CONTENTS. 



Department Bulletin No. 501. — A Study in the Cost op Producing Milk 

 ON Four Dairy Farms, Located in Wisconsin, Michigan, Pennsylvania, 



AND North Carolina: Page.. 



The scope of the study 1 



Locations and descriptions of farms where cost records were obtained 2 



Methods of procuring data 4 



Factors involved in the cost of producing milk 4 



Data from other sources 19 



Discussion of results 21 



Relation of individual cow to cost of production 29 



Summary 33 



Literature cited 34 



Department Bulletin No. 502. — The Drainage of Irrigated Shale 

 Land: 



Introduction 1 



Geological features 2 



Surface topography 3 



Underground water 4 



AlkaU 7 



Drainage methods 11 



Construction 20 



Cost data 22 



Examples of methods 23 



Results of drainage 38 



Conclusions 39 



Department Bulletin No. 503. — Turnips, Beets, and Other Succulent 

 Roots, and Their Use as Food: 



Introduction 1 



Food value of succulent roots 3 



Root vegetables less commonly known 14 



Roots used as condiments 15 



Summary 17 



Department Bulletin No. 504. — The Theory or Correlation as Applied 

 TO Farm Survey Data on Fattening Baby Beef: 



Introduction 1 



Theory of correlation 1 



Computation of coefficients 6 



Interpretations of the coefficients 8 



Summary 13 



Department Bulletin No. 505.- — Digestibility of Some Vegetable Fats: 



Introduction 1 



Experimental methods 1 



Digestion experiments — Olive oil, cottonseed oil, peanut oil, coconut oil, 



sesame oil, cocoa butter 2 



Conclusions 18 



Department Bulletin No. 506.^ — Production op Lumber, Lath, and 

 Shingles in 1915 and Lumber in 1914: 



Introduction 1 



Method of compilation 4 



Production, by classes of mills 6 



Production, by States 7 



Production, by kinds of wood 13 



Lath 34 



Shingles 35 



Lumber values 36 



Detailed summary 37 



Appendix — 1914 statistics 42 



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