proposed for that purpose methods from which he promised a better success. (p. 3.) The Methods by which the construction of Science is promoted are, Methods of Observation, Methods of obtaining clear Ideas, and Methods of Induction. Aphorism xxvii. I shall, therefore, attempt to resolve the Process of Discovery into its parts, and to give an account as distinct as may be of Rules and Methods which belong to each portion of the process. In Book II. we considered the three main parts of the process by which science is constructed namely, the Decomposition and Observation of Complex Facts; the Explication of our Ideal Conceptions; and the Colligation of Elementary Facts by means of those conceptions. The first and last of these three steps are capable of receiving additional accuracy by peculiar processes. They may further the advance of science in a more effectual manner, when directed by special technical Methods, of which in the present book we must give a brief view. In this more technical form, the observation of facts involves the Measurement of Phenomena; and the Colligation of Facts includes all arts and rules by which the process of Induction can be assisted. Hence we shall have here to consider Methods of Observation, and Methods of Induction, using these phrases in the widest sense. The second of the three steps above mentioned, the Explication of our Conceptions, does not admit of being much, assisted by methods, although something may be done by Education and Dis cussion. The Methods of Induction, of which we have to speak, apply only to the first step in our ascent from phenomena to laws of Nature ;-the discovery of Laws of Phenomena. A higher and ulterior step remains behind, and follow in natural order the discovery of Laws of Phenomena; namely, the Discovery of Causes; and this must be stated as a distinct and essential process in a complete view of the course of science. Again, when we have thus ascended to the causes of phenomena and of their laws, we can often reason downwards from the cause so discovered ; and we are thus led to suggestions of new phenomena, or to new explanations of phenomena already known. Such proceedings may be termed Applications of our discoveries; including in the phrase, Verifications of our Doctrines by such an application of them to observed facts. Hence we have the following series of processes concerned in the formation of science. (1.) Decomposition of Facts; (2.) Measurement of Phenomena; 4.) Induction of Laws of Phenomena; (6.) Application of Inductive Discoveries. Of these six processes, the methods by which the second and fourth may be assisted are here our peculiar object of attention. The treatment of these subjects in the present work must necessarily be scanty and imperfect, although we may perhaps be able to add something to what has hitherto been systematically taught on these heads. Methods of Observation and of Induction might of themselves form an abundant subject for a treatise, and hereafter probably will do so, in the hands of future writers. A few remarks, offered as contributions on this subject, may serve to show how extensive it is, and how much more ready it now is than it ever before was, for a systematic discussion. Of the above steps of the formation of science, the first, the Decomposition of Facts, has already been sufficiently explained in the last Book for if we pursue it into further detail and exactitude, we find that we gradually trench upon some of the succeeding parts. I, therefore, proceed to treat of the second step, the Measurement of Phenomena;—of Methods by which this work, in its widest sense, is executed, and these I shall term Methods of Observation. 7. From Bowen's Logic, ed. 1874, pp. 30-38. Logic is the Science of the Necessary Laws of Pure Thought, that is, it treats of Language so far only as this is the vehicle of Thought. Just the reverse is true of the science of Grammar, which treats primarily of Language, and only secondarily of Thought. Logic might be called the Grammar of Thought. It Pure, or, as it is sometimes termed, Formal Thought, is the mere process of thinking, irrespective of what we are thinking about. has already been said that the Acquisitive or Perceptive Faculty furnishes "the Matter," while the Understanding supplies "the Form," of our knowledge. This distinction between Matter and Form is one of considerable importance in the history of philosophy. The former is the crude material or the stuff of which anything. consists, or out of which it is made; while the latter is the peculiar shape or modification given to it by the artist, whereby it has become this particular thing which it is, and not something else which might have been fashioned out of the same substance. Thus, wood is the Matter of the desk on which I am writing, whilst the Form is that which entitles it to be called a desk, rather than a table or a chair. Vocal sound is the Matter of speech, and articulation is its Form. It is evident that these are two correlative notions, each of which implies the other: Matter cannot exist except under some Form, and there cannot be any Form except of some given Mat ter. But though the two cannot actually be separated, the mind can consider each separately through that process, called abstraction, whereby the attention is wholly given to the one to the exclusion of the other. We may think separately of the attributes which are common to a whole class of Forms, disregarding altogether, for the moment, the Matter of which each of them really consists. Borrowing algebraic symbols, the Matter in each case may be designated by a letter of the alphabet, the peculiar significance of which is, that it stands for any Matter whatever, and not for any one in particular. Thus, A is B, is the Form of an affirma tive judgment, wherein A and B stand for any two Concepts whatever. Hence, whatever is true of the general formula, A is B, will be true also of any such particular instances, as Iron is malleable, Trees are plants, etc., wherein the Form is associated with some particular Matter. In saying, then, that Logic is concerned only with the Forms of Thought, or Pure Thought, or Thought in the abstract,for all these expressions signify the same thing,-we mean only, that what is Material in Thought is extralogical, and, as logicians, we have nothing to do with it; just as the geometer has nothing to do with the particular diagram on the paper before him, except so far as it is a symbol, or universal Form, of all possible figures of the same general character. . Again, the definition of Logic assumes that the process of Thinking, like every other operation in nature, does not take place at random, but according to certain fixed Laws or invariable modes of procedure. There could be no communication of Thought from one mind to another, if the process of Thinking in all minds were not subject to the same general rules. We follow these laws for the most part unconsciously, as a distinct recognition of them is not by any means necessary for correct thinking; just so, many persons speak and write correctly without any knowledge of the grammarian's rules. Properly speaking, Pure Logic terminates. with the consideration of the three classes of products-namely, Concepts, Judgments, and |