alexander von humboldt, brought it back. they are light and easy to transport. so unlike manure or nightsoil, it comes in a light, easy to transport package. another part of the story that is important to understand, to mine these guano deposits would be incredibly awful work. have any of you ever cleaned out a chicken coop? magnify that about 100 annual get an idea. this guano was incredibly acrid and dusty and get into people's lungs and make them sick. it was not work anyone wanted to do. not surprisingly, the earliest guano farmers were slaves. peru outlawed slavery in the 1850's, and it was increasingly fed by a trade in chinese labor. some of it coming from the fujian coast. about 100,000 laborers from china, semi-free labor was brought to peru. many of them ended in the chincha islands where they had to work off the cost of their transport, mining guano. it was awful work, they got paid very little. it was defeated the fertility revolution in the developed world. it is also a story about the decline of slavery and the rise of other types of global labor a