IO OF THE USE AND ADVANTAGE

both the revolutions together, should know howto conciliate, and make them agree. It wasthis that gave birth to the Calendar; whichwas for a long time extremely imperfect, hasbeen often reformed, and is still attended withmany embarrassments.

Chronology is another subject so intimatelyconnected with astronomical observations, thatwithout their assistance, we should have beenbut ill acquainted with the events recorded inhistory, and the transactions of past ages. But itis only since certain memorable epochas, thatthis art can be considered as having any solidfoundation. Beyond these every thing is in-volved in darkness and obscurity. That uncer-tain tradition, which, before the invention ofletters, was the only vehicle of information, hasconfounded and disfigured every relation. Wefind in ancient annals but few facts that arefixed by precise dates, and even those few areseldom the same in different authors.

In this perplexed labyrinth, we have no otherguide than what is afforded by the light ofscience. Those facts which are agreeable to thecommon testimony of credible historians, areconsidered as so many fixed points, wherethe weary traveller may rest himself, after histedious researches in the barren regions of an-tiquity. But the observations by which thedates of early events have been determined are

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