178 University Geological Survey of Kansas. 
the operations of the district and who desire to familiarize 
themselves with it in the shortest time and the simplest way. 
However, accuracy has not been sacrificed to brevity or sim- 
plicity. 
The sources from which the information has been derived 
are: Personal visits to mines and mills and the manufactur- 
ers of mine and mill machinery, and, finally, technical litera- 
ture. 
The writer is especially indebted to both mine and mill 
owners and operators for their interest in the work, little of 
which could have been done without their assistance and co- 
operation. Although considerable time has elapsed since 
the actual field work was done, yet the methods, in many 
lines, have changed but little. Nevertheless changes have 
taken place and in many and varied ways, and although the 
writer has in a way kept in touch with the practice both by 
occasional visits and correspondence, yet no attempt has been 
made to change the body of the report. Results previously 
obtained have been, in some instances, recast and some new 
matter introduced by the addition of another chapter — 
Addenda. 
Special acknowledgments are due to Prof. Erasmus Ha- 
wortH, the Director of the University Geological Survey, for 
directions and suggestions regarding the work and for hearty 
cooperation both in the field and office; to Dr. A. F. Roaurs, 
Mineralogist for the Survey, for his cordial and efficient 
assistance in many ways; and to Prof. H. S. Munro, pro- 
fessor of Mining, Columbia School of Mines, for much valuable 
information and many suggestions relative to mining and 
milling methods. We Pe Omanl 
UNIVERSITY OF KANSAS, October 1, 1904. 
