to which the world of today bears witness. This 

 view is recognized in the plan of our proceed- 

 ings by providing for each great department of 

 knowledge a review of its progress during the 

 century that has elapsed since the great event com- 

 memorated by the scenes outside this hall. But such 

 reviews do not make up that general survey of science 

 at large which is necessary to the development of our 

 theme, and which must include the action of causes that 

 had their origin long before our time. The movement 

 which culminated in making the nineteenth century 

 ever memorable in history is the outcome of a long 

 series of causes, acting through many centuries, which 

 are worthy of especial attention on such an occasion as 

 this. In setting them forth we should avoid laying 

 stress on those visible manifestations which, striking 

 the eye of every beholder, are in no danger of being 

 overlooked, and search rather for those agencies whose 

 activities underlie the whole visible scene, but which 

 are liable to be blotted out of sight by the very brilliancy 

 of the results to which they have given rise. It is easy 

 to draw attention to the wonderful qualities of the oak ; 

 but, from that very fact, it may be needful to point out 

 that the real wonder lies concealed in the acorn from 

 which it grew. 



Our inquiry into the logical order of the causes 

 which have made our civilization what it is today will 

 be facilitated by bringing' to mind certain elementary 

 considerations ideas so familiar that setting them forth 

 may seem like citing a body of truisms and yet so 

 frequently overlooked, not only individually, but in 

 their relation to each other, that the conclusion to 



4 



