What are called accidental discoveries are almost invariably made by those who are looking for something.

A man incurs about as much risk of being struck by lightning as by accidental luck.

There is, perhaps, an element of luck in the amount of success which crowns the efforts of different men; but even here it will usually be found that the sagacity with which the efforts are directed and the energy with which they are prosecuted measure pretty accurately the luck contained in the results achieved.
Apparent exceptions will be found to relate almost wholly to single undertakings, while in the long run the rule will hold good.

Two pearl-divers, equally expert, dive together and work with equal energy.
One brings up a pearl, while the other returns empty-handed.

But let both persevere and at the end of five, ten or twenty years it will be found that they succeeded almost in exact proportion to their skill and industry.
Lincoln, being asked by an anxious visitor what he would do after three or four years if the rebellion was not subdued, replied: "Oh, there is no alternative but to keep pegging away." "It is in me and it shall come out," said Sheridan, when told that he would never make an orator, as he had failed in his first speech in Parliament.