PHYSICAL SCIENCE. 9 



spoken of ultimate ratios in mathematics as the 'ghosts of 

 departed quantities.' With like reason we might call the 

 unity of some of our recent philosophers the f ghost of 

 departed pluralities;' having this quality of ghosthood, 

 moreover, that there is nothing truly tangible or sub- 

 stantial about it. 



We have dwelt thus much on these preliminary topics 

 because, while they indicate what may be considered the 

 exaggerations and excesses of theory, they show at the same 

 time that spirit and propensity of modern science of which 

 we have before spoken ; and which, duly regarded^ has been 

 the source of all its high attainments. We now proceed to 

 such details as may best illustrate this spirit in its application 

 to different branches of science ; selecting, amidst the multi- 

 tude of examples, those especially which involve either some 

 new physical principle or some new method of physical 

 enquiry. It has been said by one who could well estimate 

 the value of the latter, c La connoissance de la methode qui 

 a guide 1'homme de genie, n'est pas moins utile au progres de 

 la science que ses decouvertes.' A new method is often 

 indeed in itself the greatest discovery, and betokening the 

 highest genius in him to whom it is due. 



In dealing with this wide subject, the first and most 

 material division is that between the Forces acting on or in 

 Matter ; and the various forms of Matter ; inorganic or organic, 

 so acted upon. With full admission of the difficulty of 

 defining the abstract nature of matter and force, and their 

 mutual relations in the universe, this distinction is still the 

 only one which our intelligence can apprehend or practically 

 apply to the objective phenomena ever present and active 

 around us. 



In regard to matter and force it may undoubtedly be 

 affirmed that all questions as to their nature become more 



