preceding instance, the comet was followed, though at a longer interval, by a remarkable paleness of the sun. The _sixth_ return, in the year eleven hundred and six, is recorded by the chronicles of Europe and China: and in the first fervor of the crusades, the Christians and the Mahometans might surmise, with equal reason, that it portended the destruction of the Infidels. The _seventh_ phenomenon, of one thousand six hundred and eighty, was presented to the eyes of an enlightened age. The philosophy of Bayle dispelled a prejudice which Milton's muse had so recently adorned, that the comet, "from its horrid hair shakes pestilence and war." Its road in the heavens was observed with exquisite skill by Flamstead and Cassini: and the mathematical science of Bernoulli, Newton, and Halley, investigated the laws of its revolutions. At the _eighth_ period, in the year two thousand three hundred and fifty-five, their calculations may perhaps be verified by the astronomers of some future capital in the Siberian or American wilderness. II. The near approach of a comet may injure or destroy the globe which we inhabit; but the changes on its surface have been hitherto produced by the action of volcanoes and earthquakes. The nature of the soil may indicate the countries most exposed to these formidable concussions, since they are caused by subterraneous fires, and such fires are kindled by the union and fermentation of iron and sulphur. But their times and effects appear to lie beyond the reach of human curiosity; and the philosopher will discreetly abstain from the prediction of earthquakes, till he has counted the drops of water that silently filtrate on the inflammable mineral, and measured the caverns which increase by resistance the explosion of the imprisoned air. Without assigning the cause, history will distinguish the periods in which these calamitous events have been rare or frequent, and will observe, that this fever of the earth raged with uncommon violence during the reign of Justinian. Each year is marked by the repetition of earthquakes, of such duration, that Constantinople has been shaken above forty days; of such extent, that the shock has been communicated to the whole surface of the globe, or at least of the Roman empire. An impulsive or vibratory motion was felt: enormous chasms were opened, huge and heavy bodies were discharged into the air, the sea alternately advanced and retreated beyond its ordinary bounds, and a mountain was torn from Libanus, and cast into the waves, where it protected, as a mole, the new harbor of Botrys in Phnicia. The stroke that agitates an ant-hill may crush the insect-myriads in the dust; yet truth must extort confession that man has industriously labored for his own destruction. The institution of great cities, which include a nation within the limits of a wall, almost realizes the wish of Caligula, that the Roman people had but one neck.