In order to render the Logic more easy and more practical, First, the author has omitted the perplexed, undiscussed and indeterminate Greek derivatives, which give vagueness or obscurity to the matter contained in many popular text books of Logic; and he has aimed to use in their stead the most plain and simple terminology. This perpetual multiplication of indefinite and unintelligible technicalities, which are devised as if to embody new forms of thought, helps much to render the study of Logic and Philosophy discouraging, and their very names repulsive, even to the most ambitious and the most intelligent young minds that attempt to master the established elementary principles of these an-important branches of a good education, The introduction of a new term into a book on Philosophy, does not necessarily imply the actual discovery of a new truth. It is a significant fact that, while eccentric thought and novel phraseology possess a peculiar charm for ill-educated, rambling and superficial minds; yet, the language which remains in prevailing use, is the embodiment of deep and true philosophy; and the words as well as the conclusions, which convey what is absurd or preposterous, it must necessarily repudiate, by the genera1law of human thought. It was judged best, also, for the interests of learners in general, to omit the discussion of the modes and figures of the syllogism; for, in practice they are not attended to, even by those who actually argue in form, the simple rules of demonstration sufficing for all practical purposes, and being all that is even really useful in the strictest argumentation. On the other hand, it was deemed expedient to introduce some matters that pertain to branches of Philosophy, whose full treatment is appropriate to another volume; e. g., certain subjects which strictly belong to Psychology, Cosmology and Natural Theology.