94 



between known and unknown, which for me has always had peculiar 

 temptations. I venture to think that the greatest scientific problems of 

 the future will find their solution in this borderland, and even beyond ; 

 here, it seems to me, lie ultimate realities, subtle, far-reaching, wonderful." 



The developments of the last few years have demonstrated that no 

 truer prophecy was ever uttered, and the prophet Crookes has lived to 

 witness and to take a part in its fulfillment. 



The importance of the present rejuvenation of physical science does 

 not consist alone in the abundance of the harvest. There have been 

 abundant harvests in the past. Consider the decade which closed one 

 hundred years ago. In 1798 Rumford boiled water by friction. In 1799 

 Davy melted ice by friction in a vacuum and Laplace published his work 

 on mechanics. In 1S0O Yolta constructed the Voltaic pile, Nicholson and 

 Carlisle decomposed water, Davy discovered the properties of laughing 

 gas, and Herschel discovered dark heat rays. In 1801 Piazzi discovered 

 the first asteroid, Eitter the chemical rays, and Young the interference of 

 light. In 1802 Wedgewood and Davy made sun pictures by the action of 

 light on silver chloride, and Wollaston discovered dark lines in the sun's 

 spectrum. In 180S Malus discovered polarization by reflection, Gay 

 Lussac the combination of gases by multiple volumes, and Dalton the law 

 of multiple proportions. 



So great was the exhilaration and satisfaction produced by these dis- 

 coveries that many scientists of that period appear to have become infected 

 with something akin to the "sixth decimal" delusion. "Electricity," wrote 

 the French scientist Haliy, "enriched by the labor of so many distin- 

 guished physicists, seems to have reached the term when a science has no 

 more important steps before it. and only leaves to those who cultivate it 

 the hope of confirming the discoveries of their predecessors and of casting 

 a brighter light on the truths revealed." A statement which was almost 

 immediately followed by the discoveries of Oersted, Ampere, Seebeck and 

 Faraday. A statement which has been followed by the telegraph, the tele- 

 phone, the dynamo, the motor, the electric light, the electric railway, the 

 Roentgen rays, and the wireless telegraph and telephone. 



If anyone today is disposed to criticise the men of science of other 

 times because of their limited view, their complacent opinions and their 

 intolerance of all that did not agree with theories they considered estab- 

 lished, let him first read and ponder over what One spake about motes and 

 beams. 



