The American next to me is in transcribing formulae for posset and gooseberry wine from a Middle English receiptboke. I go to the enquiries counter for some pointless request. As I wait, a young gentleman receives his book from Special Collections. It comes in a little packet, and when he pulls it out, I can see that it is smaller than his thumbnail. The look on his face, somewhere between surprise and annoyance, is priceless. He tries, momentarily, to read it, but is briskly defeated, and returns it to the counter. Curious, I order it myself. It turns out to be an 1896 Salmin edition of Galileo's Letter to Cristina (1615), 15 x 9 mm.