PREFACE To THE SECOND EDITION. The reception of the following work has been such as to exceed what the author dared to promise himself. Its principles and reasoning have obtained the attention of the public to a considerable extent. This circumstance he has construed as imposing upon him the duty of a severe and assiduous revisal. Every author figures to himself, while writing, a numerous and liberal attention to his lucubrations: if he did not believe that he had something to offer that was worthy of public notice, it is impossible that he should write with any degree of animation. But the most ardent imagination can scarcely be expected to come in competition with sense. In the present instance, there are many things that now appear to the author upon a review, not to have been mediated with a sufficiently profound reflection, and to have been too hastily obtruded upon the reader. These things have been pruned away with a li...