﻿CONTENTS 



Page 



Depaktment Bulletin No. 1373. — Dttst Control in Grain Eleva- 

 tors: 



Introduction 1 



Purpose of investigation ' 2 



Procedure 2 



Methods of dust control 3 



Dust collection 4 



Dust removal 22 



Natural ventilation 31 



Mechanical ventilation 33 



Dust-control equipm'ent 34 



Fans 34 



Piping system 34 



Dust collectors 35 



Grain traps 35 



Suction regulators 36 



Effect on grain weights 46 



Conclusions 48 



Department Bulletin No. 1374. — Studies of the Pink Bollworm 

 IN Mexico: 



Inception and scope of the work 1 



Distribution of the pink boUworm 2 



Habits 3 



Damage caused bv the pink bollworm 15 



Food plants '. 28 



Dissemination by flight 29 



Natural control 31 



Repression , 37 



Summary 63 



Department Bulletin No. 1375. — The Brown-Duvel Moisture 

 Tester and How to Operate it: 



Description of the apparatus 3 



Construction specifications 4 



Description of accessories 5 



Supply pipes for gas-heated moisture testers 15 



How to make a moisture test 17 



How to test different substances 18 



Standardizing the moisture tester 20 



Variations in heating time caused by variations in gas pressure 23 



Variations in heating time and moisture-test result caused by position 



and condition of wire gauze 28 



Variations in heating time caused by variations in thermometer bulb 



immersion 29 



Influence of cooling time on moisture-test results 30 



Priming tests 31 



Volume of oil versus moisture-test result 33 



Brown-Duvel moisture testers equipped with electric heaters 33 



Tests with alcohol and gasoline burners 39 



How to choose extinguishing temperatures 39 



Drawing and handling samples 41 



Special points for consideration 42 



