elements
of air and water only because they are too complaisant, and deny the
foot that opposition which it requires. Precisely that, accordingly,
which makes the difficulty of an action may at the same time make its
possibility. Why is flight difficult? Because the weight of every
creature draws it toward the earth. But without this downward
proclivity, the wing of the bird would have no power upon the air.
Why is it difficult for a solid body to make rapid progress in water?
Because the water presses powerfully upon it, and at every inch of
progress must be overcome and displaced. Yet the ship is able to float
only in virtue of this same hindering pressure, and without it would not
sail, but sink. The bird and the steamer, moreover,--the one with
its wings and the other with its paddles,--apply themselves to this
hindrance to progression as their only means of making progress; so
that, were not their motion obstructed, it would be impossible.

The law governs not actions only, but all definite effects whatsoever.
If the luminiferous ether did not resist the sun's influence, it could
not be wrought into those undulations wherein light consists; if the
air did not resist the vibrations of a resonant object, and strive
to preserve its own form, the sound-waves could not be created and
propagated: if the tympanum did not resist these waves, it would not
transmit their suggestion to the brain; if any given object does not
resist the sun's rays,--in other words, reflect them,--it will not be
visible; neither can the eye mediate between any object and the brain
save by a like opposing of rays on the part of the retina.

These instances might be multiplied _ad libitum_, since there is
literally _no_ exception to the law. Observe, however, what the law is,
namely, that _some_ resistance is indispensable,--by no means that this
alone is so, or that all modes and kinds of resistance are of equal
service. Resistance and Affinity concur for all right effects; but it is
the former that, in some of its aspects, is much accused as a calamity
to man and a contumely to the universe; and of this, therefore, we
consider here.

Not all kinds of resistance are alike serviceable; yet that which is
required may not always consist with pleasure, nor even with safety. Our
most customary actions are rendered possible by forces and conditions
that inflict weariness at times upon all, and cost the lives of many.
Gravitation, forcing all men ag