June 3, 1904.] 



SCIENCE. 



843 



suits of their application, it is safe to say, 

 have been no more beneficial to the human 

 race than the researches which made known 

 the mode of development of plants and ani- 

 mals. Electricity and steam have fur- 

 nished power for the moving of ponderous 

 matter, but evolution has given a mental 

 force which has profoundly modified the 

 philosophies of all civilized peoples, and as 

 there is no doubt will be a means of dis- 

 covering many new truths in the future. 

 Advance in philosophy, ethics, etc., is no 

 less dependent on research than is the 

 growth of manufacture or commerce. But 

 no separation of purely intellectual and 

 purely industrial development is permis- 

 sible, since, as there is abundant evidence 

 for proving, progress in any department 

 of human activity is followed by gains at 

 other points along the frontier of the do- 

 main of the known. 



The Bounds of the Enowable not yet 

 Beached. — The incentive which leads men 

 to devote their time and energy to research 

 is an unquenchable thirst for knowledge. 

 The unknown has fascinations which in all 

 ages have awakened a response in the hu- 

 man breast. In the earlier stages of intel- 

 lectual development, the mountains, the 

 ocean, the caverns and other but little- 

 Imown portions of the earth were peopled 

 in imagination with gods, genii and fairies, 

 both genial and malign. When reason sup- 

 plants fancy and experiment undermines 

 credulity, the voices from the unknown be- 

 come still more alluring. They lead the 

 astronomer to explore distant space where 

 he finds no limit; the geologist to trace 

 backward the history of the earth without 

 discovering a beginning; the chemist and 

 physicist to scrutinize the laws governing 

 matter and force without untangling all 

 of their complexities; the archeologist, the 

 historian, the philosopher, the socialist and 

 others to investigate man's estate and de- 

 velopment, only to find the records failing 



before the beginning of thought is discern- 

 ible; the biologist to describe and classify 

 the manifold ways in which life is encased 

 and study the functions of bone, muscle and 

 nerve, only to learn that the longed-for in- 

 sight as to what life really is recedes far- 

 ther and farther as he advances. Along 

 these and many other tributaries of the 

 river of knowledge explanations have been 

 carried without reaching their sources. On 

 every hand and at no great distance, as 

 shown by the explorations that have been 

 made, the known merges with the unknown. 

 This same conclusion can be indicated in 

 another way: The rate and character of a 

 change that is taking place are frequently 

 indicated by means of a curved line, which 

 shows graphically, perhaps an increase, a 

 culmination and a decline. By this means 

 the rate at which human knowledge has in- 

 creased might be plotted, but the curve 

 would fail to indicate a maximum and give 

 no suggestion of a decline. The nineteenth 

 century has been termed the 'wonderful 

 century,' and why? Because during that 

 century scientific discovery, followed by in- 

 vention, was carried on more systemat- 

 ically, more enthusiastically and by a 

 larger number of sMHed investigators 

 than during any previous century. The 

 tide of discovery and invention which 

 made itself prominent during the cen- 

 tury recently closed, and increased in force 

 as the years of that century increased 

 in number, is still advancing and, as it 

 seems, with continuous acceleration. The 

 intellectual tide-gauges of the world give 

 no suggestion that the nineteenth-century 

 wave of discovery has culminated. On the 

 contrary, there is abundant evidence to 

 show that the rate of intellectual develop- 

 ment is still on the increase, and that yet 

 more important conquests in the domain of 

 the unknown than have illuminated the 

 past will be made in the future. On our 



