Henry Walter Bates(1825–1892)

Henry Walter Bates was born at Leicester in February 1825, eldest son of a hosier who ran a stocking-frame workshop in the town. He was schooled briefly at the Reverend William Stamford's day school, taken out of school at thirteen and apprenticed to his father's trade at a knitwear warehouse on Granby Street. The hours were six in the morning to eight at night. He read on his own time, at the Mechanics' Institute on Wellington Street, where the books and the natural-history specimens of the Leicester Literary and Philosophical Society opened the second life of his evenings and Sundays. He was collecting beetles on the canal towpath at Wigston by sixteen and corresponding with the entomologists at the Linnean Society in London by nineteen. He met Alfred Russel Wallace, who had come to Leicester as a schoolmaster, at the Mechanics' Institute Library in 1844; the friendship that resulted, between the assistant master and the warehouseman's apprentice, was the foundation of both their later careers.

Wallace had read William Henry Edwards's 1847 *A Voyage Up the River Amazon* and was on fire to go. Bates was the natural partner. They sold their existing collections to fund the outward passage and the early months in the field; they signed an arrangement with the natural-history dealer Samuel Stevens at Bedford Street, Covent Garden to receive their consignments of specimens and to sell them to the museums and private collectors who would in effect be funding the rest of the expedition. They sailed from Liverpool aboard the *Mischief* on 26 April 1848 and reached Pará (Belém) at the mouth of the Amazon on 28 May. Bates was twenty-three. Wallace was twenty-five. They worked together for the first eighteen months around Pará, then parted by mutual agreement so that each could cover the river's tributaries on his own line; Wallace went up the Rio Negro and the Orinoco, lost his collections in a fire at sea on the return passage in 1852, and was home before the end of the decade. Bates stayed.

He worked the Amazon for eleven years to 1859. From Pará up to Santarém, then up the Tapajós into the Mato Grosso interior, then back to the main stream and up the Solimões to Ega (Tefé) on the upper Amazon, then four years of base-camp work at Ega from which he made the collecting trips into the Japurá, the Içá and the Tonantins. He was, for most of the eleven years, the only European on the upper Amazon. He learned the Tupi-Lingoa-Geral trade pidgin and conversational Portuguese, took fevers (the most serious left him deaf in one ear), lost most of his teeth to a malaria-related calcium deficiency, and accumulated specimens. He shipped Stevens, over the period, fourteen thousand species new to science, mostly insects, mostly beetles and butterflies, with substantial collections also of birds, reptiles, and freshwater fish. The shipping list is the largest single collection by a single collector of nineteenth-century natural history.

He came home in June 1859, sat down at his mother's house in Leicester to write up the field notebooks, and in 1861 read to the Linnean Society the paper that gave evolutionary biology its first independent field-evidence: *Contributions to an Insect Fauna of the Amazon Valley*. The paper described what would become known as Batesian mimicry, the phenomenon by which an edible butterfly species evolves wing-pattern resemblance to a separate inedible species that the local birds have learned to avoid, with the consequence that the mimic gains the protection of the model without the cost of producing the toxins. The mechanism required natural selection to be the explanatory engine; Bates explicitly said so in the paper. The reading was on 21 November 1861, two years after Darwin's *Origin of Species*, and Darwin, who had been corresponding with Bates since 1860, read the paper before it was given and called it in his review for the *Natural History Review* in 1863 *one of the most remarkable and admirable papers I ever read in my life*. The two-volume travel narrative *The Naturalist on the River Amazons*, published by John Murray in 1863, sold well and is the foundation document of English-language Amazonian natural history.

He was appointed assistant secretary of the Royal Geographical Society on Darwin's recommendation in 1864 and held the post for the rest of his life, twenty-eight years of administering the Society's expeditionary work through the great age of African and Arctic exploration. He published nothing else of note: the eleven Amazon years were the work. He married Sarah Ann Mason of Leicester in 1861 (it was the only domestic life he had); they had four children; he lived at Dulwich and went to the Society's rooms in Savile Row six days a week. He was elected a Fellow of the Royal Society in 1881 and died at his Dulwich house on 16 February 1892, sixty-seven years old, of complications from the Amazon fevers that had never fully left him. The Bates name in its English-side form, the patronymic of Bartholomew compressed into the northern -s genitive, sits otherwise in the Cumbria-to-Humber belt; he carried it from a Leicester knitwear warehouse into the foundation period of evolutionary biology.