iv PREFACE. 



Stress has been laid, in the discussion of manufacturing methods, 

 on the general chemical and physical principles which underlie these 

 methods rather on the details which differ at every plant and may 

 change with every year. So far as possible, however, such details as 

 bear on labor, power, and costs have been carefully discussed, and it 

 is believed that the estimates furnished are entirely reliable. 



The writer's acknowledgments are due to Engineering News, Munici- 

 pal Engineering, Engineering Record, Engineering and Mining Journal, 

 Cement, and The Iron Age for permission to use illustrations and to 

 reprint parts of articles which had appeared first in their columns. To 

 an even greater extent he is indebted to the chemists and managers 

 of American cement-, lime-, and plaster-plants, and to manufacturers 

 of different lines of machinery, for data and illustrations which they 

 have kindly furnished for use in this volume. 



It may not be out of place to state that this volume was planned 

 and partly written in 1901. If it had been published at that date the 

 words "probably" and " possibly" would not have occurred so fre- 

 quently as they do in the present work, for at that time the writer felt 

 a cheerful certainty in regard to many points which now seem less 

 obvious. A wider personal experience, taken in connection with the 

 remarkable changes which have recently affected both the theory and 

 practice of cement-manufacture, has resulted in a more cautious treat- 

 ment of certain phases of the subject. 



WASHINGTON, D. C., March 6, 1905. EDWIN C. ECKEL. 



