I first saw Williamson on February 16, 1883, when I attended his Friday evening lecture at the Royal Institution, "On some anomalous Oolitic and Palaeozoic Forms of Vegetation." I did not, however, make his acquaintance till six years later, when we met at the British Association Meeting at Newcastle-upon-Tyne, in 1889. This led to a visit to his house in company with Prof. Bower; it was on March 8, 1890, that I first had a sight of his collection. I find the entry in my diary: "Spent 7 hours over fossils, especially _Lyginodendron_ and _Lepidodendron_, preparations magnificent." I at once became an ardent convert to the cult of fossil plants to which I had hitherto been indifferent, though I must in fairness admit that Count Solms-Laubach's _Einleitung_ had done something to prepare the way. I well remember the state of enthusiasm in which I returned home from Manchester. A subsequent visit confirmed me in the faith, but it was some little time before I put my convictions into practice. In 1892 Williamson, then in his 76th year, resigned the Manchester Professorship and came to live near London. In the same year I migrated to Kew, and it was agreed that we should work in concert, an arrangement which received every encouragement from the then Director, Thiselton-Dyer. Williamson first came to the Jodrell Laboratory on Friday, December 2, 1892. Then, and on many later visits, he carried a satchel over his shoulder, crammed with the treasures of his collection. For some months he came pretty regularly once a week, afterwards less often. On these visits we discussed the work I had done on the sections during the interval, and sometimes our discussions were decidedly lively. In the end, however, we always managed to come to a satisfactory agreement. Our first joint paper (_Calamites_, _Calamostachys_ and _Sphenophyllum_) was sent off to the Royal Society, rather more than a year from the start, on December 29, 1893. During the early part of 1894 Williamson came occasionally to Kew, and our discussions were renewed, this time chiefly on _Lyginodendron_. Our second paper (Roots of Calamites) was despatched on October 30, 1894. After a considerable interval Williamson again visited Kew, on December 12, 1894, when we started on his _Lepidodendron_ sections, a subject on which we never published in conjunction. His last visit was on January 7, 1895. A few days later his health broke down, and though there were many fluctuations he was never able to come to the laboratory again. I saw him last, at his own house, on June 4th. On the 13th I read our joint paper on _Lyginodendron_ and _Heterangium_ at the Royal Society; on the 23rd he passed peacefully away.