Page:Popular Science Monthly Volume 92.djvu/98

From Wikisource
Jump to navigation Jump to search
This page needs to be proofread.

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 whicli-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

82

��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

�� �