The world is so empty if one thinks only of mountains, rivers and cities; but to know someone who thinks and feels with us, and who, though distant, is close to us in spirit, this makes the earth for us an inhabited garden.

Nature knows no pause in progress and development, and attaches her curse on all inaction.

On all the peaks lies peace.

The assault of our enemies is not part of our life; it is only part of our experience; we throw it off and guard ourselves against it as against frost, storm, rain, hail, or any other of the external evils which may be expected to happen.

Never by reflection, but only by doing is self- knowledge possible to one.

Without my attempts in natural science, I should never have learned to know mankind such as it is. In nothing else can we so closely approach pure contemplation and thought, so closely observe the errors of the senses and of the understanding, the weak and strong points of character.

In comradeship is danger countered best.