"When the publishers asked me to write the Life of Watt, I declined, stating that my thoughts were upon other matters. This settled the question, as I supposed, but in this I was mistaken. Why shouldn't I write the Life of the maker of the steam-engine, out of which I had made fortune? Besides, I knew little of the history of the Steam Engine and of Watt himself, and the surest way to obtain knowledge was to comply with the publisher's highly complimentary request. In short, the subject would not down, and finally, I was compelled to write again, telling them that the idea haunted me, and if they still desired me to undertake it, I should do so with my heart in the task.