Thousands of persons believe in lucky and unlucky days, numbers, signs and jewels. Many people regard Friday as an unlucky day--as a bad day to commence a journey, to marry, to make any investment. The only reason given is that Friday is an unlucky day. Starting across the sea on Friday could have no possible effect upon the winds, or waves, or tides, any more than starting on any other day, and the only possible reason for thinking Friday unlucky is the assertion that it is so. So it is thought by many that it is dangerous for thirteen people to dine together. Now, if thirteen is a dangerous number, twenty-six ought to be twice as dangerous, and fifty-two four times as terrible. It is said that one of the thirteen will die in a year. Now, there is no possible relation between the number and the digestion of each, between the number and the individual diseases. If fourteen dine together there is greater probability, if we take into account only the number, of a death within the year, than there would be if only thirteen were at the table. Overturning the salt is very unlucky, but spilling the vinegar makes no difference. Why salt should be revengeful and vinegar forgiving has never been told. If the first person who enters a theatre is crosseyed, the audience will be small and the "run" a failure. How the peculiarity of the eyes of the first one who enters, changes the intention of a community, or how the intentions of a community cause the cross-eyed man to go early, has never been satisfactorily explained. Between this so-called cause and the so-called effect there is, so far as we can see, no possible relation. To wear an opal is bad luck, but rubies bring health. How these stones affect the future, how they destroy causes and defeat effects, no one pretends to know. So, there are thousands of lucky and unlucky tilings, warnings, omens and prophecies, but all sensible, sane and reasoning human beings know that every one is an absurd and idiotic superstition. Let us take another step: For many centuries it was believed that eclipses of the sun and moon were prophetic of pestilence or famine, and that comets foretold the death of kings, or the destruction of nations, the coming of war or plague. All strange appearances in the heavens--the Northern Lights, circles about the moon, sun dogs, falling stars--filled our intelligent ancestors with terror. They fell upon their knees--did their best with sacrifice and prayer to avoid the threatened disaster. Their faces were ashen with fear as they closed their eyes and cried to the heavens for help. The clergy, who were as familiar with God then as the orthodox preachers are now, knew exactly the meaning of eclipses and sun dogs and Northern Lights; knew that God's patience was nearly exhausted; that he was then whetting the sword of his wrath, and that the people could save themselves only by obeying the priests, by counting their beads and doubling their subscriptions.