Epilogue 
385 
where none had existed that were appropriate. Some of his 
ideas have been developed by younger men, till they have be¬ 
come distinct divisions of the larger science to which they be¬ 
long. 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 mak¬ 
ing 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 ir¬ 
rigable 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 endeav¬ 
oured to bring about. 
Of late years when he might have relaxed his labours, he 
turned his attention to the field of psychology and phik 
osophy, working till his malady, sclerosis of the arteries, 
produced his last illness. The result was two treatises in this 
line, TrittJi 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 Ameri- 
caji 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 direct thought, and for many years very 
close to Powell): “His philosophic writings belong to a field 
