Sodium amalgam is best made by the miner himself, enough for one clean-up at a time. Metallic sodium and quicksilver are the necessary ingredients; the former being kept in a wide-mouthed bottle covered with coal oil. A frying-pan makes a useful mixer. It must be dry and clean. Five pounds of clean mercury is poured into the pan, and dried with a sponge, and heated beyond the boiling-point of water, but not much above, or there will be a sensible loss of mercury. A piece of sodium is wiped dry, cut into 1/2-inch squares and placed with a long pair of tongs in the center of the warm quicksilver, which, by the way, is now off the fire and in the open air, the operator meanwhile keeping religiously to windward of it, unless he courts salivation and all its attendant ills. As soon as the sodium touches the mercury a flash and mild explosion will follow, but after a few cubes have been introduced into the frying-pan, always in the center, this will cease. As soon as a solid mass of amalgam forms in the middle of the pan, the contents must be stirred slowly, and a little more sodium added. The whole mass now crystallizes out, and if put into closely-stopped bottles it will keep without further protection for a little time. Once opened, each bottle must be used. Observe all these directions faithfully, then there will be no danger of inhaling mercurial fumes nor of being blown to atoms. After the amalgam is once made, it is safe as sugar. In retorting amalgam never fill the flask too full, and apply the heat gradually, and always from the top of the flask downward. The rocker is a box 40 inches long, 16 inches wide on the bottom, sloped like a cradle, and with rockers at each end. [Illustration: CROSS SECTION OF ROCKER.] A hopper 20 inches square and 4 inches deep, having an iron bottom perforated with 1/2-inch holes, occupies the top. A light canvas-covered frame is stretched under this, forming a riffle. Riffles, and occasionally amalgamated copper plates, are placed in the bottom. The gravel is fed into the hopper, the cradle being then rocked by one hand while water is fed by a dipper with the other.