400 BRAIN WORK AND 



striking, but its explanation is very simple : 

 those men the Watts and the Stephensons 

 knew something which the savants do not know 

 they knew the use of their hands ; their 

 surroundings stimulated their inventive powers ; 

 they knew machines, their leading principles, 

 and their work ; they had breathed the at- 

 mosphere of the workshop and the building- 

 yard. 



We know how men of science will meet the 

 reproach. They will say : " We discover the 

 laws of nature, let others apply them ; it is a 

 simple division of labour." But such a re- 

 joinder would be utterly untrue. The march 

 of progress is quite the reverse, because in a 

 hundred cases against one the mechanical 

 invention comes before the discovery of the 

 scientific law. It was not the dynamical 

 theory of heat which came before the steam- 

 engine it foUowed it. 



When thousands of engines already were 

 transforming heat into motion tinder the eyes 

 of hundreds of professors, and when they had 

 done so for half a century, or more ; when 

 thousands of trains, stopped by powerful brakes, 

 were disengaging heat and spreading sheaves 

 of sparks on the rails at their approach to the 

 stations ; when all over the civilised world 

 heavy hammers and perforators were rendering 



