4. 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 follows 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; (3.) Explication of Conceptions; (4.) Induction of Laws of Phenomena; (5.) Induction of Causes; (6.) Application of Inductive Discoveries. 5. Of these six processes, the methods by which the second and fourth may be assisted are here our {144} 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 to 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. {{145}} CHAPTER II. OF METHODS OF OBSERVATION. APHORISM XXVIII.