current was turned on slowly so as to prevent the cracking of the
button. The button was heated to the point of fusion, and when it
melted it did not, apparently, glow with the same brilliancy as
before, and this would indicate a lower temperature. Leaving out of
consideration the observer's possible, and even probable, error, the
question is, can a body under these conditions be brought from a solid
to a liquid state with evolution of _less_ light?
When the potential of a body is rapidly alternated it is certain that
the structure is jarred. When the potential is very high, although the
vibrations may be few--say 20,000 per second--the effect upon the
structure may be considerable. Suppose, for example, that a ruby is
melted into a drop by a steady application of energy. When it forms a
drop it will emit visible and invisible waves, which will be in a
definite ratio, and to the eye the drop will appear to be of a certain
brilliancy. Next, suppose we diminish to any degree we choose the
energy steadily supplied, and, instead, supply energy which rises and
falls according to a certain law. Now, when the drop is formed, there
will be emitted from it three different kinds of vibrations--the
ordinary visible, and two kinds of invisible waves: that is, the
ordinary dark waves of all lengths, and, in addition, waves of a well
defined character. The latter would not exist by a steady supply of
the energy; still they help to jar and loosen the structure. If this
really be the case, then the ruby drop will emit relatively less
visible and more invisible waves than before. Thus it would seem that
when a platinum wire, for instance, is fused by currents alternating
with extreme rapidity, it emits at the point of fusion less light and
more invisible radiation than it does when melted by a steady current,
though the total energy used up in the process of fusion is the same
in both cases. Or, to cite another example, a lamp filament is not
capable of withstanding as long with currents of extreme frequency as
it does with steady currents, assuming that it be worked at the same
luminous intensity. This means that for rapidly alternating currents
the filament should be shorter and thicker. The higher the
frequency--that is, the greater the departure from the steady
flow--the worse it would be for the filament. But if the truth of this
remark were demonstrated, it would be erroneous to conclude that such
a refractory button as used in these bulbs would be deteriorated
quicker by currents of extremely high frequency than by steady or low
frequency currents. From experience I may say that just the opposite
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