I cannot remember what papers have given me the impression, but I have that, which you state to be the case, firmly fixed on my mind, namely, the little chemical importance of the soil to its vegetation. What a strong fact it is, as R. Brown once remarked to me, of certain plants being calcareous ones here, which are not so under a more favourable climate on the Continent, or the reverse, for I forget which; but you, no doubt, will know to what I refer. By-the-way, there are some such cases in Herbert's paper in the 'Horticultural Journal.' ('Journal of the Horticultural Society,' 1846.) Have you read it: it struck me as extremely original, and bears DIRECTLY on your present researches. (Sir J.D. Hooker was at this time attending to polymorphism, variability, etc.) To a NON-BOTANIST the chalk has the most peculiar aspect of any flora in England; why will you not come here to make your observations? WE go to Southampton, if my courage and stomach do not fail, for the Brit. Assoc. (Do you not consider it your duty to be there?) And why cannot you come here afterward and WORK?... THE MONOGRAPH OF THE CIRRIPEDIA, October 1846 to October 1854. [Writing to Sir J.D. Hooker in 1845, my father says: "I hope this next summer to finish my South American Geology, then to get out a little Zoology, and hurrah for my species work..." This passage serves to show that he had at this time no intention of making an exhaustive study of the Cirripedes. Indeed it would seem that his original intention was, as I learn from Sir J.D. Hooker, merely to work out one special problem. This is quite in keeping with the following passage in the Autobiography: "When on the coast of Chile, I found a most curious form, which burrowed into the shells of Concholepas, and which differed so much from all other Cirripedes that I had to form a new sub-order for its sole reception...To understand the structure of my new Cirripede I had to examine and dissect many of the common forms; and this gradually led me on to take up the whole group." In later years he seems to have felt some doubt as to the value of these eight years of work,--for instance when he wrote in his Autobiography--"My work was of considerable use to me, when I had to discuss in the 'Origin of Species,' the principles of a natural classification. Nevertheless I doubt whether the work was worth the consumption of so much time." Yet I learn from Sir J.D. Hooker that he certainly recognised at the time its value to himself as systematic training. Sir Joseph writes to me: "Your father recognised three stages in his career as a biologist: the mere collector at Cambridge; the collector and observer in the "Beagle", and for some years afterwards; and the trained naturalist after, and only after the Cirripede work. That he was a thinker all along is true enough, and there is a vast deal in his writings previous to the Cirripedes that a trained naturalist could but emulate...He often