The book was a potpourri of interesting facts, absurd factoids, savvy insights, tenuous suppositions, and woozy deductive leaps, which variously satisfied or amused readers ranging from Queen Victoria to John Stuart Mill to Florence Nightingale. Darwin thought it shaky at best. Wallace, younger and more impressionable, saw in it "an ingenious hypothesis" yet to be proved, or maybe not, by further research. For him Vestiges represented both "an incitement" to gather natural history data and a provisional theory against which new data could be tested. Thus incited, he and his friend Bates cooked up a plan to go to the Amazon rain forest in quest of such data.
Having almost no money, they paid their expenses by shipping back natural history specimens for sale to museums and private fanciers. Butterflies, beetles, and birds were mostly what was wanted, and if the creatures were both rare and gorgeous, all the better. Their agent was Samuel Stevens, of Bloomsbury Street in London, a faithful man who would play an enduring role in Wallace's life, linking him to the buyers and eventually to the scientists of England.
Wallace's four-year saga in the Amazon—exploring remote headwater regions along the Rio Uaupés and elsewhere (while Bates traveled separately), making observations, gathering specimens, taking notes, drawing sketches—was a triumph of persistence, invaluable as a training exercise but ending in disaster. He sailed home from Pará (Belém), Brazil, in August 1852, aboard the Helen, which caught fire and sank. Wallace survived in a lifeboat, but all the collections he'd brought with him, comprising thousands of insects and probably hundreds of bird skins, were gone. Then the ship by which he was rescued, a dubious tub called the Jordeson, met a harrowing storm and almost sank too. "Fifty times since I left Pará have I vowed," Wallace wrote to a friend, "if I once reached England, never to trust myself more on the oceans. But good resolutions soon fade." Within days of limping ashore, Wallace had begun planning his next trip. This time he would go east, into a world of islands.
His long expedition to the Malay Archipelago was a much different matter, far more fruitful in its yield of specimens and ideas. Wallace arrived at Singapore in April 1854 and spent the next eight years zigzagging among the islands, traveling by every sort of boat, from mail steamer to merchant schooner to dugout canoe. Onshore, he lived as the local people lived, sheltering in thatched houses and eating whatever could be traded for or bought. He made stops on Sumatra, Java, Bali, Lombock, Borneo, Celebes, Gilolo, Ternate, Batchian, Timor, Ceram, a little cluster of islands called Aru at the eastern extremity of the archipelago, and the Vogelkop peninsula of New Guinea. He sailed close past the island of Komodo (but despite his search for notable fauna, remained unaware of the existence of Komodo dragons). In some places, such as Sarawak and Aru, he lingered for months, netting butterflies and grabbing beetles in the nearby forests, shooting birds, or else simply processing his specimens and his impressions, healing his infected feet, recovering from bouts of malaria, waiting for the rains to end or the winds to shift. He learned enough of the Malay language to do business in remote locales. He hired a Bornean boy named Ali to help with bird shooting and other chores. Everywhere he went, he collected, preparing and packaging his insects and bird skins and mammal pelts with great care, keeping them with him until he reached a port, then shipping consignments to Samuel Stevens back in London. From little Aru alone, with its birds of paradise and other special attractions, he brought away more than 9,000 specimens, representing 1,600 different species, more than a few of those new to science. He figured the whole lot might be worth £500. Stevens sold it for twice that—amounting to about $100,000 in today's value.