8 



rSXT FIGURES. 



Page. 

 Fig. 1. Centrifuge, shaker, and electric motor used in mechanical analysis of 



soils 28 



2. Tubes of galvanized iron used to study effectiveness of mulches u|)on 



moisture losses - 40 



8. King's aspirator to determine the effective size of soil grains 41 



4. Apparatus used to study the movement of air through soils 43 



5. Apparatus used to study percolation <»f water through soils 44 



6. Hot-air drying oven 46 



7. Centrifugal seed-grading machine 51 



8. Movable soil thermometer 53 



9. Soil sampling apparatus 54 



10. Apparatus for determining specific gravity of soils 60 



11. Determination of volume weight, apparent specific gravity, and poros- 



ity of soils 61 



12. Soil-compacting machine 62 



13. Determining the power of soils to retain moisture 63 



14. Rate of percolation of water through soils 64 



15. Apparatus to determine the rate of flow of air through soils 65 



16. Soil tubes for showing the effect of nmlches on evaporation of water 



from soils 65 



17. Determining the power of air-dry soils to al)sor]) moisture from tlie air. 66 



18. Measuring capillarity in soils - 67 



19. Apparatus for testing the adhesiveness of soils 08 



20. Card's apparatus for testing the adhesiveness of soils 09 



21 . Apparatus for taking soil samples 70 



22. Plan of experiment grounds at (Jottingen Agricultural institute 83 



