Almost everybody is now willing to admit this method of reckoning probability when it is applied to dawns or to life insurance. It seems quite natural to say that we know the sun will rise again because, so far as we know, it always has risen; or to say that a baby has a longer prospect of life than has a very old man because we have observed that babies generally live, while very old men generally die. But when we apply the same method to the calculations of certain other things--the behavior of our penny, for instance--we shall meet, strangely enough, with a lot of heretics. If a penny has fallen heads for twenty times in succession, there are those who will say that the chances of heads coming on the next throw are much worse than one to one. “It is time for a change,” they will contend. And nothing can keep them, if sportingly inclined, from wagering their money on tails. But a mathematician will coldly bet on heads. _He knows that there is something the matter with that penny!_ So come what are known as “runs of luck,”--a subject apparently remote from that of free will, but not so remote as it seems. Runs of luck are the result of unknown influences; for if the influences are known we do not say “luck,” we use a harsher term. The oftener a thing has happened before, the more likely it is to happen again. Some large force must be at work, or there would not have been the run. This is such an important rule that anyone who doubts it would do well to convince himself of its validity. He will in that way not only improve his mind, he will save money be he never so little of a “gambler” in the vicious sense of the term. Losers are always playing the stock-market and the world for “reactions” that “must come.” Winners always “go with the trend.” They are vicious only when their prizes are evil. “But what,” some will say, “of the change of luck which wipes out the winnings? What of those larger cycles which bring the smaller cycles to an end?” Just this. We know nothing of the larger cycles until we, or somebody whose word we can trust, has begun to experience them. Therefore our ignorance is complete in most cases, and we have no chance against the larger cycles or rhythms at all--which is why sensible people usually keep out of the stock-market. Doubtless there is some larger cycle in cosmic events which will some day put out the sun. But unless we have somehow been able to put our finger already upon its pulse, we must ignore it in our calculations. We cannot bring it to book. When any one cycle has kept up a faithful performance as long as the sun has kept on rising, it must be a rather large cycle and is pretty safe to depend on for our remaining days.