In _Science_, April 15, 1910, there appeared an open letter written by Professor B. C. Gruenberg of De Witt Clinton School, New York, along the very lines I have indicated. I quote a paragraph:— “We all know that there can be no true science that does not rest solidly upon facts. But the thought must often occur to many of us that there is some danger, especially among the younger scientists, that we may become obsessed with an exaggerated sense of the value of facts as such. Is there not too much emphasis laid by many professors in charge of research students on the mere accumulation of observational, statistical, or experimental facts, with too little attention to that side of science which concerns itself with those analytical and synthetic processes that convert facts into valuable ideas? It seems to me that this latter kind of work needs at the present time at least as much encouragement as the other. Of course, there is the possibility for ‘thinking’ to degenerate into profitless speculation; but we are certainly as much in need of the results of thinking about the facts already accumulated as we are of more facts.” Such studies as those of Professor Holmes on pottery and quarries; such explorations as Mr. C. B. Moore’s in the South; the work done by Volk and Abbott in New Jersey, where they very carefully set aside the argillite and the quartzite and chipped implements as found in different places under different conditions; such work as Professor Mills has done in Ohio in differentiating the Hopewell and the Fort Ancient culture, are things that will count, and works that will stand. A surveyor should measure mounds, number skeletons, and draw plans. The librarian should read reports and compile statistics, but it requires a real archæologist to do the work that I have referred to above. Squier and Davis, whose “Ancient Monuments of the Mississippi Valley” may be justly considered our standard work upon the mounds, not only explored, but they drew conclusions which, with here and there an exception, or a slight change, will stand at the present time. For many years Dr. Cyrus Thomas used all the tremendous energies of the Bureau of Ethnology to dispute the statements of those hard-working, painstaking, philosophical pioneers Squier and Davis. To-day we know that the culture they described is different from the Shawano, Cherokee, or other cultures which Thomas wished to establish in the Ohio Valley. The work of that distinguished citizen of Illinois, George Sellars, will bear comparison with the work of any other man since his day in the study of chipped flint objects, and if any one doubts the statement let him read and ponder upon Sellars’s complete narrative in the Smithsonian Report for 1885, and then read what has been said since by others.