Abstract
Since a long time in Japan, magnetic iron sand was treated in a low furnace with charcoal, and heavy mass of iron bear thus produce 1, about 3-4 tons in weight, was broken up to small piec s. They are sorted into several kinds, according to their own hardness Their chemical compositions are very pure, low in sulphur and phosphorus. The original sands having pret'y rich coutents of those elements, the author proposes in this paper the liquation theory p. evailing in the bottom of furnace to explain this fact.