103 



(b) Characteristics. 



Hardness cutting. 



Texture polish. 



Color beauty. 



Durability economy. 



Cost. 



Distribution vertical and horizontal. 



Origin igneous or aqueous. 



Quarrying location. 



2. Brick. 



Manufacture. Durability. 



Material. Brick laying. 



Kinds and colors. Advantage of brick. 



3. Wood. 



(a) Uses. 



Floors. 



Woodwork. 



Furniture. 



(b) Kinds. 



Oak. Walnut. 



Ash. Cherry. 



Maple. Birch. 



Ebony. Mahogany. 



(c) Characteristics. 



Texture. Markings. 



Grain. Color. 



Durability. Polish. 



(d) Cutting. 



Straight cut. Quarter sawed. 



VENTILATION. 



THE ATMOSPHERE. 



1. Composition mixture. 



(a) Nitrogen, four-fifths. 



(b) Oxygen, 'one-fifth. 



(c) Carbon dioxide, four-te'n thousandths. 



(d) Water, variable. , 



2. Properties. 



Invisible. Has weight. 



Colorless. Presses equally in all directions, 



Transparent. Compressible. 



Odorless. Elastic. 



3. Effects of Heat upon Ait . 



(a) Heat expands air. 



