Ignorance of inductive philosophy has given rise to many superstitions. By the means of inductive philosophy, we are enabled to trace effects to their true causes. For example: Lights have frequently been seen dancing over marshy grounds, near tan-yards, and burying-places, and along the sea shore. Credulous people have believed them to be the spirits of the uneasy dead. This belief must be considered superstitious, not having any foundation on rational evidence. Philosophy teaches that these lights are occasioned by an inflammable gas, which arises from decayed animal and vegetable substances, and takes fire on coming in contact with atmospheric air. Thus we may trace all effects to their true causes. Many persons have supposed that pork killed in the increase of the moon would swell in boiling, while that killed in her wane would shrink. This opinion probably originated in the following manner: Some person killed, at different periods of the moon, two hogs which had been born and fattened together. That killed in her increase swelled in boiling; while the other, killed in her wane, shrunk. He could conceive of no way to account for the facts but on the supposition of lunar influence. This conclusion was accordingly adopted, and at length became an established truth. Yet there was no philosophy in forming this opinion from a few such facts. More experiments should have been tried; and they results would have shown that the real cause of the swelling and shrinking existed in the constitution of the animals. It would have been discovered that pork of fine and solid texture would commonly swell, whenever killed; while that of loose and coarse grain would as generally shrink. And the person would no more have thought of attributing the difference in his pork to the moon than to the spirit of Bonaparte. Let this philosophic principle be applied to this whole class of superstitions, and we shall arrive at similar results. There is the supposed influence of the moon on making soap, grafting trees, cutting timber, and also upon the fortunes of love-sick swains and maidens. The latter are directed to go out in the evening and stand over the bars of a gate, and, looking on the moon, repeat the following lines:-- "All hail to the moon! all hail to thee! I pray thee, good moon, reveal to me, This night, who my husband shall be." They must then go directly to bed, and will dream of their future husband. Upon trial of the experiment, they will probably be inclined to consider it a dreamy notion altogether; for love is of too serious a nature to be fed upon mere _moonshine_. CHAPTER III. IGNORANCE OF THE CAUSES OF DREAMS.