need to put milk in first:
‘If milk is added second, it is possible that greasy globules of milk
fat will float on the top, particularly if the milk is not entirely fresh.
Furthermore, the milk protein, casein, may denature, and not be able to
bind with the tannin, and modify the stringency of the brew.’
Colin Forrester Epsom, Surrey
Letters: Milk in tea
We offer the following explanation to Colin McCoy’s question about how
adding milk first or last affects the taste of tea (Letters, 20 June).
Strong black tea is a nasty brew which is rendered innocuous by the
addition of milk. The tea contains polyphenols which have a highly astringent
taste. When milk is added, the milk protein (casein) forms a complex with
some of the polyphenols which reduces the astringency.
When milk is added to a steaming mug of black tea, the temperature falls
to the equilibrium value. During this time, the milk gets hot enough to
denature some of the casein before it has formed a complex with the polyphenols.
On the other hand, if tea is poured onto the milk, the temperature
gradually rises to the equilibrium. The polyphenol-casein complex thus
has time to form before the milk protein is denatured, and remains stable
at this temperature.
Alison Ward and Stephen Beck Sheffield