idea.  Gilbert truly says, “it is not easy to separate the product of his personal work from that which he accomplished through the organisation of the work of others.  He was extremely fertile in ideas, so fertile that it was quite impossible that he should personally develop them all, and realising this, he gave freely to his collaborators.  The work which he inspired and to which he contributed the most important creative elements, I believe to be at least as important as that for which his name stands directly responsible."*

* Science, Oct. 10,1902.  See also “John Wesley Powell,” edited by G. K. Gilbert, reprinted from The Open Court, 1903.

In the field of geology he was particularly facile in the invention of apt descriptive terms, and indeed he was never at a loss for words to express new meanings, coining them readily where none had existed that were appropriate.  Some of his ideas have been developed by younger men, till they have become distinct divisions of the larger science to which they belong.  His greatest work in the Geological Survey, that which was more the result of his personal effort, may be summed up under three heads:  First, the development of a plan for making a complete topographic map of the United States; second, the organisation of a Bureau for the collection of facts and figures relating to the mineral resources of the country; and third, his labours to preserve for the people the waters and irrigable lands of the Arid Region.  It is hard to say which of these is greater or which was nearer his heart.  Together they constitute a far-reaching influence in the development of the country such as no one man heretofore has contributed.  His Studies and recommendations with regard to the arid lands of the West are of the greatest importance to that district and to the country at large and the nearer they can be carried out the better will it be for posterity.  He perceived at once that the reservation of sites for storage reservoirs was of the first importance and this was one of the earliest steps he endeavoured to bring about.

Of late years when he might have relaxed his labours, he turned his attention to the field of psychology and philosophy, working till his malady, sclerosis of the arteries, produced his last illness.  The result was two treatises in this line.  Truth and Error, published in 1899, and “treating of matter, motion, and consciousness as related to the external universe or the field of fact,” as Gilbert describes it, and Good and Evil, running as a series of essays in the American Anthropologist, treating of the same factors as related to humanity or to welfare.  A third volume was planned to deal with the emotions, and he had also woven these ideas into a series of poems, of which only one has been published.  Few understand these later products of Powell.  Many condemn them; but Gilbert expresses his usual clear, unbiassed view of things and says (and I can do no better than to quote him, a man of remarkably