ON THE PHYSICAL VIEW OF NATLUK. l-4o 



conlinuinif the worth ul' the tieiisure which lav hidden 

 in the experimental researches of Faraday. Next to the 

 handbook of Thomson and Tait, no writings prohahly 

 have done mr)re — especiall}' outside of England, on the 

 Continent and in America — than those of Maxwell to 

 revolutionise the teaching of natural philosophy. 



I must now revert to what I said in the last chap- 

 ter regarding Maxwell's attempt to ijut the ideas of 32. 

 Faraday on the comnninication of electric and magnetic Maxweii. 

 phenomena through space into mathematical language — 

 i.e., into measurable terms. T there related how Max- 

 well's earliest treatment of the subject was an attempt 

 to construct a mechanical model of the dielectric that 

 would be capable of exhibiting and transmitting the pro- 

 perties of stress — i.e., of tension and pressure — which 

 the experimental researches of Faraday had partly de- 

 monstrated and partly suggested. In the sequel, as 

 was said, he desisted from this attempt, which lias 

 since been taken up and further elaborated by others, 

 and resorted to a different train of reasoning. This 

 line had been suggested by the introduction of the 

 doctrine of energy into all phy.sieal research. As the 

 work of scientific chemists was for a long time ex- 

 clusively governed by the application of the principle 

 of the constancy of weight or conservation of matter, 

 so, when once the mathematical expression of the 

 various forms of energy had been correctly established, 

 it became possible to arrive at a multitude of relations 

 of physical quantities merely by a})plying the ])riiu'ij.le 

 of the constancy of the quantity of energy. In this 

 way the principle of energy is a kind of regulative 

 VOL. IL K 



