iva voce between a man in Washington and another in Boston. The
actual attainment of these results has naturally given rise to the
belief that the word "impossible" has disappeared from our vocabulary.
To every demonstration that a result cannot be reached the answer is,
Did not one Lardner, some sixty years ago, demonstrate that a steamship
could not cross the Atlantic? If we say that for every actual discovery
there are a thousand visionary projects, we are told that, after all,
any given project may be the one out of the thousand.

In a certain way these hopeful anticipations are justified. We cannot
set any limit either to the discovery of new laws of nature or to the
ingenious combination of devices to attain results which now look
impossible. The science of to-day suggests a boundless field of
possibilities. It demonstrates that the heat which the sun radiates
upon the earth in a single day would suffice to drive all the
steamships now on the ocean and run all the machinery on the land for a
thousand years. The only difficulty is how to concentrate and utilize
this wasted energy. From the stand-point of exact science aerial
navigation is a very simple matter. We have only to find the proper
combination of such elements as weight, power, and mechanical force.
Whenever Mr. Maxim can make an engine strong and light enough, and
sails large, strong, and light enough, and devise the machinery
required to connect the sails and engine, he will fly. Science has
nothing but encouraging words for his project, so far as general
principles are concerned. Such being the case, I am not going to
maintain that we can never make it rain.

But I do maintain two propositions. If we are ever going to make it
rain, or produce any other result hitherto unattainable, we must employ
adequate means. And if any proposed means or agency is already familiar
to science, we may be able to decide beforehand whether it is adequate.
Let us grant that out of a thousand seemingly visionary projects one is
really sound. Must we try the entire thousand to find the one? By no
means. The chances are that nine hundred of them will involve no agency
that is not already fully understood, and may, therefore, be set aside
without even being tried. To this class belongs the project of
producing rain by sound. As I write, the daily journals are announcing
the brilliant success of experiments in this direction; yet I
unhesitatingly maintain that sound cannot m