Radium, as we understand it in any of its compounds, can communicate
its property of radio-activity to other bodies. Any material when
placed near radium becomes radio-active and retains such activity for
a considerable time after being removed. Even the human body takes on
this excited activity and this sometimes leads to annoyances as in
delicate experiments the results may be nullified by the element acting
upon the experimenter's person.

Despite the enormous amount of energy given off by radium it seems not
to change in itself, there is no appreciable loss in weight nor
apparently any microscopic or chemical change in the original body.
Professor Becquerel has stated that if a square centimeter of surface
was covered by chemically pure radium it would lose but one thousandth
of a milligram in weight in a million years' time.

Radium is a body which gives out energy continuously and spontaneously.
This liberation of energy is manifested in the different effects of
its radiation and emanation, and especially in the development of heat.
Now, according to the most fundamental principles of modern science,
the universe contains a certain definite provision of energy which can
appear under various forms, but which cannot be increased. According
to Sir Oliver Lodge every cubic millimeter of ether contains as much
energy as would be developed by a million horse power station working
continuously far forty thousand years. This assertion is probably based
on the fact that every corpuscle in the ether vibrates with the speed
of light or about 186,000 miles a second.

It was formerly believed that the atom was the smallest sub-division
in nature. Scientists held to the atomic theory for a long time, but