Page:Atlantis Arisen.djvu/436



and also at Gray's Harbor, and porcelain clays in the Cowlitz Valley, never yet thoroughly tested, but abundant.

The lesson taught by the great fire of Chicago was that iron expands, cracks, twists, and gives way under heat and pressure; that granite will split and crumble if subjected to a great degree of heat and weight; that limestone will be burned into quicklime and slacked by water, or will blow out in masses, destroying a building; and that sandstone will become flaky and split off under the action of a general conflagration; but that brick made of a high-grade refractory clay, properly manufactured, will withstand the fiercest heat. Hence the value of buildingbrick produced from the refractory clays, which, mixed with those of a lower grade and burned until vitrified, can be made to withstand a heat that will melt and boil glass or steel.

The Puget Sound fire-clays vary in appearance, some of the best resembling slate and being of a blue-black color. When these are broken up and exposed to the rains of winter, they are resolved into a pasty mud, which on treatment becomes refractory. Other of the fire-clays are a bluish-gray in color, and look like stone when dry, but dissolve into paste when wet; and still others contain an excess of silica, and resemble laminated sandstone; while some are soft and oily to the touch, and of different degrees of color, from very light to very dark. As a foundation for future industries in Washington, this class of mineral substances is likely to prove of importance to the new State. An industry kindred to that of brick or pottery was carried on in 1868 by the firm of Knapp & Burrell, of Portland, on the north bank of the Columbia, at Knappton,—namely, the manufacture of cement from nodules of a yellowish limestone, found near the mouth of the river. The yield was thirtyfive barrels daily.

The precious metals are not yet at all developed in West Washington, although gold has been found in some of the streams, and alleged discoveries have been made in the Cascade and Olympic Ranges of quartz veins bearing gold and silver, both separately and in conjunction.

Gold-mining in East Washington was begun in the spring of 1855, when gold in placers was discovered near Fort Colville,