GROVES CORRELATION OP PHYSICAL FORCES. 401 



the memory of the student of human thought, as one of the documents which 

 serve for the construction of the history of science. 



It is not by discoveries only, and the registration of them by learned 

 societies, that science is advanced. The true seat of science is not in the 

 volume of Transactions, but in the living mind, and the advancement of science 

 consists in the direction of men's minds into a scientific channel ; whether this 

 is done by the announcement of a discovery, the assertion of a paradox, the 

 invention of a scientific phrase, or the exposition of a system of doctrine. It 

 is for the historian of science to determine the magnitude and direction of the 

 impulse communicated by either of these means to human thought. 



But what we require at any given epoch for the advancement of science 

 is not merely to set men thinking, but to produce a concentration of thought 

 in that part of the field of science which at that particular season ought to be 

 cultivated. In the history of science we find that effects of this kind have often 

 been produced by suggestive books, which put into a definite, intelligible, and 

 communicable form, the guiding ideas that are already working in the minds 

 of men of science, so as to lead them to discoveries, but which they cannot yet 

 shape into a definite statement. 



In the first half of the present century, when what is now called the 

 principle of the conservation of energy was as yet unknown by name, it "flung 

 its vague shadow back from the depths of futurity," and those who had greater 

 or less understanding of the times sketched out with greater or less clearness 

 their view of the form into which science was shaping itself. 



Some of these addressed themselves to the advanced cultivators of science, 

 speaking, of course, in learned phraseology ; but others appealed to a larger 

 audience, and spoke in language which they could understand. Mrs Somerville's 

 book on the "Connection of the Physical Sciences" was published in 1834, and 

 had reached its eighth edition in 1849. This fact is enough to shew that there 

 already existed a widespread desire to be able to form some notion of physical 

 science as a whole. 



But when we examine her book in order to find out the nature of the 

 connexion of the physical sciences, we are at first tempted to suppose that it is 

 due to the art of the bookbinder, who has bound into one volume such a quantity 

 of information about each of them. What we find, in fact, is a series of expo- 

 sitions of different sciences, but hardly a word about their connexion. The little 

 that is said about this connexion has reference to the mutual dependence of 



VOL. II. 51 



