This section is from the "The New Student's Reference Work Volume 5: How And Why Stories" by Elinor Atkinson.
Now the Dutch had wind-mills that did the hard work of pumping water, sawing wood and grinding grain. So it was only natural that these clever people should give the wind-mills a new task of grinding kaolin, or white clay for making porcelain. The pug-mill was just a wooden vat, fed from above by a hopper filled with clay. It had an upright shaft in the middle set with rows of strong blunt knives, to cut and beat and pound the clay lumps to powder. If your mother will let you, grind up some lumps of dry kindergarten clay in the coffee mill. It won't hurt the mill, if you wash it afterwards. The powdered clay will fall into the cup or little wooden drawer at the bottom. The pug-mill in pottery works holds a ton or so of clay and is operated by steam with great wheels and flying belts and inside are broad blunt knives that turn on a shaft and chop and beat and grind. It works all the time and fills enormous bins with velvety clay flour, ready to make mud pies.
Japanese potter at his wheel, fashioning fine Kyoto ware. Hotozan, a famous porcelain worker, painting gems of art in his workshop at Kyoto.
Japanese girls, decorating fine pottery. Firing cloisonne at Takatoni factory, Kyoto, Japan.
Such lovely mud workmen make in the big tanks when the clay flour is mixed with water and stirred into a milky paste ! Think of the little china bowl you eat bread and milk from, once being an earthy milk itself, then dried to a dough and rolled and shaped and baked like the bread you put into the milk.
When mama makes real bread out of moist dough, she sprinkles dry flour on the molding board. So potters mix a dry flour with their clay dough. Such queer flour! It is ground white flint stone. This stone flour is made in a pug mill, too, but in a covered one filled with water like a washing machine. The flint rock is heated to make it crumble easily. Then it is broken up into little pieces and ground in water by a perfect giant of an iron machine that thinks nothing of making stone into flour. As fast as it is powdered this flour overflows with the water into a deep cistern vat. In that it settles to the bottom, and the water is drawn off. Then it is dried and rolled and mixed with clay dough.
Before reading any farther turn back and read the story of how land was made in the first place. Many times before, in the life of our earth, the clay and powdered stone in the hands of the potter were mud. Wind and rain and sun and frost were the grinders, rivers and lakes were settling vats, the bottom of the sea was the molding board; the water above weighed on it and pressed it into shape. And the heat at the heart of the earth melted and baked the hardest rocks. Then it was lifted above the waters, and wind, sun and rain and frost wore it down to mud again.
So in making pottery, bricks, tile, stoneware or porcelain, men only do over again what all the forces of nature do all the time. To make them into cups and plates and jars and doll-heads, the potter must grind the clay and stone again, melt them to paste in water, mix them, shape them while a soft mud or dough, put them into the fire and bake them again into a kind of stone. Isn't that wonderful? It is just as if, in making pottery, men peeped into nature's workshop, learned one of her great secrets and turned it to use.
And just as the sun sucks the water out of the hillside and leaves dust behind, so the potter sucks, or evaporates, water out of his tanks of mud with warm air. Machinery for blowing air is used for a great many things. Your lungs are a model. You use hot air from them to blow soap bubbles and to cool soup. So air blowers are used to clean carpets, to make a hotter fire in a blast furnace, to drill holes in mines, to pound rivets into iron bridges, and to dry
the water out of potter's clay. When the clay is dried to a tough dough the stone flour is kneaded in, and the potter shapes it in moulds, or turns it on a whirling, wheel-like table.
The little kindergartners have a table that doesn't move, and they shape the lumps of clay by turning them around and around. But the potter keeps the clay motionless and shapes it by whirling the table, bringing every side of the clay under his hand as he presses and shapes and hollows out the inside and smoothes the surface. Out of a lump of clay dough a lovely vase shape rises like magic under the potter's skillful hands. It looks simple, but it takes years for the potter to learn how, very quickly and perfectly, to make any shape he wishes.