A British chemist and physicist noted for his pioneering work on chemistry. From a poor Quaker family, he left his village school at the age of 11 and then taught at there from 12 to 14; from 15 he was a farm labourer. However, he began making scientific studies and even wrote a paper on his own colour-blindness. For 57 years Dalton kept a meteorological diary with over 200,000 observations. He began lecturing in Manchester and by 1800 was secretary of the Manchester Philosophical Society. He measured the rise in temperature of air when compressed and suggested in 1801 that all gases might be liquified by compressing and cooling them. After much work on vapour and gas pressures, he stated his law on partial pressures (see dalton’s law) and applying Newton’s idea of atoms in gases to his own work, formulated the law of Multiple Proportions in 1804. By 1808 he had a clear theory and published his famous Atomic Theory, which forms the basis of modern chemistry today.