CONTENTS. 



VII 



Depaktment Bulletin No. 1018 — Water-stress Behavior of Pima Cotton 



in Arizona — Continued. Page. 



Shedding studies under Arizona conditions 12 



The period between flowering and shedding 15 



Variations in periodicity of development 15 



Conclusions 21 



Literature cited 23 



Department Bulletin No. 1019. — Marketing Broom Corn: 



Use and importance of crop 1 



Preparation for market 2 



Selection of brush 3 



What not to harvest 3 



Threshing 4 



Curing 7 



Baling 10 



Marketing at country points 11 



Kinds of dealers 11 



Time of movement ' 15 



Principal country shipping points 16 



Opening the market 16 



Methods of marketing 18 



Sampling 25 



Country storage 26 



Transportation 28 



Methods of loading at country points 28 



Channels of traffic 29 



Principal terminal and manufacturing points 30 



Cooperative marketing 30 



Department Bulletin No. 1020. — Harvest Labor Problems in the Wheat 

 Belt: 



Scope of the investigation 1 



Fluctuations of harvest labor demand 3 



Character of harvest labor 14 



Mobilization of harvest labor 22 



Distributions of harvest labor 26 



Harvest wages 30 



Conclusions 34 



Department Bulletin No. 1021. — Group Classification and Varietal 

 Descriptions of American Varieties of Sweet Potatoes: 



Importance of varietal classification of sweet potatoes 1 



Early attempts at classification 2 



Proposed system of classification 4 



Key to the groups 6 



Descriptions of the groups 6 



List of varieties included in the key 11 



Descriptions of varieties 11 



Check list of names used in sweet-potato literature 18 



Bibliography of sweet-potato literature 26 



Department Bulletin No. 1022. — Relation of Initial Temperature, 

 Vacuum, and Temperature Changes in the Container During Canning 

 Operations: 



Canning problems 1 



Review of the literature '. -. 1 



Need for study of initial temperature in its relation to pressure and vacuum . 4 



Methods and apparatus 6 



Theoretical pressures and vacuums 9 



Experiments with distilled water for comparison 12 



Experiemnts with specific food materials 19 



Summary 50 



Literature cited 52 



