Sawdust, slabs, stumps and large quantities of logs are wasted.
This insulation generally consists of materials such as charcoal, silicate cotton, granulated cork, small pumice, hair-felt, sawdust, &c., held between layers of wood or brick, and forming a more or less heat-tight box.
The ground was sawdust and the pebbles scattered around were hard knots from trees, worn smooth in course of time.
It is found that the sawdust obtained from soft woods is the best material for use in this process.
Such fire-proof coverings, and also interior partitions, are composed of hollow, hard-burned terra-cotta blocks, of porous (sawdust) terra cotta, or various plastic compositions applied to metallic lath, many of which are patented both as to material and method of application.