Attention, if sudden and close, graduates into surprise; and this into astonishment; and this into stupefied amazement.

Every one must be struck with astonishment, when he first beholds one of these vast rings of coral-rock, often many leagues in diameter, here and there surmounted by a low verdant island with dazzling white shores, bathed on the outside by the foaming breakers of the ocean, and on the inside surrounding a calm expanse of water, which, from reflection, is of a bright but pale green color.

We are not here concerned with hopes or fears, only with truth as far as our reason permits us to discover it.

I have deeply regretted that I did not proceed far enough at least to understand something of the great leading principles of mathematics, for men thus endowed seem to have an extra sense.

Free will is to mind what chance is to matter.

I am a firm believer, that without speculation there is no good and original observation.

On seeing the marsupials in Australia for the first time and comparing them to placental mammals: “An unbeliever . . . might exclaim 'Surely two distinct Creators must have been at work'”