Around him on the table were the tools of his trade ... a tray of fountain pens and a bottle of partially evaporated black ink. The latter was Piper's own invention. Since he was writing for posterity it was essential that what he wrote should last indefinitely and without fading. For a while he had imitated Kipling in the use of Indian ink but it tended to clog his en and to dry before he could even write one word. The accidental discovery that a bottle of Waterman's Midnight Black left open in a dry room acquired a density surpassing Indian ink while still remaining sufficiently fluid to enable him to write an entire sentence without recourse to his handkerchief had led to his use of evaporated ink. It gleamed on the page with a patina that gave substance to his words, and to ensure that his work had infinite longevity he bought leather-bound ledgers.