Posted inPhotographs Indentured “Coolies” Mining Guano (1800s) May 23, 2023 Indentured “coolies” mining guano. Smithsonian National Museum of American History. Thomas Waters Jr. would’ve observed this process from his ship, Wealth of Nations, which made more than one trip to the Guañape Islands to bring guano back to England, where it was highly prized as a fertilizer. Public domain, via Wikimedia Commons. See also P. 278 of the By Sea, By Land book. PRINT