The improvements that have been effected in natural philosophy have by degrees convinced the enlightened part of mankind that the material universe is every where subject to laws, fixed in their weight, measure and duration, capable of the most exact calculation, and which in no case admit of variation and exception. Whatever is not thus to be accounted for is of mind, and springs from the volition of some being, of which the material form is subjected to our senses, and the action of which is in like manner regulated by the laws of matter. Beside this, mind, as well as matter, is subject to fixed laws; and thus every phenomenon and occurrence around us is rendered a topic for the speculations of sagacity and foresight. Such is the creed which science has universally prescribed to the judicious and reflecting among us. It was otherwise in the infancy and less mature state of human knowledge. The chain of causes and consequences was yet unrecognized; and events perpetually occurred, for which no sagacity that was then in being was able to assign an original. Hence men felt themselves habitually disposed to refer many of the appearances with which they were conversant to the agency of invisible intelligences; sometimes under the influence of a benignant disposition, sometimes of malice, and sometimes perhaps from an inclination to make themselves sport of the wonder and astonishment of ignorant mortals. Omens and portents told these men of some piece of good or ill fortune speedily to befal them. The flight of birds was watched by them, as foretokening somewhat important. Thunder excited in them a feeling of supernatural terror. Eclipses with fear of change perplexed the nations. The phenomena of the heavens, regular and irregular, were anxiously remarked from the same principle. During the hours of darkness men were apt to see a supernatural being in every bush; and they could not cross a receptacle for the dead, without expecting to encounter some one of the departed uneasily wandering among graves, or commissioned to reveal somewhat momentous and deeply affecting to the survivors. Fairies danced in the moonlight glade; and something preternatural perpetually occurred to fill the living with admiration and awe.