All that comes above the surface [of the globe] lies within the province of Geography; all that comes below that surface lies inside the realm of Geology. The surface of the earth is that which, so to speak, divides them and at the same time 'binds them together in indissoluble union.' We may, perhaps, put the case metaphorically. The relationships of the two are rather like that of man and wife. Geography, like a prudent woman, has followed the sage advice of Shakespeare and taken unto her 'an elder than herself; but she does not trespass on the domain of her consort, nor could she possibly maintain the respect of her children were she to flaunt before the world the assertion that she is 'a woman with a past.'

If we are ever in doubt about what to do, it is a good rule to ask ourselves what we shall wish on the morrow that we had done.

It is easy for men to give advice, but difficult for one's self to follow; we have an example in physicians: for their patients they order a strict regime, for themselves, on going to bed, they do all that they have forbidden to others.

It pays to be obvious, especially if you have a reputation for subtlety.

Stay in college, get the knowledge. And stay there until you're through. If they can make penicillin out of moldy bread, they can sure make something out of you.
Advice to a young person to continue his education.

The reproduction of mankind is a great marvel and mystery. Had God consulted me in the matter, I should have advised him to continue the generation of the species by fashioning them of clay.

The whole value of solitude depends upon one's self; it may be a sanctuary or a prison, a haven of repose or a place of punishment, a heaven or a hell, as we ourselves make it.

When the last Puritan has disappeared from the earth, the man of science will take his place as a killjoy, and we shall be given the same old advice but for different reasons.

Your character will be what you yourself choose to make it.