Chapter I. Knowledge may be acquired by Astronomy to a certain Extent（续 4）

would have instituted any propitiations, remedies, and preservatives against. the influence of the Ambient, whether present or approaching, general or particular. But, by

| Chap. TIT.) PTOLEMY’S TETRABIBLOS. | 19

means of the science called by them Medical Mathematics, they combined with the power of prognostication the concurrent secondary influence arising out of the institutions and courses of nature, as well as the contfary influence which might be procured out of nature’s variety; and by means of these they rendered the indicated ‘agency useful and advantageous: since their astronomy pointed out to them the kind of temperament hiable to be acted upon, as well as the events about to proceed from the Ambient, and the peculiar influence of those events, while thei? medical skill made them acquainted with every thing suitable or unsuitable to each of the effects to be produced. And it is by this process that remedies for present and preservatives against future disorders are to be acquired ; for, without astronomical knowledge, medical aid would be most frequently unavailing ; since the same identical remedies are not better calculated for all persons whatsoever, than they are for all diseases whatsoever *. | . The practicability and utility of prescience having been thus far briefly explained, the ensuing discourse must be proceeded with. It commences, introductorily, with an ~ account of the efficient properties of each of the heavenly bodies, taken from the rules of the antients, whose observations were founded in nature.—And, first, of the influences of the planets and of the Sun and Moon.