Abstract: A self-locking dual worm gear with parallel axes and linear contact for the worms with involute herringbone gears is characterized by the fact that the cross sections for curvature radii p.sub.nm1 and p.sub.nm2 and the longitudinal sections for curvature radii p.sub.xm1 and p.sub.xm2 of the worm profile are always determined at the point of contact M for the teeth and with the following equations:p.sub.nm1 =p.sub.tm1 /cos .beta..sub.B1 ; p.sub.nm2 =p.sub.tm2 /cos .beta..sub.B2p.sub.xm1 =p.sub.nm1 .multidot.sin .beta..sub.B1 =p.sub.tm1 .multidot.g.beta..sub.B1 ; p.sub.xm2 =p.sub.nm2 .multidot.sin .beta..sub.B2 =p.sub.tm2 .multidot.tg.beta..sub.B2wherein p.sub.tm1 and p.sub.tm2 represent the curvature radii of an involute profile in the cross section at contact point M and .beta..sub.B1 and .beta..sub.B2 are the tooth edge inclinations for the worms with ##EQU1## wherein r.sub.m1 and r.sub.m2 represent the operational radii for the circles, which run through contact point M and r.sub.B1 and r.sub.

Abstract: A method of recovering gold from an ore containing micron gold or gold dust is disclosed. The gold is recovered by providing a silver coated surface, coating the silver coated surface with mercury, washing a mixture of ore and water over the mercury such that an amalgam of gold and mercury is created on the silver coated surface, removing the amalgam from the silver coated surface, and heating the amalgam. The same method may be used to recover platinum from an ore containing micron platinum or platinum dust and also to recover silver from an ore containing micron silver or silver dust.

Abstract: A process and apparatus for extracting gold fines and other precious metals dissolved or suspended in water and not usually visible to the naked eye by circulating a stream of water determined to contain such gold fines and the like downwardly through a tank and into contact with electrostatically charged particles of mercury thereby causing any gold or other precious metals in the water to react with the mercury forming amalgams. The gold and other precious metals may then be separated from the amalgams by any suitable techniques known in the art.