Dirty Old Masters
Your recent article on picture cleaning at the National Gallery (Forum, 3 June) seriously misleads your readers. Michael Daley argues that organic solvents commonly used to remove natural resin varnishes from Old Master paintings causes damage by extracting (leaching) “plastic components” of the paint films. He cites as evidence the weight loss experienced by test samples of oil paint when immersed in polar solvents. These experiments do not serve as a model for picture cleaning, and it is no surprise that 12-year-old and 400-year-old oil paint behaves differently in response to solvents.
Reliable evidence comes from the large number of analyses we have undertaken of real paint samples from paintings 鈥� of all periods and of all schools 鈥� in the Nationals Gallery’s collection. Particularly significant are the analytical results acquired using gas chromatography linked to mass spectrometry of areas of paintings where varnish has been removed mechanically, when compared with those where the varnish has been removed using solvents.
The results show that leaching of paint layers in easel paintings of any significant age during cleaning is the chimera most conservators have always known it to be. Instead, they quite properly concern themselves with the issues and practicalities of preserving paintings for the enjoyment of the public now and for future generations.
Naked truth?
Marcus Chown’s refreshing article on exaggerated claims of black hole discoveries, (“Obscure objects of desire”, 24 June) suggested three possible interpretations for the dark, massive objects in galactic nuclei: that they are black holes, that they are dim star clusters, or that they are exotic objects described by a nonrelativistic theory of gravity.
If these are indeed the only possibilities, it would be perfectly reasonable to conclude that black holes do exist. However, the possibility which was not mentioned is that the objects are naked ring singularities described by the naked Kerr solution to Einstein’s equations. At a theoretical level these rings are better understood than black holes, since a compete account exists of their topological development, whereas the interior topology of a black hole remains entirely mysterious.
Furthermore, there is evidence from galactic ejecta that collapse might be naked, and the critical measurement of angular momentum has yet to be made for any black hole candidate. The great mystery of black hole physics, for me, is how this straightforward possibility has remained hidden for so long.
Phoneyday
Only a few months after the nationwide renumbering of telephones that was to provide number space for the next decade, several cities are running out of numbers (This Week, 24 June). So Phoneday has turned into Phoneyday and certainly was “1 to remember”.
Why is central London not simply being allocated numbers with 0271 codes? The reason is simple 鈥� doing this would mean that to call your next-door neighbour you would have to dial all the digits, including the code, as if it were a national call. It would appear from Barry Fox’s report that Oftel is backing away from this and thus rendering the Phoneday changes useless in terms of increasing number space.
It is odd that since privatisation BT has wanted to change codes not telephone numbers. No doubt BT has all sorts of good reasons for changing the practice of previous decades, but I can’t help noticing one interesting spin-off of the change. Mercury (BT’s oldest competitor) uses in many of its customer’s premises a device called a SmartSocket. This automatically routes calls via the cheapest route and saves the customer having to remember to press their blue button before long-distance calls.
These devices work by storing known local codes and selecting routeing via Mercury only for those not in the list. Changing the end of the code would not have affected these boxes 鈥� for example, Reading calls would all still start 0734 even if the next digit changed. However, changing the start of the code so that Reading is 01734 invalidates the programming. Phoneday did this for every code in Britain 鈥� so Mercury had to replace every SmartSocket with a SmartSocket Plus programmed with the new codes. Very inconvenient for Mercury customers and expensive all round.
Knitted up
Further to Feedback (May 27) and Brian Dalton (Letters, 24 June) your readers might like to know that there is a review of the use of the knitted uterus, including details on where to get the pattern from, in the excellent Institute of Biology publication The Journal of Biological Education, vol 29, no 1.
Blinking silly
In your Patents page (24 June), you had a piece about an “eye-friendly” version of a laser weapon that would destroy the video sensors of enemy cameras and night-sights. It was proposed in Britain by DASA (Deutsche Aerospace). One can’t help wondering whether part of DASA’s recent financial problems were partly due to its employees’ innovative thinking and management’s lack of oversight. Applying for a patent is not cheap, more so when the idea seems of little merit.
There is a time lag before the human eye can react to a stimulus it receives. To notice the warning blue-green light sent at 530 nanometres and blink (protecting the eye from the high-powered laser), more than 0.1 seconds must elapse. But any half-decent, though not necessarily expensive, camera will have a shutter with a reaction time well under this. Coupled with a cheap light-sensor chip, the shutter can be made to close automatically if any light shines on it outside a band that the main optical or IR sensor is intended to detect. The 530-nanometre pulse would set off this shutter tripwire, protecting the camera from the subsequent high-powered laser.
If you flash light at a someone, they may well tend to look directly at the source, out of human curiosity if nothing else. Even if soldiers are trained to look away, what about civilians? So the DASA idea won’t destroy cameras, but could well injure humans.
This is an obvious case of a technological solution that was not fully thought through, and which ignores any operational considerations. It is an old maxim that it is not worth investing in something where the obvious countermeasure is both simple and cheap.
Stay off steroids
In your article on eye drops, you talk of “an antiglaucoma drug called dexamethasone” (Technology, 22 April). This is incorrect: dexamethasone is a test to detect the phenotypes in glaucoma families. It is well known and we were the first to publish in the 1950s that application of steroids such as dexamethasone can actually increase intraocular pressure in glaucoma patients.
I write this letter only to raise the standard of this otherwise excellent article.
Inflated facts
Feedback asks why American engineers would prefer to reprogram a car air bag’s accelerometer to ignore minor impacts occurring while the car is unoccupied, rather than interlock it with the ignition switch or with a seat weight sensor (17 June). The first alternative is illegal, since the car may be struck while parked but occupied. The second requires an extra sensor, and therefore costs more in the long run.
