But Nature makes no machines like our own.  She uses mechanical principles everywhere, in inert matter and in living bodies, but she does not use them in the bald and literal way we do.  We must divest her mechanisms of the rigidity and angularity that pertain to the works of our own hands.  Her hooks and hinges and springs and sails and coils and aeroplanes, all involve mechanical contrivances, but how differently they impress us from our own application of the same principles!  Even in inert matter—­in the dews, the rains, the winds, the tides, the snows, the streams,—­her mechanics and her chemistry and her hydrostatics and pneumatics, seem much nearer akin to life than our own.  We must remember that Nature’s machines are not human machines.  When we place our machine so that it is driven by the great universal currents,—­the wheel in the stream, the sail on the water,—­the result is much more pleasing and poetic than when propelled by artificial power.  The more machinery we get between ourselves and Nature, the farther off Nature seems.  The marvels of crystallization, the beautiful vegetable forms which the frost etches upon the stone flagging of the sidewalk, and upon the window-pane, delight us and we do not reason why.  A natural bridge pleases more than one which is the work of an engineer, yet the natural bridge can only stand when it is based upon good engineering principles.  I found at the great Colorado Canon, that the more the monuments of erosion were suggestive of human structures, or engineering and architectural works, the more I was impressed by them.  We are pleased when Nature imitates man, and we are pleased when man imitates Nature, and yet we recoil from the thought that life is only applied mechanics and chemistry.  But the thought that it is mechanics and chemistry applied by something of which they as such, form no part, some agent or principle which we call vitality, is welcome to us.  No machine we have ever made or seen can wind itself up, or has life, no chemical compound from the laboratories ever develops a bit of organic matter, and therefore we are disbelievers in the powers of these things.

V

Is gravity or chemical affinity any more real to the mind than vitality?  Both are names for mysteries.  Something which we call life lifts matter up, in opposition to gravity, into thousands of living forms.  The tree lifts potash, silica, and lime up one or two hundred feet into the air; it elbows the soil away from its hole where it enters the ground; its roots split rocks.  A giant sequoia lifts tons of solid matter and water up hundreds of feet.  So will an explosion of powder or dynamite, but the tree does it slowly and silently by the organizing power of life.  The vital is as inscrutably identified with the mechanical and chemical as the soul is identified with the body.  They are one while yet they are two.