ing nests after the same pattern and migrating over the
same territories. But man investigates, ponders, experiments, improves.

This principle of experiment--the appeal to trial and error--holds true
of social as well as of individual life. The hunter tries out a new
snare or weapon, the machinist constructs a new tool, the chemist works
out a new formula, the architect creates a new variety of arch or
buttress, the educator writes a new kind of text-book, the sanitary
engineer devises new methods for securing and safeguarding a water
supply, the statesman plans a new system of roads that will open up the
rural districts, the social scientist draws the design for a new type of
economic organization. From the most personal to the most social, from
the most local to the most general or universal, human activities are
directed over new fields and into new channels on the principle of
experiment, by the method of trial and error.

The scientist or inventor works in his laboratory or in his shop,
devoting his energies to investigation and research which are nothing
more than the application of the principle of trial and error to the
particular problems with which his science is confronted. Once the
experimenter has discovered a way to compel mechanical power to toil for
man, or to destroy the typhoid germ, or to talk across a continent
without wires, the next task is to find a better way or an easier way.
Far from decreasing the necessity for experiment, each new discovery in
the realm of natural science opens the door to additional possibilities.
To-day every important college, most cities, many industries, and public
institutions maintain experimental laboratories in the various fields of
applied knowledge, and employ highly trained experts whose sole duty it
is to try things out.

Inventors frequently hit upon new ideas or upon novel devices by chance,
but for every such chance discovery, there are scores and probably
hundreds of ideas and devices that have been carefully thought out,
worked over, rejected, revised, modified, until they produced the
desired results. There is a margin of chance in all experiment, but
surrounding it there is a vast field of careful thinking and planning
and of endless purposeful endeavor.

These observations are commonplaces in the laboratory and in the
department of research. They have filtered through to thinking people
who begin to understand the part that experiment plays in all for