The sun might blaze out upon the earth forever without burning a hole in it or setting anything on fire; whereas a very few of these rays concentrated in a burning glass would, as stated, transform a diamond into vapor.
Sir James Mackintosh was a man of marvelous ability.

He excited in everybody who knew him great expectations, but there was no purpose in his life to act as a burning glass to collect the brilliant rays of his intellect, by which he might have dazzled the world.

Most men have ability enough, if they could only focalize it into one grand, central, all-absorbing purpose, to accomplish great things.
"To encourage me in my efforts to cultivate the power of attention," said a friend of John C.Calhoun, "he stated that to this end he had early subjected his mind to such a rigid course of discipline, and had persisted without faltering until he had acquired a perfect control over it; that he could now confine it to any subject as long as he pleased, without wandering even for a moment; that it was his uniform habit, when he set out alone to walk or ride, to select a subject for reflection, and that he never suffered his attention to wander from it until he was satisfied with its examination." "My friend laughs at me because I have but one idea," said a learned American chemist; "but I have learned that if I wish ever to make a breach in a wall, I must play my guns continually upon one point." "It is his will that has made him what he is," said an intimate friend of Philip D.Armour, the Chicago millionaire.

"He fixes his eye on something ahead, and no matter what rises upon the right or the left he never sees it.

He goes straight in pursuit of the object ahead, and overtakes it at last.