Quartz Sand: Washed and Burnt Glass Sand (Pellatt, 1849)

How an English flint-glass house made its sand fit for glass in 1849: Isle of Wight sand, low in iron, washed by hand in about eight waters to take out chalk and other impurities, dried or burnt in a heated arch called a calker, then sifted through a lawn sieve. The washing takes away about one fifth of the sand's bulk. Source: Apsley Pellatt, Curiosities of Glass Making (1849), pp. 35-36. Picture: the book's text.