To you I would apologize for the liberties I have taken with your Theory, and your publications in relation to it, which have made their appearance in the newspapers of the day. When I commenced this compilation, in support of your doctrine of Concentric Spheres, I had no view to its publication. I had collected all the papers on the subject, upon which I could lay my hands, with the intention of investigating the Theory for my own satisfaction: but the scattered and irregular order in which I found them, and in which they must necessarily appear in detached Newspaper essays, published at different and distant times, induced me to attempt a methodical arrangement, for the purpose of facilitating my own enquiries. When I had completed this, the same reasons, added to the consideration, that you have not only invited, but solicited the investigation of your theory, declaring it "as free as air," to every person, to make such use of it as he may think proper, influenced me to conclude on publishing the result of my investigations. Having come to this determination, I have added a Preface, an Introductory chapter, and a few things in conclusion, to make it look more like a Book. As I have not seen all your publications in the newspapers, if I have not fully understood, or if I have misrepresented your theory in any particular, I assure you it has been done unintentionally――it has arisen entirely from my want of adequate information; and I hope you will, in the spirit of candour and good nature, pardon and correct any errors into which I may have fallen. Had an opportunity offered, and could I have done it with propriety, I should certainly have submitted the manuscript to your revision, previous to its publication. However, as this sketch is only intended to elicit further investigation, and can only live until a formal and systematic treatise shall appear from your pen, I hope you will permit it to pass as the Pioneer to a more complete demonstration of your Theory of Concentric Spheres. I AM SIR, _One of the believers in that Theory_,―― THE AUTHOR. 1824. CONTENTS. CHAPTER I. Containing an introductory glance at some of the different Theories and Opinions which have been embraced respecting the formation of the Earth, and the reception which those Theories met with from the world when first promulgated. CHAPTER II. Symmes's Theory; comprehending his description of the form of the earth, and of the other orbs in the Universe; his principles of gravity, and the points wherein he differs from the old or generally received theories. CHAPTER III. Symmes's Theory supported by arguments drawn from the principles inherent in matter, and the consequences resulting from motion; tending to show that, from necessity, matter must form itself into concentric circles or spheres, such as Symmes describes the earth to be composed of. CHAPTER IV. Arguments in support of Symmes's Theory, drawn from Celestial appearances. CHAPTER V.