In contrast in England the majority of people, until quite close to 1800, lived in dwellings with beaten earth floors covered by rushes that were only infrequently renewed. Into these rushes went deposits of waste food, urine, and spit. Indeed the effluvium deposited on floors from ordinary household business was so rich that, when saltpeter men were empowered in the late sixteenth and early seventeenth centuries to dig out the earth floors as rich sources of saltpeter (potassium nitrate), they allegedly dug up not just barn floors but also the floors of houses. 引自 5
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