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E-chemistry
“Storming the barricades” by Robert Matthews (17 June) describes a future model attributed to Andrew Odlyzko in which the World Wide Web could be used as an alternative and more equitable system of peer review in science. However, fully functioning models along these lines are already in action. For example the ECTOC (Electronic Conference on Trends in Organic Chemistry) forum () has attracted wide global support and interest and many high-quality papers.
What was not mentioned was an even more important aspect of such a forum, namely the ways the Web can enhance quality and understanding. Thus ECTOC uniquely offers “built-in” molecular hyperglossary to which readers can contribute and which could serve to rapidly identify trends in a collection of articles, full keyword and molecule indexing, current access statistics, chem-mail in which molecular models can be enclosed with e-mail discussions, and hyperlinking to other articles and databases.
One paper even has the first example of the use of VRML, the virtual reality modelling language, to enable participants to explore for themselves complex 3D molecular wave functions.
Such scientific collaborations offer far more than the traditional printed journal can, and represent perhaps the best hope of increasing quality, perception and appreciation of what are traditionally regarded as difficult subjects. Britain is a world leader in such technologies, and the prospects look even better with the recently announced government funding for some 30 “e-lib” projects to promote innovation in information delivery 鈥� the FIGIT initiative.
Seafood culture
Some clarification of your editorial about whaling is needed (Comment, 3 June).
Firstly, as you say, Japan “quite freely” chose to stay in the International Whaling Commission; but the reason for staying in is not what you suggest. Japan’s reason is to uphold the purpose of the IWC charter “to provide for the proper conservation of whale stocks and thus make possible the orderly development of the whaling industry”, a duty for a member nation.
In spite of this purpose, the IWC has kept the moratorium over the time limit after the completion of necessary comprehensive assessment, and established the sanctuary covering all whales, regardless of population sizes of different stocks estimated by the IWC’s own scientific committee. Such decisions are a blatant departure from the spirit of the charter. Would you say that the proponents of the sanctuary are also “quite free to be members”?
Japan’s food culture is markedly dependent on seafoods. Whalemeat is one component of this culture. Just as cattle and sheep cultures are accepted in some parts of the world, seafood culture, including whalemeat, should also be recognised.
Indeed, the welcome address by Michael Higgins, Ireland’s minister for arts and culture, at the IWC Annual Meeting in Dublin in May-June this year, supports this. He said: “I believe it would be wrong and in the nature of cultural imperialism for Ireland to attempt to impose our cultural values on those nations whose populations have developed on the whale for generations.”
Future generations will face food shortages associated with growing human populations. The future global population will require greater protein supply than ever before; this can hardly be provided by production from the land alone.
The proper management of ocean resources, including whales, must be practised to keep the balance of the marine ecosystem. Cetaceans, at the top of the food chain, consume massive amounts of other marine creatures 鈥� between 3 and 5 per cent of their body weight per day during the feeding season. Whales all over the world consume at least 300 million tons of krill and other species, exceeding four times the amount of fish caught by humans worldwide.
Harnessing oil rigs
Wind power is the way forward to renewable and sustainable energy into the 21st century. However, land-based wind farms are noisy and unsightly, and produce fluctuating power according to local conditions. A sea-based wind farm would produce continuous electricity without spoiling the views for people on land. It would, in effect, be no more obtrusive than the existing oil platforms which could support it.
The challenge, I suggest, is to convert defunct oil installations into active electricity generating units (“Breaking up is hard to do,” 24 June). There are technical considerations to be accommodated, not the least of which is how to get the electricity to land where it can be used. The obvious solution is to use existing oil pipelines to carry electricity cables to the shore. In situations where this may not be practical it will be possible to use a novel strategy: seawater electrolysis.
Electrolysis of seawater would convert wind energy, via electrical energy, into chemical energy. The products of this process are hydrogen gas and chlorine gas. Both these gases are invaluable to the chemicals and allied industries. Both can be compressed and bottled for storage and transport. They can also be utilised to recreate electricity.
One fundamental point grabs me about this idea. After the initial installation the raw materials cost nothing, and there are no by-products of this process. The beauty of this scheme to companies like Shell is also one of publicity. Imagine how Shell’s critics would be silenced when told that it was recycling its old oil platforms into modern, efficient, environmentally friendly electricity and/or chemical generating plants.
Cash for space
So Dan Goldin thinks he has a case when he pleads for more money? In a brilliant appraisal of NASA’s current financial dilemma (“The rocket man”, 24 June), Arlan Andrews got more than he needed to make it clear that NASA needs to be slimmed down. Interviewed by Andrews, Goldin claimed: “The Apollo programme took about 5 per cent of the federal budget in its time. Today’s equivalent of that would be around $80 billion per year.”
In the 12 years over which it was funded, Apollo took less than 1.1 per cent of the federal budget, although in the peak year (1966) funding for the Apollo budget soared to 2.2 per cent. Perhaps Goldin meant the whole space programme took 5 per cent and not just Apollo. Over the same 12-year period (1961-1972), excluding the fraction spent on aviation, NASA received 2.58 per cent of total government expenditure.
Today’s equivalent of the 1966 budget is $20 billion based on Apollo alone, or $24 billion for the whole NASA space programme in that year. If NASA received 2.58 per cent of today’s federal expenditure, the proportion received during the Apollo era, its budget would be $41 billion 鈥� not $80 billion.
More to the point, NASA’s money has shown healthy growth in real terms, going from the 1981 budget of $8.8 billion in 1995 prices to almost $15 billion today. In the same period, at 1995 prices, NASA spent almost $20 billion on paper studies for a space station it has redesigned six times.
Come on Dan, stop the bleating. Violins and heart strings may make good music, but they will never win an argument against facts. No wonder NASA has such problems getting its project estimates correct and its hardware off the ground.