Letters: Time's arrows
I am writing in response to Gareth Rees’s article, ‘The longbow’s deadly
secrets’ (5 June). A minor point concerns the length attributed to the
medieval arrow. Rees gives this as being ‘typically’ 71 to 76 centimetres
long. However, I believe from my research that a large majority of the
arrows were 90 centimetres in length, which would presumably add a
significant amount of mass to the arrow, thereby necessitating a
recalculation of the arrow’s performance.
The article also states that ‘. . . an arrow must be ‘tuned’ to its bow’,
giving the impression that each individual bow was accompanied by its own
special set of arrows. This is untrue. Arrows were made of almost any wood
that was flexible enough to suit almost any bow. They were carried in carts
whilst the army was on the move. During battle, archers were replenished
with arrows by children, who fulfilled a similar role to the ‘powder
monkeys’ of later navies.
Rees also states that there is some debate as to what the exact draw weight
of the medieval bow was. This is difficult to establish, but it is rash to
claim that: ‘. . . there seems no reason to believe that the bows used in
Henry VIII’s day, when English archery was already in decline, would have
been significantly more powerful than 130 years earlier, when archery was at
its peak’. Firstly, Henry VIII’s bowmen were a picked, specialised body of
men, and their equipment was likely to be superior to run-of-the-mill
military hardware. Secondly, with the increased threat to the longbow posed
by firearms, it is likely that the longbow would be improved to extend its
usefulness.
Finally, Rees states that the longbow was made of yew. Certainly some bows
were made of (particularly Spanish) yew. But this material was both rare and
expensive. Consequently, a large majority of English longbows employed
throughout the Hundred Years’ War were fashioned from elm. The inferior
properties of this material were offset by its plentifulness and I would
maintain that a far more accurate impression of the overall performance of
the medieval longbow would be gained if attention was directed towards the
elm longbow.
Calvin Hedley
Coventry
Letters: Tinkles and taps
I have read with interest your comments in recent months on the telephone
tinkling phenomenon (Technology, 20 March). I have some further
information.
The British telephone network now supports the Integrated Services Digital
Network (ISDN) protocol. This allows digital devices (such as fax) to share
the system with existing telephones. The ISDN subset that BT implements is
defined in their document BTNR 191, ‘Signalling CCITT I-series interface for
ISDN access’.
On modern tone-dialling phones, the ‘ringing’ is controlled by the local
controller chip rather than a high-voltage ringing signal from the exchange.
The network indicates the arrival of a call to your phone by sending a setup
message. This is the start of an electronic conversation between your phone,
fax or modem and the exchange, and is how BT can check your line without the
phone ringing (hopefully).
Built into the international CCITT protocol is the ability to take the phone
‘off the hook’ and listen into conversations occurring near to the phone
without the user being aware this is happening. BT states that this is not
implemented in the British system, but then they also deny that all our
transatlantic calls are monitored by the US security services at Menwith
Hill. It is difficult to find the truth in areas considered to be of
national security.
In the meantime, if you want to keep your secrets safe – remember that
someone may be listening to your every move. This includes phones connected
to office switchboards and is even a publicised feature on some.
Alasdair Philips
Ely, Cambridgeshire
Letters: Juicy mistake
Re ‘Applejuicegate’ (Thistle Diary, 12 June). Had the junior minister
Nicholas Soames followed his own advice when stating, ‘we do not do anything
unless the advice is both scientific and substantiated’, he would not have
then gone on to say, ‘we should not forget that apple juice is a useful
source of Vitamin C’, since there is virtually no vitamin C in apple juice.
Kay Bagon
Radlett, Hertforshire
Letters: World's greatest
The main reason for the current pattern of low-density development and high
car use in Los Angeles is, quite simply, the astronomical subsidy to road
building. Gasoline taxes are very low, and private transport is subsidised
by local, state, federal and private authority money and planning policies.
Public transport cannot hope to compete without a similar subsidy in terms
of money and preferential access to road space. When money is provided for
schemes such as the Blue Line, then public transport use increases, as I
saw for myself on a journey from LA to Long Beach on a well-loaded light
railcar.
Contrary to popular assumption, the LA Metro project (road building, public
transport and all) will not relieve traffic congestion.
In any wealthy urban area, private road traffic simply expands to fill any
space provided for it; there is always a suppressed demand for more road
space.
