216 THE KOYAL INSTITUTION OF GREAT BRITAIN. 



'' We lircvc to extend our views over the wliole circle of natural and artificial 

 knowledge, to consider in detail the principles and application of the philosophy 

 of nature and of art. * * To insist on the propriety of a distinct and 

 logical order is unnecessary ; for, however superfluous we may deem the scholastic 

 forms of rhetoric, it is confessedly advantageous to the judgment as well as to 

 the memory to unite those things wiiich are naturally connected, and to separate 

 those which are essentially distinct. When a traveller is desirous of becoming 

 acquainted with a city or country before unknow^l to him, he naturally begins 

 by taking from some elevated situation a distant view of the distrilnition of its 

 parts ; and in the same manner, before we enter on the particular consideration 

 of the subjects of our researches, it may be of use to form to ourselves a general 

 idea of the sciences and arts which are to be placed among them. * * * 

 The division of the whole course of lectures into three parts was originally sug- 

 gested by the periodical succession in which the appointed hours recur ; but it 

 appears to be more convenient than any other for the regular classification of 

 the subjects. The general doctnnes of motion, and their application to all pur- 

 poses variable at pleasure, supply the materials of the first two parts, of which 

 the one treats of the motions of solid bodies, and the other of those of fluids, 

 including the theory of light. The third part relates to the particular history 

 of the phenomena of nature, and of the affections of bodies actually existing in 

 the universe, independently of the art of man ; comprehending astronomy, geog- 

 raphy, and the doctrine of the properties of matterj and of the most general and 

 powerful agents that influence it.* 



" The synthetical order of proceeding, from simple and general principles to 

 their more intricate combinations in particular cases, is b}^ far the most compen- 

 dious for conveying information with regard to sciences that are at all referable 

 to certain fundamental laws. For these laws being once established, each fact, 

 as soon as it is known, assumes its place in the system, and is retained in the 

 memory by its relation to the rest as a connecting link. In the analytical mode, 

 on the contrary, which is absolutely necessary for the first investigation of truth, 

 we are obliged to begin by collecting a number of insulated circumstances, which 

 lead us back by degrees to the knowledge of original principles, bui which, until 

 we arrive at those principles, are merely a burden to the memory. For the phe- 

 nomena of nature resemble the scattered leaves of Sybilline prophecies ; a word 

 only or a single syllable is written on each leaf, which, when separately consid- 

 ered, conveys no instruction to the mind ; but when by the labor of patient investi- 

 gation every fragment is replaced in its appropriate connection, the whole begins 

 at once to speak a perspicuous and harmonious language. * * * 



"Before proceeding to the examination of the several parts of our plan, we 

 must pause to consider the mode of reasoning w'hich is the most generally to be 

 adopted. It depends on the axiom which has always been essentially concerned 

 in every improvement of natural philosophy, but which has been more and more 

 employed, ever since the revival of letters, under the name of induction. That 

 like causes produce like efl'ects, or that in similar circumstances similar conse- 

 quences ensue, is the most general and most important law of nature ; it is the 

 foundation of all analogical reasoning, and is collected from constant experience 

 by an indispensable and unavoidable propensity of the human mind. * * * 

 In the application of induction, the greatest caution and circumspection are neces- 

 sary ; for it is obvious that before we can infer with certainty the complete simi- 

 larity of two events, we must be perfectly well assured that we are acquainted 



* This third part should include, along with the properties of matter and the particular 

 action of its particles, the whole of chemical science: but the varietj' and importance of 

 the researches of chemistry require a separate and minute discussion, and the novelty as well 

 as beauty of many of the experiments with which the labors of our contemporaries have 

 enriched this branch of knowledge, and which Vvill be repeated in the amphitheatre of the 

 Institution by the professor of chemistry, suffices to make this part of natural philosophy the 

 most interesting of all the sciences. 



