666 THE POPULAR SCIENCE MONTHLY. 



I hear people not infrequently express the belief that man will soon 

 exhaust the field of invention. The inventions of the last century have 

 been so numerous and wonderful that to many minds it seems most 

 likely that man will soon reach the limit of his power, or that he will 

 exhaust the resources of Nature. But there is little reason to fear that 

 either condition can be reached for ages, if ever. It is as little likely 

 that man will ever reach the limit of invention as it is that he will be 

 able to fix the bounds of the universe. Man makes inventions by com- 

 bining the materials and forces of Nature, so as to reach new results. 

 Let any one consider how numerous are the materials which Nature 

 presents to the observation and use of man, how varied in kind and 

 degree are the forces w^hich are in constant operation, and how multi- 

 farious and intricate are the laws which govern their actions and re- 

 lations, and then calculate, if he can, the number of possible combi- 

 nations which can be made. I have seen the statement, which is no 

 doubt true, that the fifteen blocks in the gem-puzzle can be arranged 

 in more than a million different ways. If this simple toy possesses 

 such capabilities, what possibility is there that man can ever exhaust 

 the field of Nature ? Wonderful as man's inventions are in number 

 and character, they are at an infinite distance behind the works of 

 Nature. What a multitude of created things there are in Nature, 

 looking simply at species and varieties, and not at the individuals ! 

 How many kinds of plants and animals are to be found ! What mul- 

 titudes of reptiles and insects ! No machine which man has invented 

 calls into play such wonderful forces or is governed by such wonder- 

 ful laws as the humblest plant on which he treads ! Man is far enough 

 yet from inventing a structure which shall build itself up from the 

 earth, air, and water, and scatter germs for its indefinite reduplication ! 

 He has succeeded in copying some of the products of Nature, and he 

 will achieve still greater results, but in doing it he has but opened 

 a new field of invention, one which only a few years before seemed 

 utterly beyond his reach. He has enlarged the field of invention, not 

 exhausted it. A striking instance of what man has done in this new 

 direction is exhibited in the substance called alizarine. It is the sub- 

 stance which gives to madder its coloring quality. Not many years 

 ago, madder was extensively cultivated in many countries to supply 

 the demand for the arts. Now the article is made artificially from 

 coal-tar, and the fields where madder was cultivated have to be 

 devoted to other purposes. Invention has taught man how to make 

 indigo, and the artificial article is likely to supplant the natural prod- 

 uct. Diamonds have been produced artificially. I have full faith that 

 sugar will in time in like manner be produced artificially. Starch and 

 oil may not unlikely be })rovided in the same way. Man now culti- 

 vates the silk-worm which devours mulberry-leaves and converts a 

 large portion into a glutinous fluid which, when spun out into a fine 

 thread, hardens and forms our silk. Man may yet learn how to ex- 



