LIST OF ILLUSTRATIONS. 



Page. 

 Fig. 1. A piece of sawn timber cut through along the pith, illustrating its 



structural aggregates 9 



2. Possibilities of cutting timber from a log with reference to position of 



grain 9 



3. Board of pine 15 



4. Wood of spruce 16 



5. Group of fibers from pine wood 17 



6. Block of oak 18 



7. Board of oak 18 



8. Cross section of oak 19 



9. Isolate tl fibers and cells 20 



10. Cross section of basswood (magnified) 21 



11. Spiral grain 22 



12. Alternating spiral grain in cypress 22 



13. Wavy grain in beech 22 



14. Section of wood showing position of the grain at base of a limb 23 



15. Cross section of a group of wood fibers 25 



16. Isolated fibers 26 



17. Orientation of wood samples 27 



18. Short pieces of wood fiber 32 



19. Isolated cell 32 



20. Warping of wood 32 



21. Formation of checks 33 



22. Small pith ray in oak 34 



23. Effects of shrinkage 35 



24. Honeycombed board 36 



25. Bending a beam 39 



26. Specimen in tension test 43 



27. Straight and cross grained wood 43 



28. Effect of knots and their position 43 



29. Compression endwise 44 



30. Longitudinal shearing 44 



31. Various forms of failure 45 



32. Test iu hardness and shearing across the grain 47 



33. Cleavage 48 



34. " Shelf-fungus on the stem of a pine 55 



35. Fungus threads in pine wood 55 



36. Cells of maple wood attacked by fungus threads 56 



37. Nonporous woods 60 



38. Ring -porous woods 61 



39. Dirt use-porous woods 61 



40. Wood of coffee tree 66 



41. Wood of black, white, and green ash 67 



42. Wood of red oak 68 



43. Wood of chestnut 68 



44. Wood of* hickory 68 



45. Wood of beech, sycamore, and birch 70 



46. Wood of maple 70 



47. Wood of elm 71 



48. Wood of walnut 71 



49. Wood of cherry 71 



4 



