Up to the time of his last illness, he regularly breakfasted at eight, and avoided, as far as possible, going out to that meal, a "detestable habit" as he called it, which put him off for the whole day. He left the house about nine, and from that time till midnight at earliest was incessantly busy. His regular lectures involved an immensity of labour, for he would never make a statement in them which he had not personally verified by experiment. In the Jermyn Street days he habitually made preparations to illustrate the points on which he was lecturing, for his students had no laboratory in which to work out the things for themselves. His lectures to working-men also involved as much careful preparation as the more conspicuous discourses at the Royal Institution. This thoroughness of preparation had no less effect on the teacher than on the taught. He writes to an old pupil:--] It is pleasant when the "bread cast upon the water" returns after many days; and if the crumbs given in my lectures have had anything to do with the success on which I congratulate you, I am very glad. I used to say of my own lectures that if nobody else learned anything from them, I did; because I always took a great deal of pains over them. But it is none the less satisfactory to find that there WERE other learners. [As for the ordinary course of a day's work, the more fitful energy and useless mornings of the earliest period in London were soon left behind. He was never one of those portentously early risers who do a fair day's work before other people are up; there was only one period, about 1873, when he had to be specially careful of his health, and, under Sir Andrew Clark's regime, took riding exercise for an hour each day before starting for South Kensington, that he records the fact of doing any work before breakfast, and that was letter-writing. Much of the day during the session, and still more when his lectures were over, would thus be spent in original research, or in the examination and description of fossils in his official duty as Paleontologist to the Survey. As often as not, there would be a sitting of some Royal Commission to attend; committees of some learned society; meetings or dinners in the evening; if not, there would be an article to write or proofs to correct. Indeed, the greater part of the work by which the world knows him best was done after dinner, and after a long day's work in the lecture-room and laboratory. He possessed a wonderful faculty for tearing out the heart of a book, reading it through at a gallop, but knowing what it said on all the points that interested him. Of verbal memory he had very little; in spite of all his reading I do not believe he knew half a dozen consecutive lines of poetry by heart. What he did know was the substance of what an author had written; how it fitted into his own scheme of knowledge; and where to find any point again when he wished to cite it.