viii TABLE OF CONTENTS 



PAGE 



26. The Form of Logs 18 



27. Formulae for Solid Contents of Logs 19 



28. Relative Accuracy of the Smalian and Huber Formulae 21 



29. The Technique of Measuring Logs 22 



30. Girth as a Substitute for Diameter in Log Measurements 24 



CHAPTER IV 

 LOG RULES BASED ON CUBIC CONTENTS 



31. Comparison of Log Rules Based on Diameter at Middle and at Small End 



of Log 26 



32. Log Rules in Use, Based on Cubic Volume 28 



33. The Blodgett or New Hampshire Cubic Foot 30 



34. Use of Cubic Foot in Log Scaling 31 



35. Log Rules for Cubic Contents of Squared Timbers 33 



36. Log Rules Expressed in Board-feet but Based Directly upon Cubic Contents 34 



37. Formula for Board-foot Rules Based on Cubic Contents 35 



38. Comparison of Scaled Cubic Contents by Different Log Rules 36 



39. Relation between Cubic Measure and True Board-foot Log Rules 39 



CHAPTER V 

 THE MEASUREMENT OF LOGS. BOARD-FOOT CONTENTS 



40. Necessity for Board-foot Log Rules 40 



41. Relation of Diameter of Log to per cent of Utilization in Sawed Lumber ... 40 



42. Errors in Use of Cubic Rules for Board-feet 42 



43. Taper as a Factor in Limiting the Scaling Length of Logs for Board-foot 



Contents 43 



44. The Introduction of Taper into Log Rules 44 



46. Middle Diameter as a Basis for Board-foot Contents 46 



46. Definition and Basis of Over-run 46 



47. Influences Affecting Over-run. The Log Rule Itself 47 



48. Influences Affecting Over-run. Methods of Manufacture 47 



49. Standardization of Variables in Construction of a Log Rule 49 



50. The Need for More Accurate Log Rules 50 



61. The Waste from Slabs and Edgings 50 



62. The Waste from Crook or Sweep 51 



53. The Waste from Saw Kerf 53 



64. Total Per Cent of Waste in a Log 55 



CHAPTER VI 



THE CONSTRUCTION OF LOG RULES FOR BOARD-FOOT 



CONTENTS 



66. Methods Used in Constructing Log Rules for Board-feet 58 



56. The Construction of Rules Based on Mathematical Formula? 59 



67. Comparison of Log Rules Based on Formulae 61 



58. McKenzie Log Rule 63 



59. International Log Rule for J" Kerf, Judson F. Clark, 1900 63 



