Inaction saps the vigor of the mind.

Weight is caused by one element being situated in another; and it moves by the shortest line towards its centre, not by its own choice, not because the centre draws it to itself, but because the other intervening element cannot withstand it.

The eye is the window of the human body through which it feels its way and enjoys the beauty of the world.

If we make mistakes in our first compositions and do not know them, we may not amend them.

I love those who can smile in trouble, who can gather strength from distress, and grow brave by reflection. 'Tis the business of little minds to shrink, but they whose heart is firm, and whose conscience approves their conduct, will pursue their principles unto death.

It is easier to contend with evil at the first than at the last.

Instrumental or mechanical science is the noblest and above all others, the most useful.