Better public transport attracts some car drivers, but the vacated road
space immediately fills with newly-generated traffic. Road congestion can
only be cured by politically unpopular road pricing or physical restraint,
coupled with investment in public transport, cycling, walking and land-use
planning to minimise the need to travel.
R. M. Goodall
Newark, Nottinghamshire
Letters: World's greatest
It is unfortunate that Dan Thisdell’s stimulating description of the impact
of recent urban railway developments in Los Angeles (‘Can LA kick the car
habit’, 12 June) begins with the erroneous statement that the city ‘has
never had an underground railway and public transport of any kind has always
been a rarity’. In fact, during much of the first half of this century, the
Los Angeles area enjoyed not only what was claimed to be ‘the world’s
greatest electric railway system’, the 1000-mile standard-gauge Pacific
Electric network with up to 2700 scheduled trains daily, but also its own
extensive 1067-millimetre-gauge, urban streetcar network. Indeed, the city
largely owes its original rapid growth to these networks.
Furthermore, between 1925 and 1955 the PE cars ran underground for 1
kilometre to reach the downtown terminal at Hill and 5th Streets; the
northern portal of this disused tunnel can still be seen today, near the end
of Glendale Boulevard.
Alan Reekie
Brussels, Belgium
Letters: Private rhinos
I hope Mary Cole’s concern that personnel changes at the National Parks
department in Zimbabwe may bring about policy changes which could be a
threat to the private black rhino conservancies (This Week, 12 June) is
unfounded.
The three main rhino conservancies in Zimbabwe are established on private
farm land in the Midlands, and at Bubiana and Save Valley in the Lowlands.
They each have a viable breeding population of about 40 dehorned free-range
black rhinos where they can be protected against the poachers.
The private conservancies are a vital part of the official Rhino Strategy of
the Department of National Parks and Wildlife Management and from my meeting
last week with the Director, Willie Nduku, I can vouch that they still have
his full support.
During the last three years there has been a dramatic drop in the population
of black rhinos in Zimbabwe from 2000 to 350 due to the continued killing of
the rhinos by the poachers for their horn.
Armed anti-poaching units under Operation Stronghold have not been able to
provide adequate security for the rhinos in large areas such as the Lower
Zambezi Valley on the Zambian border.
Experience in Kenya has shown that the most effective strategy for rhino
conservation is to protect small populations in situ in sanctuaries or
conservancies.
John Gripper
Sebakwe Black Rhino Trust
Ascott under Wychwood, Oxfordshire
Letters: Time's arrows
How long did the battle at Agincourt last? With the statistics given and the
archers firing at 50 per cent of their capable rate they would use in excess
of 80 tonnes of arrows per hour. Did they carry these all the way from
England?
If so, to sustain Henry’s campaign they would have required at least 50 to
100 kilograms of arrows per archer. If not he required another army to
manufacture the arrows on site.
Brian Ashley
Hillingdon, Middlesex
* * *
Gareth Rees writes: It is unlikely that Henry V would have taken more than
about half a million arrows (perhaps 50 tonnes including the barrels in
which they would have been packed) on his 1415 campaign, enough for only
about 10 minutes continuous shooting at the maximum rate by his 500 archers.
Most of the three-hour battle would have involved hand-to-hand combat, with
only the earliest phase being dominated by brief, intense and one-sided
archery.
Letters: Time's arrows
I doubt that even a glancing blow would have offered the enemy much chance
of escape. It was the practice of the archers to place a bead of beeswax on
the point of the armour-piercing bodkin arrow head. The effect was to check
the progress of the arrow, momentarily, allowing the shaft to assume a more
square attitude to the surface of the armour before the bodkin point hit;
this allowed a much better opportunity for effective penetration.
This was demonstrated some years ago by the actor Robert Hardy, also a
toxophilite aud longbowman of some renown, in a television programme hosted
by Jack Hargreaves. Hardy loosed a modern broadhead arrow at a Second World
War steel helmet from a distance of about 30 metres. It glanced off. He
then added a bead of beeswax and tried again. This time the arrow pierced
the metal leaving a rut of about 3 centimetres long before rebounding. Had
he used a bodkin point it would certainly have passed through the helmet.
This technique of the medieval archer has a parallel in more recent times.
