Nothing is worth more than this day. You cannot relive yesterday. Tomorrow is still beyond your reach.

The world is so great and rich, and life so full of variety, that you can never lack occasions for poems.

If we meet someone who owes us a debt of gratitude, we remember the fact at once. How often we can meet someone to whom we owe a debt of gratitude without thinking about it at all!

All intelligent thoughts have already been thought; what is necessary is only to try to think them again.

Pain and pleasure, good and evil, come to us from unexpected sources. It is not there where we have gathered up our brightest hopes, that the dawn of happiness breaks. It is not there where we have glanced our eye with affright, that we find the deadliest gloom. What should this teach us? To bow to the great and only Source of light, and live humbly and with confiding resignation.

Art is a mediator of the unspeakable.

The works of Lavoisier and his associates operated upon many of us at that time like the Sun's rising after a night of moonshine: but Chemistry is now betrothed to the Mathematics, and is in consequence grown somewhat shy of her former admirers.