Page:Popular Science Monthly Volume 92.djvu/98

 Making Millions Out of Bubbles

Huge profits, undreamed of yesterday, are now obtained from the dump pile of low-grade ores

By George Merriman Oaks

Managing Editor of the Popular Science Monthly

��MILLIONS are at stake in lawsuits brought about by infringement of the froth flotation patents. Clear- ly, they must be very important patents. In truth, they are the basis of a great industrial achieve- ment. In one mine alone the flotation method increased the daily output of zinc by 200,000 pounds; in another, the daily increase in copper was 120,000 pounds. The adoption of froth flotation by the five leading porphyry mines of the United States would mean a yearly saving of $17,000,000.

What is froth flotation? Nothing but the industrial utilization of bub- bles. Who would believe that bub- bles could be turned to money — ■

���Why Doesn't He Sink?

This water-spider Hoats, not because he is so lisht, but because of surface tension. With a little care, a needle can be floated in the same way

��yes, millions? And to think of ap- plying such ethereal objects as bub- bles, whose greatest achievement has always been to grow a little bigger and then burst, to an industry like min- ing!

It seems as though Nature's most precious gifts are often hedged about with thorns so prickly that ceaseless labor is necessary to obtain them. We find cop- per combined with sulphur as copper sulphide. Further- more, the sulphide is shaken up with all sorts of worth- less mineral mat- ter, such as sand and limestone, un- til it seems hope- lessly hidden from man's reach. The same is true of the other base metals, zinc and lead. The useless matter

U/et

��Not wet

��Wet

���Floating Bodies Are Attracted or Repelled Depending on Their Wetness

��Attraction of two bodies not wet by a lic|uid. In this instance, the pressure is the sainf at all |K)inls indicated by the dotted line, namely, that of the outside atmosphere. Pressure is also that of the atmosphere in the air space between the two bodies; but tlic water pressure on each side (in- dicated by the arrows) is greater, pushing the two bodies toward each other. Applies to sulphides in water

��Repulsion of two bodies, only one of whigh is wet by a liciuid. Pressure on left side of wet body is less than that of atmosphere which-acts on its rifiht side, pusniuK it away from the other body. Pressure 'on left ••■ide of body not wet by liquid is ureater (below surface of li(|uiil) than that of atmos- phere on riKht side. Hence the i)res- Bure of the linuid pushes the body not wet away from the other Viody

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��Attraction of two bodies wet by a liciuid. Pressure is the same at all points indicated by dotted lino, namely, that of the outside atmos- phere. Pressure is less in the liquid between the bodies and above the dotted line. Therefore, the atmos- pheric pressure outside pushes the bodies toward each other. The liquid rises between the bodies due to the principle of capillary atlraetion

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