Kate, you’re lying on a sofa and asking me questions sometimes, sometimes making comments – a sofa, which is covered by a periodic table quilt. I am surrounded by periodic tables in different forms. You also have periodic table cushions there. I have periodic table T-shirts. I have periodic table socks. I wish I were wearing them. But when my gaze strays, I see an unobscured portion of the periodic table, with arsenic and selenium and bromine and tellurium and iodine there, and as I look I think of stories associated with all of these elements.  For example, how... how Humphry Davy, who discovered chorine and iodine, realised there must be an element in between them. In fact, he... it was discovered 15 years later. And... but one of the things I wondered about writing about, as I was writing Uncle Tungsten, was a... a child’s book of the elements.

For me growing up, a book I loved was by Mary Elvira Weeks. It was called Discovery of the Elements. And the properties of elements, but the lives of their discoverers, affected me greatly, and it still affects me greatly. I... when I gave my sister-in-law... I had her sent a sample of thulium for her 69^th birthday, I thought of a story of Mary Elvira Weeks, of how Auer von Welsbach, realise... who discovered and worked on many of the rare earth elements, on his last day…  I don’t know what happened, maybe an aneurism had started leaking inside him. He... he knew he only had a few hours, and he walked slowly up to his own laboratory. And Weeks describes how he pulled the cover over the spectroscope, looked at his samples of thulium, which were the last thing he worked on, which he would have to leave unfinished, came downstairs, gazed at a portrait of his father for a minute, and then went to bed and died.

I mean, so that is a thulium story. There are many thulium stories. Perhaps, some time when I don’t feel there are things I need to do more urgently, I should write a child’s book of the elements. It’s the only sort of children’s book I have any impulse to read... I’m sorry, I have any impulse to write. That might have been a Freudian error.