PREFACE. ix 
historical sketch of the legislation relating to swamp lands and executive 
action thereunder; another chapter on bounty lands and land grants for 
agricultural schools, and still another on land grants in aid of internal 
improvements—chiefly railroads. The latter chapter has already been 
prepared by Mr. Willis Drummond, jr., and as the necessary map is ready 
I have concluded to publish it now, more especially as the granted lands 
largely lie in the Arid Region. Mr. Drummond’s chapter has been carefully 
prepared and finely written, and contains much valuable information. 
To the late Prof. Joseph Henry, secretary of the Smithsonian Insti- 
tution, I am greatly indebted for access to the records of the Institution 
relating to rainfall. Since beginning my explorations and surveys in the 
far west, I have received the counsel and assistance of the venerable 
professor on all important matters relating to my investigations ; and what- 
ever of value has been accomplished is due in no small part to his wisdom 
and advice. I cannot but express profound sorrow at the loss of a coun- 
selor so wise, so patient, and so courteous. 
Iam also indebted to Mr. Charles A. Schott, of the United States 
Coast Survey, to whom the discussion of the rain gauge records has been 
intrusted by the Smithsonian Institution, for furnishing to me the required 
data in advance of publication by himself. 
Unfortunately, the chapters written by Messrs. Gilbert, Dutton, Thomp- 
son, and Drummond have not been proof-read by themselves, by reason of 
their absence during the time when the volume was going through the 
press; but this is the less to be regretted from the fact that the whole 
volume has been proof-read by Mr. J. C. Pilling, whose critical skill is all 
that could be desired. 
J WOR: 
Avueust, 1878. 
sae 