Many years ago I was shown a Second World War armour-piercing bullet. It
comprised a tungsten core in an aluminium jacket. The aluminium momentarily
checked the bullet, allowing it to assume a more square attitude to the
surface of the armour before the tungsten core hit and penetrated the
armour. Sadly, some things never change in this world.
Alan Forster
Nottingham
Letters: Time's arrows
The yew longbow was not round in section but D-shaped and was in fact a
composite bow. The outer flat face was formed from the thin layer of sapwood
and the inner side from the heartwood.
B. Robinson
Newcastle-upon-Tyne
Letters: Time's arrows
Rees states that ‘the English led the rest of the world’ with the longbow. I
believe, though I don’t know where to find the evidence, that the invention
was Welsh.
Eric Franklin
Pirton, Hertfordshire
Letters: On the spot
Re ‘Iraq caught out over nerve gas attack’ (This Week, 1 May): The Chemical
and Biological Defence Establishment at Porton Down, Wiltshire, where the
latest samples were analysed says: ‘This is the first time, to our
knowledge, that a suspected use of nerve agent has been corroborated by the
analysis of environmental residues’.
I completely disagree. Since 1984, my colleagues and I have analysed
environmental samples and human autopsy material that we took ourselves at
the battlefields of Cambodia, the Iran-Iraq war and Angola.
More than one thousand Iranian villages were bombed with war gases by Iraq.
Nobody from the Western world wants to speak about it. The same is true for
mothers and children chemically bombed by Luanda (Angola) in UNITA-held
territory. Where are the results of these samples that Porton Down received?
We do the analysis in two hours. Why does it take months for Porton Down?
We were at Halabja a few days after the bombing, took samples and analysed
them. Videos and reports are available. The UN was not there. Iraq was
never condemned by the UN for using chemical and biological warfare against
Iran. It is only after Kuwait that people now speak about it.
Thanks for confirming our results.
A. Heyndrickx
Ghent, Belgium
Letters: Keeping in style
Apart from mirror handwriting (Letters, 22 May and 12 June), there is
another curiosity.
Writing at a table, the arm rests, and most movement of the hand uses the
wrist.
Writing on a blackboard, the whole arm is used, which brings the elbows and
shoulder into play.
Why is it that such different movements produce identical handwriting?
F. G. Grisley
Barry, Glamorgan
Letters: Godalming effect
On Godalming station on British Rail’s Network SouthEast there is a digital
clock. It has four faces. Each face has six numbers each made up of seven
electro-mechanical segments. The faces clank away at a 24-hour reading of
hours, minutes and seconds in perfect synchronism. Except that, for more
than two years now, on one of the faces, one of the numbers – the one giving
the minutes units – has insisted on displaying an ‘8’ whenever those on the
other three faces show a ‘0’. In every other respect the clock behaves
itself. The station staff insist that the maintenance engineers have been
unable to locate any fault. Got all that? Here come the questions.
Does Godalming station sit on a warped bit of the space-time continuum?
Is it safe to travel on a railway that can’t get the clocks to run on time?
Rupert Gareboie
Godalming, Surrey
Letters: Poplar power
I was very interested in the description of a greenhouse (Technology, 29
May) designed to condense moisture out of the air blowing over it and grow
vegetables inside it.
There is a tall poplar near us which I have often noticed performs a trick
somewhat like this, in that on moist humid days when the air is saturated
with moisture but just too warm to condense as ‘Scotch mist’, and a
noticeable wind is blowing through the foliage, the tree condenses out quite
a good supply of water which drips through the leaves and ends up in a rough
circle somewhat wider than the diameter of the tree.
Poplars of course have leaves which dance and flick about in a breeze, and I
imagine it is this flickering motion which helps the tree to ‘comb’ water
out of the air blowing past.
We round here (West Gloucestershire, almost at sea level) do not get this
sort of weather very often. But in Lanzarote or the coast of Namibia such
conditions are common. In such a climate a row of poplars might comb out
quite large quantities of fresh water, far more than the tree would need to
maintain itself.
Alec Vans
Newnham, Gloucestershire
Letters: Potato power
Re Maxwell Woosnam’s idea of getting electricity from genetically
engineered trees (Letters, 29 May). I purchased a ‘potato clock’ recently.
This is a device which uses a potato (or other acid-based item) to power a
small digital clock via two wires embedded in the power source to complete
the circuit.
