We are creatures of light and air. Life’s a gas, in every sense. We are oxygen, hydrogen and nitrogen, packed together with the carbon that photosynthesising life has plucked, one molecule at a time, from the atmosphere in the form of carbon dioxide. At cremation, our bodies bake down to a handful of minerals. When Hamlet beseeched his too, too solid flesh to melt, thaw and resolve itself into a dew, he got it about right: the Prince of Denmark would have been about 70% water, which is itself an atmospheric vapour. And he certainly could have been blown away. Harry Truman – “not that Harry Truman”, as Sam Kean says in this bright and breezy book – was blown away by Mount St Helens. Truman was the defiant man who dismissed the warnings of volcanologists and refused to leave the high slopes of America’s most violent modern volcano before it erupted in May 1980. Kean reconstructs his death because, as a chemist, he knows the temperatures at which water, viscera and bones could vaporise as a black cloud of intense heat, 100 storeys high and 10 miles wide, came roaring down the mountain at 350mph: “Truman’s clothes would […]