This section is from the book "A Treatise On Architecture And Building Construction Vol2: Masonry. Carpentry. Joinery", by The Colliery Engineer Co. Also available from Amazon: A Treatise On Architecture And Building Construction.
164. Many of the common brick, especially in the smaller towns and cities, are made by hand.
The clay is thrown into a circular pit, where it is mixed with water, and tempered with sand or ashes by means of a tempering wheel, attached to a long lever and worked by horsepower. When the clay becomes soft and plastic, it is taken to the molding table and pressed into the molds by-hand.
The molds are either dipped in water (called slop molding) or in sand (called dry molding) to prevent the clay from adhering to the mold. The sand-molding process gives cleaner and sharper brick than the slop molding. After the bricks are shaped in the mold, they are laid in the sun or in a dry house for three or four days, after which they are stacked in kilns and fired.