measure of the unknown material that might be causing
these rays, in the sample under examination.
By eliminating the weaker samples and concentrating
her work and attention on those that manifested these
rays in the greatest intensity, after thousands of these
tests, and nearly three years of the most exacting effort,
she found a material that was millions of times more intense
in these rays than the Uranium in which Professor Becquerel
had first, accidentally, detected them.
She called this material, —Radium.
For her years of work, self-sacrifice, and toil, with tons
of ore, she had a few thousandths of a thimbleful of material.
From this she was able, later, to obtain a pure white metal,
which had an atomic weight of 226; which melted at 700
degrees Centigrade and which when exposed to the air
quickly lost its metallic form by combining with other
materials in the atmosphere to form salts. This was the
pure Radium element.
With her Radium,—Madame Curie and her husband
soon gave the scientific world the proof that Radium introduced
 a new conception into the fundamental problems
of existence.
She proved that every three quarters of an hour the
heat from a gram, (a thimbleful) of Radium is sufficient
to change a quantity of water equal in weight to the Radium,
 from freezing to boiling point.
This was a fact that compelled and still holds the
attention of the scientific world.
This is the fact that makes Radium the most interesting
and the most important material in the earth.
Heat means energy, power, work. Heat and light may
oe obtained in many ways, but it is a new thing to find it
being given off by a substance, as it is by Radium, year in
and year out, without any apparent intermission or dimination
 and without the substance being in any way consumed
 or altered.
Before noting how the rays from Radium contribute
to the life of today and what the heat from Radium holds
of promise for the future, let us review the record of the