It is a mortifying truth, and ...

It is a mortifying truth, and ought to teach the wisest of us humility, that many of the most valuable discoveries have been the result of chance rather than of contemplation, and of accident rather than of design.
It is a mortifying truth, and ought to teach the wisest of us humility, that many of the most valuable discoveries have been the result of chance rather than of contemplation, and of accident rather than of design.

Quotes from the same author

True friendship is like sound health; the value of it is seldom known until it is lost.
Man, if he compare himself with all that he can see, is at the zenith of power; but if he compare himself with all that he can conceive, he is at the nadir of weakness.
An Irish man fights before he reasons, a Scotchman reasons before he fights, an Englishman is not particular as to the order of precedence, but will do either to accommodate his customers.
In great cities men are more callous both to the happiness and the misery of others, than in the country; for they are constantly in the habit of seeing both extremes.
Men will wrangle for religion, write for it, fight for it, die for it; anything but live for it.