Nowadays one cannot be a scholar in general. One has to have some specialty. As to what that specialty shall be in terms of usefulness to the community, I think I have given you examples enough to show that the range is almost unlimited. I had planned to sum up this by a brief record of the discovery and application to war purposes of helium; but I find that one of my own students in Columbia College, now a member of the Geological Survey, has beaten me out; and you can find the whole story in the May issue of the _National Geographic Magazine_. I cannot resist, however, a summary of the steps. First, the astronomer, just about the time this chapter was established, finds a new line in the solar spectrum. Thirty years later, the geologist comes upon an unusual stone and turns to a great chemist for its analysis, with the consequent recognition of helium as a mundane element. About the same time comes its identification as one of the newly recognized ingredients of the air, and the study of its properties. Then a Kansas chemist discovers its presence in some natural gas about which he was consulted because it would not burn properly. Then comes the war with its incendiary bullet and the need of a non-inflammable content for balloons and dirigibles. Then the coöperation of physicist, engineer, and geologist--Canadian and American--makes helium available for this purpose. Before these researches helium cost $1700 a cubic foot and was obtainable only in Germany. The present price is 10 cents a cubic foot, and it is falling. The importance of all this for peace is very great. In these days of airplane hops we are forgetting that a Zeppelin made the trip from Bulgaria to what should have been German East Africa with medicines and ammunition. The Germans having disappeared in the meantime, the Zeppelin turned around and came back, making a continuous voyage of several thousand miles. But do not forget that not all scholars made good in the great test. Let me sum up what I have already said. In the first place, to be useful the scholarship must be sound. The near-scholar, the man who took the short-cut in preparation, proved to be a positive danger. The mere expert in some narrow field, the man who did not realize the implications of what he knew, was relatively useless. A man to succeed had to be intense without being narrow. Even among the sound scholars, the men who really knew, the isolated and insulated individual could very rarely make much headway. It was the open-minded scholar, the maker and keeper of friends, who got his chance, the scholar whose learning was to him a living thing, not necessarily to be displayed in the market place, and never for the sake of the display, but on the other hand never wrapped in a napkin and buried in the earth.