Man is never surprised at those effects, of which he thinks he knows the cause; he believes he does know the cause, as soon as he sees them act in an uniform and determinate manner, or when the motion excited is simple: the descent of a stone, that falls by its own peculiar weight, is an object of contemplation to the philosopher only; to whom the mode by which the most immediate causes act, and the most simple motion, are no less impenetrable mysteries than the most complex motion, and the manner by which the most complicated causes give impulse. The uninformed are seldom tempted either to examine the effects which are familiar to them, or to recur to first principles. They think they see nothing in the descent of a stone, which ought to elicit their surprise, or become the object of their research: it requires a NEWTON to feel that the descent of heavy bodies is a phenomenon, worthy his whole, his most serious attention; it requires the sagacity of a profound experimental philosopher, to discover the laws by which heavy bodies fall, by which they communicate to others their peculiar motion. In short, the mind that is most practised in philosophical observation, has frequently the chagrin to find, that the most simple and most common effects escape all his researches, and remain inexplicable to him. When any extraordinary, any unusual, effect is produced, to which our eyes have not been accustomed; or when we are ignorant of the energies of the cause, the action of which so forcibly strikes our senses, we are tempted to meditate upon it, and take it into our consideration. The European, accustomed to the use of GUNPOWDER, passes it by, without thinking much of its extraordinary energies; the workman, who labours to manufacture it, finds nothing marvellous in its properties, because he daily handles the matter that forms its composition. The American, to whom this powder was a stranger, who had never beheld its operation, looked upon it as a divine power, and its energies as supernatural. The uninformed, who are ignorant of the true cause of THUNDER, contemplate it as the instrument of divine vengeance. The experimental philosopher considers it as the effect of the electric matter, which, nevertheless, is itself a cause which he is very far from perfectly understanding.--It required the keen, the penetrating mind of a FRANKLIN, to throw light on the nature of this subtle fluid--to develop the means by which its effects might be rendered harmless--to turn to useful purposes, a phenomenon that made the ignorant tremble--that filled their minds with terror, their hearts with dismay, as indicating the anger of the gods: impressed with this idea, they prostrated themselves, they sacrificed to JUPITER, to deprecate his wrath.