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INTRODUCTION.

works, before we inquire into their make, strike us withthe most lively ideas of beauty and magnificence.

3. But if there be so strong a pasiion in contemplativeminds for natural philosophy; all such must certainly receive aparticular pleasure in being informed of Sir Isaac Newton’sdiscoveries,- who alone' has been able to make any great-advancements in the true course leading to natural know-ledge : whereas this important subject had before been u-sually attempted- with that negligence, as cannot .be re-flected on without surprize. Excepting a very sew, who, bypursuing a more rational method, had gained a little trueknowledge in some particular parts of nature; the writers inthis science had generally treated of it after such a manner, asif they thought, that no degree of certainty was ever to be ho-ped for. The custom was to frame conjectures; and if uponcomparing them with things, there appeared some kind of a-greement, though very imperfect, it was held sofficient. Yetat the fame time nothing less was undertaken than intire sy-stems, and fathoming at once the greatest depths of nature ;as if the secret causes of natural effects, contrived and framedby infinite wisdom, could be searched out by the slightestendeavours of our weak understandings. Whereas the onlymethod, that can afford us any prospect of success in thisdifficult work, is to make our enquiries with the utmostcaution, and by very flow degrees. And after our most dili-gent labour, the greatest part of nature will, no doubt, for e-ver remain beyond our reach.

4. This