Networks of Science: Charles Darwin, Leonard Jenyns & Hewett Cottrell Watson

February 12, 2020

Happy birthday to Charles Darwin, whose theory of evolution by natural selection is central to our understanding of life on Earth. To celebrate, we thought it might be interesting to look at two books by scientists whose lives and work were interwoven with his, and who, along with hundreds of other researchers and observers, contributed to the development of his great theory.

The first is Leonard Jenyns (1800-1893), who was considered a “patriarch of natural history studies in Great Britain” (ODNB), and who made a decision that would dramatically change the course of Darwin's career.

Interested in science from a young age, Jenyns attended Cambridge, where he became a close friend and collaborator with J. S. Henslow, Darwin's mentor. In 1823 Jenyns was ordained, and his first post was as curate of Swaffam Bulbeck, where he began making daily meteorological observations that were published as Observations in Meteorology in 1858. This book is still useful today as a source for understanding past weather, particularly how global warming is altering the British climate.

Jenyns was a tireless observer, and made numerous other contributions to the field of natural history. Among his most important publications were A Systematic Catalogue of British Vertebrate Animals (1835) and A Manual of British Vertebrate Animals (1835); “the latter work was held in high estimation as a work of reference” (ODNB).

Living near Cambridge while Darwin was an undergraduate, Jenyns became friends with the younger naturalist. Their relationship was apparently strained at first, when Jenyns refused to share insect specimens, but over time the two grew closer, with Darwin reporting to his cousin that "I have seen lots of him lately, & the more I see the more I like him" (Pauly, Darwin's Fishes, p. 118).

Most famously, Jenyns was invited to join the Beagle voyage, but declined and recommended Darwin instead, later writing that, “no better man could have been chosen for the purpose” (Darwin Correspondence project biographical sketch). Jenyns remained involved with the voyage, though, cataloguing the fish specimens that Darwin collected on his journey, culminating in the important publication Fishes of the Zoology of the Voyage of the Beagle, published between 1840 and 1842.

Darwin and Jenyns remained friends and correspondents for the rest of their lives, and Jenyns was supportive when his friend's theory of evolution by natural selection was made public in 1858. While researching the theory Darwin frequently sought material on species variation from other scientists, and just two years previously, had "requested a copy of a paper entitled 'the variation of species' which Jenyns read at a meeting of the British Association for the Advancement of Science" (ODNB).

Another scientist tapped for his expertise by Darwin was Hewett Cottrell Watson (1804-1881).

Inspired by the work of Alexander von Humboldt, Watson became Britain's leading phytogeographer — one who studies the geographical distribution of plants. "By 1834 he was also a Lamarckian transmutationist, and he hoped that close attention to specimens collected in different parts of a species' range might provide evidence supporting transmutation" (ODNB).

Watson's most significant contributions to science were the botanical specimen exchange clubs he developed, and his three books on phytogeography. Outlines of the Geographical Distribution of British Plants, was published in 1832 and then expanded into Cybele Britannica, or, British Plants, and their Geographical Relations (4 volumes published between 1847 and 1859). The summary of his life's work was published in two volumes as Topographical Botany: being Local and Personal Records towards shewing the Distribution of British Plants (1873-74):

Our copy of this important work is inscribed by Hewett in each volume in their years of publication:

Darwin and Watson had ever met, but in 1844 Darwin became interested in Watson's published work on the plants of the Azores, as well as his review of The Vestiges of the Natural History of Creation, a troubled precursor to Darwin's own theories. Darwin planned to contact Watson personally, but was dissuaded when Watson publicly and aggressively challenged a friend, Edward Forbes, over a perceived lack of credit for ideas used in a talk. The men's mutual friend Joseph Hooker stepped in and discreetly "asked Darwin's questions for him without mentioning their source. Hooker sent Watson's lengthy reply to Darwin, who used it in The Origin of Species (ODNB).

"Forbes died on 18 November 1854, and nine months later Darwin wrote directly to WatsonWatson then wrote Darwin about eight letters in 1855 answering questions on the geographic distributions and variability of British species... Darwin warmly acknowledged Watson's assistance, but since On the Origin of Species (1859) appeared with little documentation, few readers understood what Watson had contributed. Furthermore, when Darwin added a historical preface to the 1861 edition, he forgot to mention Watson. After reading the OriginWatson wrote to Darwin that he was 'the greatest Revolutionist in natural history of this century, if not of all centuries' (Watson to Darwin, 21 Nov 1859). Later, however, he doubted the sufficiency of natural selection to account for all aspects of evolution" (ODNB).

What's particularly interesting about Jenyns and Watson is how their interactions with Darwin highlight the dense web of connections between researchers. Darwin was a great thinker who made enormous contributions to science, but he relied on the work of many others — academics, farmers, animal breeders, and amateur nature enthusiasts — to provide and refine the data that built the theory of natural selection. We can see the origins of modern, international projects, such as the decoding of the human genome and the operation of the Large Hadron Collider, in the community of natural historians who made On the Origin of Species possible.