THE CONQUEST OF NATURE 



held to be inferior to the catapult. The printed book 

 did not instantly make its way against the work of the 

 scribe. Neither did the steam engine immediately sup- 

 plant water power and the direct application of human 

 labor. But in each case the new invention virtually rang 

 the death knell of the old method from the hour of its 

 inauguration, and the end was no less sure because it 

 was delayed. And it requires no great powers of 

 divination to foretell that in the coming age, the electric 

 dynamo driven by water power may take the place of 

 the steam engine. The Age of Steam may pass, with 

 only at most a few generations of domination. And 

 it is within the possibilities that the Age of Electricity 

 will scarcely come into its own before it may be dis- 

 placed by an Age of Radio-Activity. To press that 

 point, however, would be to enter the field of prophecy, 

 which is no part of my present purpose. 



All that I have wished to point out is that for some 

 thousands of years after man learned to make imple- 

 ments of iron, the industrial world and the human 

 civilization that depends upon it, pursued a relatively 

 static course, like a broad, sluggish current, with no new 

 revolutionary discovery to impel it into new channels; 

 and that then one revolutionary discovery succeeded 

 another with bewildering suddenness, so that we of 

 the early days of the twentieth century are farther 

 removed, in an industrial way, from our forerunners 

 of two hundred years ago, than those children of the 

 eighteenth century were from the earliest civilization 

 that ever developed on our globe. Indeed, this startling 

 contrast would still hold true, were we to consider the 



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