The most common is an error in arithmetic which the little I have above said on the calculus of chance should be enough to correct. It is putting faith in their good luck, or falling into discouragement from their bad luck. Each is equally silly. A sequence of any kind of luck does not offer the slightest presumption that it will continue. The chances remain precisely as at the beginning, and are about six to one against the continuance of either extreme in the same individual. In matters of pure chance no sustained coincidence in either direction adds the least probability to its continuance. This is what is so difficult for men to believe; and so it comes about that faith in good luck is the source of most bad luck. A “run of good luck” has wrecked the lives of more men than has the repetition of disasters. The reason for this is easily shown. The general rule in life is that a man’s prosperity is conditioned closely by the amount and kind of his knowledge, and his skill in the use of it. But the man who “trusts to luck” distinctly renounces the advantages of knowledge, and builds his hopes on his acknowledged impotence to influence the results. He abandons himself to the current of events, and makes no effort to look forward and see whether it will suck him into a whirlpool, or land him on some sunny shore. Scarcely any state of mind could be fraught with greater peril to his future. We have the sayings, “dumb luck” and “a fool for luck;” and the Italians their proverb that one must have a little of the fool in him, _un poco di matto_, to be lucky. Most men are fools, so it is inherently probable that the lucky man will belong to the majority; but beyond that, _his_ folly is conspicuous who bases his hopes of fortune rather on luck than on labor and forethought. The immorality of gambling and its ruinous influence on the happiness of life lie in the fact that it disclaims as useless every precept which prudence, skill, and knowledge lay down as essential to individual success.