The sale of the first edition of nearly two thou sand copies in the space of three or four months, without being advertised in any form, has encour aged me to believe that the work meets an act ual want, and will be serviceable to the cause of Truth. In the preparation of the present edition, therefore, I have made considerable additions; and, I trust, improvements also, in the hope of making it more worthy and more useful. Two chapters and two sections entire have been ad ded, and chapters three, four and six, have been greatly enlarged, and the argument illus trated and fortified by new facts and authorities.