The public safety, and the relative interests of states; political establishments, the pretensions of party, commerce, and arts, are subjects which engage the attention of nations. The advantages gained in some of these particulars, determine the degree of national prosperity. The ardour and vigour with which they are at any one time pursued, is the measure of a national spirit. When those objects cease to animate, nations may be said to languish; when they are during a considerable time neglected, states must decline, and their people degenerate. In the most forward, enterprising, inventive, and industrious nations, this spirit is fluctuating; and they who continue longest to gain advantages, or to preserve them, have periods of remissness, as well as of ardour. The desire of public safety, is, at all times, a powerful motive of conduct; but it operates most when combined with occasional passions, when provocations inflame, when successes encourage, or mortifications exasperate. A whole people, like the individuals of whom they are composed, act under the influence of temporary humours, sanguine hopes, or vehement animosities. They are disposed, at one time, to enter on national struggles with vehemence; at another, to drop them from mere lassitude and disgust. In their civil debates and contentions at home, they are occasionally ardent or remiss. Epidemical passions arise or subside on trivial as well as important grounds. Parties are ready, at one time, to take their names and the pretence of their oppositions, from mere caprice or accident; at another time, they suffer the most serious occasions to pass in silence. If a vein of literary genius be casually opened, or a new subject of disquisition be started, real or pretended discoveries suddenly multiply, and every conversation is inquisitive and animated. If a new source of wealth be found, or a prospect of conquest be offered, the imaginations of men are inflamed, and whole quarters of the globe are suddenly engaged in ruinous or in successful adventures. Could we recall the spirit that was exerted, or enter into the views that were entertained, by our ancestors, when they burst, like a deluge, from their ancient seats, and poured into the Roman empire, we should probably, after their first success at least, find a ferment in the minds of men, for which no attempt was too arduous, no difficulties insurmountable.