Letters archive

Rats have been taught the complex skill of driving a tiny car to collect a food reward at their destination, Alice Klein tells us ( 2 November, p 12 ). Monitoring the rats' levels of hormones associated with stress showed that they were relaxed: online you report that they were less stressed than rats that …

Brendan Foster describes renewed interest in the luminiferous aether ( 2 November, p 32 ). For all its shortcomings, the aether was one of the most productive scientific ideas of all time. Many conceived of it as being electromagnetic as well: it allowed James Clerk Maxwell to deduce that light was an electromagnetic phenomenon. The …

Reading Helen Thomson's interesting and amusing article on hypnosis, I wondered if hypnotists aren't taken seriously because, historically, they claimed to be using only their minds to do it ( 9 November, p 34 ). As Thomson reports, anaesthetist Aurore Marcou uses local anaesthetics and mild sedation in modern, medical-based hypnosis, making the hypnotist one …

Debora MacKenzie reports that measles massively damages the immune system ( 9 November, p 15 ). In 1960, before vaccination was available, I had two weeks off school with measles. On the first day back, I came home covered in chickenpox. For decades I have suspected that there was some relationship. Thanks to New Scientist …

With Clare Wilson's article on the neglected nutrient choline, you present a diagram showing beef liver as an important source of it ( 26 October, p 20 ). As Wilson reports, some research suggests that women should have more choline when they are pregnant. But pregnant women are advised to avoid liver of any kind, …

Reviewing the Moving to Mars exhibition, Simon Ings offers some welcome balance to dreams of long-term space exploration ( 26 October, p 30 ). I would add some ethical issues. Adventurous adults may make informed, rational decisions about leaving Earth permanently. But if this isn't to be temporary, there must be plans for them to …

You mention the camera obscura as an example of unconventional imaging ( 9 November, p 42 ). I saw a camera obscura after moving into a house with high ceilings, tall windows and a short front garden. On a bright first morning, I saw tiny figures moving on the ceiling. The folds at the top …

As Adam Vaughan says, gas boilers are a UK election battleground, with three of the main parties wanting to phase them out, each at a different rate ( 9 November, p 18 ). But methane is a great biofuel that is relatively easy to make, store and transport. Sensibly, three times more UK domestic energy …

I am pleased by the progress in planning new homes that Vaughan outlines. But the suggestion that a space can be "airtight, but still well-ventilated" is confusing. Should air trapped in an airtight home be recirculated? How would moisture escape? Dehumidifiers need electricity and moisture-absorptive materials have to be recharged (more electricity consumption) or replaced …

Matthew Allan proposes that we retrofit homes with integrated heat-handling equipment ( Letters , 26 October ). This is a great idea. We already have a sealed house. Its controlled ventilation incorporates a heat exchanger working at 92 per cent efficiency. The only heat we waste is water from washing machines and showers. These use …

You report the pollution and possible health risks of plastic particles from teabags ( 5 October, p 16 ). There is a simple way to avoid these: stop using teabags. For the price of a box of teabags that makes 25 cups, I buy loose tea to make 250 cups.