of the factory and the farm
enormously multiplies bodily skill and vigor. Countless trained
intelligences are at work to teach us how to avoid or counteract the
effects of waste. Of course some of the agents in the modern
scientific development of natural resources deal with resources of
such a kind that their development means their destruction, so that
exploitation on a grand scale means an intense rapidity of development
purchased at the cost of a speedy exhaustion. The enormous and
constantly increasing output of coal and iron necessarily means the
approach of the day when our children's children, or their children's
children, shall dwell in an ironless age--and, later on, in an age
without coal--and will have to try to invent or develop new sources
for the production of heat and use of energy. But as regards many
another natural resource, scientific civilization teaches us how to
preserve it through use. The best use of field and forest will leave
them decade by decade, century by century, more fruitful; and we have
barely begun to use the indestructible power that comes from harnessed
water. The conquests of surgery, of medicine, the conquests in the
entire field of hygiene and sanitation, have been literally
marvellous; the advances in the past century or two have been over
more ground than was covered during the entire previous history of the
human race.

The advances in the realm of pure intellect have been of equal note,
and they have been both intensive and extensive. Great virgin fields
of learning and wisdom have been discovered by the few, and at the
same time knowledge has spread among the many to a degree never
dreamed of before. Old men among us have seen in their own generation
the rise of the first rational science of the evolution of life. The
astronomer and the chemist, the psychologist and the historian, and
all their brethren in many different fields of wide endeavor, work
with a training and knowledge and method which are in effect
instruments of precision, differentiating their labors from the labors
of their predecessors as the rifle is differentiated from the bow.

The play of new forces is as evident in the moral and spiritual world
as in the world of the mind and the body. Forces for good and forces
for evil are everywhere evident, each acting with a hundred- or a
thousand-fold the intensity with which it acted in former ages. Over
the whole earth the swing of the pendulum grows more and