 Moist saltpeter crystals were mixed with appropriate amounts of sulfur and charcoal by heavy rotating wheels to form a cake which was then cut unto smaller pieces in bronze- or zinc-toothed kernelling mills.The kernels were sieved into desired sizes and dried prior to being tumbled with graphite which reduced tendency for the finished grains to stick together during storage.Intermediate products were transported between the dispersed production and storage facilities in wooden wheelbarrows constructed with no iron parts and pushed over plank walkways by workmen going barefoot in the summer or wearing shoes without iron nails during colder weather.