limit of the elements, though
it is possible that elements may be found beyond it just as the planet
Neptune was discovered outside the orbit of Uranus. Considering the
position of uranium and its numerous progeny as mentioned above, it is
quite appropriate that this element should bear the name of the father
of all the gods.

In these radioactive elements we have come upon sources of energy such
as was never dreamed of in our philosophy. The most striking peculiarity
of radium is that it is always a little warmer than its surroundings, no
matter how warm these may be. Slowly, spontaneously and continuously,
it decomposes and we know no way of hastening or of checking it. Whether
it is cooled in liquefied air or heated to its melting point the change
goes on just the same. An ounce of radium salt will give out enough heat
in one hour to melt an ounce of ice and in the next hour will raise this
water to the boiling point, and so on again and again without cessation
for years, a fire without fuel, a realization of the philosopher's lamp
that the alchemists sought in vain. The total energy so emitted is
millions of times greater than that produced by any chemical combination
such as the union of oxygen and hydrogen to form water. From the heavy
white salt there is continually rising a faint fire-mist like the
will-o'-the-wisp over a swamp. This gas is known as the emanation or
niton, "the shining one." A pound of niton would give off energy at the
rate of 23,000 horsepower; fine stuff to run a steamer, one would think,
but we must remember that it does not last. By the sixth day the power
would have fallen off by half. Besides, no one would dare to serve as
engineer, for the radiation will rot away the flesh of a living man who
comes near it, causing gnawing ulcers or curing them. It will not only
break down the complex and delicate molecules of organic matter but will
attack the atom itself, changing, it is believed, one element into
another, again the fulfilment of a dream of the alchemists. And its
rays, unseen and unfelt by us, are yet strong enough to penetrate an
armorplate and photograph what is behind it.

But radium is not the most mysterious of the elements but the least so.
It is giving out the secret that the other elements have kept. It
suggests to us that all the other elements in proportion to their weight
have concealed within them similar stores of energy. Astronomers have
long dazzled our imaginations by