I do not know what I may appear to the world， but to myself I seem to have been only like a boy playing on the sea-shore， and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary， whilst the great ocean of truth lay all undiscovered before me.
To every action there is always opposed an equal reaction； or， the mutual actions of two bodies upon each other are always equal， and directed to contrary parts.
