Thus even seventy years ago and more the United States had by honest, painstaking labour made worthwhile additions to human knowledge and these contributions have naturally multiplied a hundredfold with the lapse of years. Yet it would be quite misleading to make it appear as if the total represented merely a vast accumulation of uninspired routine jobs. Some years ago, to be sure, an American writer rather sensationally voiced his discontent with the paucity of celebrated _savants_ among our countrymen. But he forgot that in science fame is a very inadequate index of merit. The precise contribution made by one man’s individual ability is one of the most tantalizingly difficult things to determine--so much so that scholars are still debating in what measure Galileo’s predecessors paved the way for his discoveries in dynamics. For a layman, then, to appraise the relative significance of this or that intellectual worthy on the basis of current gossip is rather absurd. Certainly the lack of a popular reputation is a poor reason for denying greatness to a contemporary or even near-contemporary scientific thinker. Two remarkable instances at once come to mind of Americans who have won the highest distinction abroad yet remain unknown by name to many of their most cultivated compatriots. Who has ever heard of Willard Gibbs? Yet he was the recipient of the Copley medal, British learning’s highest honour, and his phase rule is said to mark an epoch in the progress of physical chemistry. Again, prior to the Nobel prize award, who outside academic bowers had ever heard of the crucial experiment by which a Chicago physicist showed, to quote Poincaré, “that the physical procedures are powerless to put in evidence absolute motion”? Michelson’s name is linked with all the recent speculations on relativity, and he shares with Einstein the fate of finding himself famous one fine morning through the force of purely external circumstances.