Page:Popular Science Monthly Volume 64.djvu/482

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PSM V64 D482 New us dept of agriculture building.png

New buiding of the U. S. Deprtment of Agriculture, South Elevation, facing on Proposed Mall.

not recommended when an operation is practicable. Numerous other cases of the beneficial results of the radium treatment have been reported in this country and England.

More exact measurements by other observers corroborate the conclusion of Rutherford that the radiations from radium which are the least penetrating of the three types present, but represent the greater part of the energy,

PSM V64 D482 Us dept of agriculture laboratory first floor.png

Laboratories, Plan of the First Floor.

consist of positively charged particles of about twice the mass of the hydrogen atom, and moving with a velocity about one tenth that of light.

The supply of radium on the market is very uncertain. All of it is imported from France or Germany, and the price has recently been going higher. Many efforts are being made to extract radium in this country from carnotite, an ore of uranium that is found in considerable abundance in Colorado and