PREFACE. 9 



mediable waste of life, of labour, of capital, of raw 

 material, of soil, of manure, of every bounty which God 

 has bestowed on man, till, as in the eastern Mediter- 

 ranean, whole countries, some of the finest in the world, 

 seem ruined for ever : and all because men will not learn 

 nor obey those physical laws of the universe, which 

 (whether we be conscious of them or not) are all around 

 us, like walls of iron and of adamant say rather, like 

 some vast machine, ruthless though beneficent, among 

 the wheels of which if we entangle ourselves in our rash 

 ignorance, they will not stop to set us free, but crush 

 us, as they have crushed whole nations and whole races 

 ere now, to powder. Very terrible, though very calm, 

 is outraged Nature. 



Though the mills of God grind slowly, 

 Yet they grind exceeding small; 



Though He sit, and wait with patience, 

 With exactness grinds He all. 



It is, I believe, one of the most hopeful among the 

 many hopeful signs of the times, that the civilised 

 nations of Europe and America are awakening slowly 

 but surely to this truth. The civilised world is learning, 

 thank God, more and more of the importance of physical 

 science; year by year, thank God, it is learning to live 

 more and more according to those laws of physical 

 science, which are, as the great Lord Bacon said of old, 

 none other than "Vox Dei in rebus revelata" the 

 Word of God revealed in facts ; and it is gaining by so 

 doing, year by year, more and more of health and 

 wealth ; of peaceful and comfortable, even of graceful 

 and elevating, means of life for fresh millions. 



If you want to know what the study of physical 



