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In Canada, a bluenose is a person of Nova Scotia. I think the name refers to the traditional occupation of that province, fishing at sea under conditions that are so cold that one's nose turns blue. During the 1930s, there was a fishing schooner named The Bluenose, that worked out of Lunenburg, Novia Scotia. It …

In his article on traffic modelling, Philip Ball makes the highly dubious claim that reducing congestion will also reduce pollution (15 January, p 34) . Like many traffic engineers, he chooses to ignore the effects of induced traffic. Many decisions such as how to get to work or where to locate a business are based …

Tam Dalyell accuses the government of "pessimism" over its lack of support for solar electricity in Britain (22 January, p 49) . The main arguments against solar photovoltaics are well known: they cost a lot to install and do not produce much energy (well under 20 per cent efficiency), which yields very expensive power. An …

Your correspondent F. Gwynplaine MacIntyre suggests that the inertial "gravity" produced during space flight would be enough to overcome the problems associated with physical development in space (22 January, p 50) . But MacIntyre has obviously forgotten some elementary physics. The effect would only be produced during acceleration, which is unlikely to occur for the …

In the article on killing algae with clay spray it is stated that the clay sticks to itself (15 January, p 16) . This is in fact incorrect. The modified clay does not have the stickiness of the unmodified clay and therefore does not form a cap on the bottom of the river. A cap …

I wanted to pick up on the point made by reader Fred Grisley regarding the environmental consequences of biodegradable materials (22 January, p 50) . Any material derived from fossil fuels that ends up in our atmosphere as a gas is, generally speaking, bad news for the environment. Such products that remain as stable solids—as …

Could we not actively encourage the use of landfill sites for high-carbon wastes, such as much household refuse? Can the scientific community work out ways to stop groundwater contamination and the eventual return of the carbon to the atmosphere? If so, we could plant fast-growing trees with the intention of harvesting them for burial—effectively recreating …

Your correspondent Linda Shields is puzzled that a kidney was removed in an operation for an ovarian cyst (22 January, p 51) . Sadly, although the kidney is retroperitoneal and thus strictly outside the abdominal cavity, it can get in all sorts of difficult positions, and a gynaecologist may inadvertently remove a pelvic kidney thinking …

Henry Bortman describes work by Jordan Maclay on measuring and possibly extracting energy from the Casimir force (22 January, p 32) . The implication of the article is that it may be possible to extract vast quantities of useful energy from the zero-point energy of the vacuum. If a device exists that operates cyclically and …

So engineers have invented a friendly sleeping policeman for the slower motorist (8 January, p 7) . What I would like to see is a cycle-friendly hump. The designers of these fiendish things just do not realise that the abrupt changes of slope at the start and end of humps give a painful jolt to …

In suggesting that we should all have bar codes in our foreheads, your correspondent Brian Moss is millions of years too late (22 January, p 50) . Nature has already marked us with unique patterns of lines, on our fingertips and retinas amongst other places. Those on our fingers mark every manual transaction we make, …

The difficulty with Michael Hill's theory about the reason for Rudolph's red nose (29 January, p 52) is that it would be impossible to see Rudolph's nose when the Doppler effect is causing it to appear red, because you would only be able to see his rear end. I don't think the song would sound …

In the 22 January Feedback you say "According to the `Scole Report' in Proceedings of the Society for Psychical Research, no one was allowed to take an infrared or light-intensifying camera into the seance room, in case they harmed the spirits." I wonder what kind of harm might have been caused. Nothing life-threatening, I hope.