The more efficient causes of progress seem to consist of a good education during youth whilst the brain is impressible, and of a high standard of excellence, inculcated by the ablest and best men, embodied in the laws, customs and traditions of the nation, and enforced by public opinion.

I never gave up Christianity until I was forty years of age.

Hence, a traveller should be a botanist, for in all views plants form the chief embellishment.

... if variations useful to any organic being do occur, assuredly individuals thus characterized will have the best chance of being perserved in the struggle for life; and from the strong principle of inheritance they will tend to produce offsping similarly characterized. This principle of preservation, I have called, for the sake of brevity, Natural Selection.

[Alexander von Humboldt was the] greatest scientific traveller who ever lived.

...conscience looks backwards and judges past actions, inducing that kind of dissatisfaction, which if weak we call regret, and if severe remorse.

We may confidently come to the conclusion, that the forces which slowly and by little starts uplift continents, and that those which at successive periods pour forth volcanic matter from open orifices, are identical.