�鶹��ý

Michael Le Page's article barely scratches the surface of the problems with biofuel policy ( 27 July, p 23 ). Solar energy conversion involving wheat is around 0.06 per cent efficient. That is 1/250th the efficiency of the solar cells that we now see covering agricultural land. This idea takes no account of the energy …

Having worked for many years in the biomass field, I was delighted to read Le Page's article . Using biomass to produce power or fuel, when it has much more important uses, should be a crime. Politicians seem to believe that because biomass is mostly green it fits into a green future. Of course, it …

Lucia Singer refers to her teenage concerns about global warming in the 1980s and the existence even then of deniers, who nowadays attribute the undeniable warming to natural fluctuations. (Letters, 13 July ) Sadly, I was at the time one of those instinctive deniers. Being professor of ocean engineering at Newcastle University and a reader …

You report the detection by satellites of a giant seaweed patch stretching from West Africa to the Gulf of Mexico ( 13 July, p 17 ). This should be seen as good news. It is taking up nutrients and fertiliser run-off from the land and turning them, with minerals that are dissolved in seawater, into …

David Werdegar asserts we have an “absolute dependency on the signs and symbols of language” (Letters, 20 July ). That is questionable: not everybody thinks in the same way. Composers clearly think in musical terms that are sometimes difficult if not impossible to verbalise. Roger Penrose, in his 1989 book The Emperor's New Mind , …

Phil Ball suggests that Mandarin speakers think of the future as down because it matches their direction of writing (Letters, 27 July ). Even if such a correlation is found across all writing systems, it could equally be that the mapping of time to space came first. Spatial mappings can arise where there is no …

Attempts to draw water from the air, and especially the use of metal organic frameworks with their non-intuitive properties, are interesting ( 3 August, p 38 ). But what is going to happen to flora, fauna and down-wind weather patterns if large amounts of moisture are pulled from the atmosphere in already arid environments?

Sue Armstrong reported nearly a quarter of a century ago on the Maths Bus that toured South Africa ( 3 September 1994, p 6 ). Some of your readers were attracted to this educational project and volunteered on and supported the bus. I ask them to get in touch through �鶹��ý .

Leah Crane reports work on using salamander mucus to help heal wounds ( 15 June, p 19 ). This reminded me of the time my father gashed himself while working on a motorbike engine. As someone whose pharmacy training was interrupted by a spell as ground crew in the air force, he knew a remedy …

• The common name of Protonibea diacanthus is the blackspotted croaker ( 1 October 2016, p 16 ).