Produced by Marc D'Hooghe at Free Literature GROUNDS OF NATURAL PHILOSOPHY DIVIDED INTO THIRTEEN PARTS WITH AN APPENDIX CONTAINING FIVE PARTS The Second Edition, much altered from the First, which went under the Name of PHILOSOPHICAL AND PHYSICAL OPINIONS Written by the Thrice Noble, Illustrious, and Excellent Princess, THE DUCHESS of NEWCASTLE LONDON, Printed by A. Maxwell, in the Year 1668. To all the UNIVERSITIES IN EUROPE. Most Learned Societies, All Books, without exception, being undoubtedly under your Iurisdiction, it is very strange that some Authors of good note, are not asham'd to repine at it; and the more forward they are in judging others, the less liberty they will allow to be judg'd themselves. But, if there was not a necessity, yet I would make it my choice, To submit, willingly, to your Censures, these _Grounds of Natural Philosophy_, in hopes that you will not condemn them, because they want _Art_, if they be found fraught with Sense and Reason. You are the _Starrs of the First Magnitude_, whose Influence governs the _World of Learning_; and it is my confidence, That you will be propitious to the Birth of this beloved Child of my Brain, whom I take the boldness to recommend to your Patronage; and as, if you vouchsafe to look on it favourably, I shall be extreamly obliged to your Goodness, for its everlasting Life: So, if you resolve to Frown upon it, I beg the favour, That it be not buried in the hard and Rocky Grave of your Displeasure; but be suffer'd, by your gentle silence, to lye still in the soft and easie Bed of Oblivion, which is incomparably the less Punishment of the Two. It is so commonly the error of indulgent Parents, to spoil their Children out of Fondness, that I may be forgiven for spoiling This, in never putting it to suck at the Breast of some Learned Nurse, whom I might have got from among your Students, to have assisted me; but would, obstinately, suckle it my self, and bring it up alone, without the help of any Scholar: Which having caused in the First Edition, (which was published under the name of _Philosophical and Physical Opinions_) many Imperfections; I have endeavoured in this Second, by many Alterations and Additions, (which have forc'd me to give it another Name) to correct them; whereby, I fear, my Faults are rather _changed_ and _encreased_, than _amended_. If you expect fair Proportions in the Parts, and a Beautiful Symmetry in the Whole, having never been taught at all, and having read but little; I acknowledg my self too illiterate to afford it, and too impatient to labour much for Method. But, if you will be contented with _pure Wit_, and the Effects of _meer Contemplation_; I hope, that somewhat of that kind may be found in this Book, and in my other _Philosophical, Poetical_, and _Oratorical Works_: All which I leave, and this especially, to your kind Protection, and am, Your most humble Servant, and Admirer, MARGARET NEWCASTLE. A TABLE of the CONTENTS.