我为我所做的感到快乐和自豪，但从未完全满足。

The preservation of the means of knowledge among the lowest ranks is of more importance to the public than all the property of all the rich men in the country.

数学是给不同事物赋予相同名称的艺术。

You think it will never happen to you, that it cannot happen to you, that you are the only person in the world to whom none of these things will ever happen, and then, one by one, they all begin to happen to you, in the same way they happen to everyone else.