Although my understanding of science is minimal, I would presume that a
bigger source (such as a pine tree) or more of them would provide a larger
amount of electricity. Given a big enough or wide enough input from the
source (such as a field of potatoes or forest of trees) it must be possible
to power something like a home’s electricity needs. I don’t know if any
experiments have been conducted to establish the electrical output of trees,
but perhaps other readers would care to comment on this idea.
David Fulford-Brown
Coventry
Letters: Heavy water
Andy Coghlan (Forum, 5 June) must have some difficulty making coffee at home
if he can dissolve 1 gram of coffee in a kettleful of water and achieve a
concentration of 1 milligram of coffee per litre of water. When full, his
kettle must weigh around 1 tonne and would be hard to lift onto the stove.
It should also be noted that 1 milligram per litre is, in fact, 1 part per
million and not, as stated, one part per thousand.
To get a rough idea of what 1 part per billion represents, imagine a
teaspoon of sugar dissolved in an Olympic swimming pool.
John Vine
Doncaster, Australia
Letters: New is old
One can only cringe at Julian Rose’s review of Victor Anderson’s Energy
Efficiency Policies (12 June). If either Rose or, worse, Anderson, really
believe that environmental taxes, of which a carbon tax is but one
instance, constitute a ‘new economics’ they are guilty of gross
misrepresentation and neglect of economics as a discipline.
The idea of correcting environmental problems through price measures has
long been part of orthodox economics. I wrote an undergraduate textbook on
the subject in the 1970s when it was already commonplace to teach such
ideas, the origins of which go back at least to Arthur Pigou’s Economics of
Welfare first published in 1920. Julian Rose’s review also reveals
ignorance: carbon taxes actually exist in several countries, and no UN body
(one imagines Rose is referring to the Intergovernmental Panel on Climate
Change) has ever recommended a 60 per cent cut in greenhouse gas emissions.
Shouldn’t ‘new economists’ find out what old economics says first? And
shouldn’t ‘science writers’ stick to science?
David Pearce
CSERGE
University College London
Letters: Too much light
Concerning the debate about the surprising lack of black plants (Letters, 15
May and 5 June). Many of your correspondents have agreed with the
assumption that light is often the limiting factor in plant growth, but
none has pointed out that it is sometimes too much light, rather than a
lack of it, which inhibits growth.
Photoinhibition is a serious problem for farmers who wish to grow crops in
areas of the world which receive rather more sunshine than we enjoy. The
exact cause of this effect is not, as far as I am aware, fully understood,
but it is suspected that plants are damaged by too much light through the
action of reactive oxygen species including superoxide, peroxide and
hydroxyly radicals. Sigma, but more likely Delta singlet oxygen species have
also been implicated.
These reactive species are associated with the electron transport apparatus
within the chloroplast. Their production might be expected to rise, with
damaging effects, in much the same way as they do for humans suffering from
porphyrin-associated metabolic disorders (porphyria) where the skin is
sensitised to light.
Black plants, absorbing most, or all of the light spectrum, might be open to
this kind of inhibition at even relatively low levels of light. I am not at
all surprised that nature has chosen to be a little more selective.
Paul Leonard
London
Letters: Forever corrupted
There is no logic to the request by the British Phonographic Industry for
discount on royalties when sound recordings are published on the new digital
formats, the Digital Compact Cassette and the Mini Disc (This Week, 22
May). However, only a week later (Technology, 29 May) the reasoning is
there, plain for all to see: Barry Fox reports that Matsushita has
demonstrated that both systems ‘omit sonic content’. So it’s only natural
that you don’t pay full royalties when you don’t sell the full sound.
Precisely this property of the so-called data-reduced formats makes sound
archives worldwide very concerned indeed. All utilisation which is not mere
listening will be forever corrupted, because the statistics of the sounds
have been irretrievable altered.
George Brock-Nannestad
Nyborg, Denmark
Letters: No monopoles
In reply to Pat Delgado’s letter (29 May) concerning ‘magnetic monopoles’, I have a number of points to make. Firstly, the devices he describes are not true monopoles as they have no net magnetic charge. Any student of Maxwellian electrodynamics would be able to deduce that the net magnetic flux through a closed surface surrounding any such device is zero.
In particular, a spherical device such as the one described at the end of Delgado’s letter would produce no external magnetic field, if genuinely spherically symmetric.
A diagram of some magnetic field lines should help to clarify the situation.
Liam Roche Watford, Hertfordshire