19. What are the two methods of kiln-drying? Describe the principle of the moist air kiln. What is claimed of it? How should hard wood lumber be treated before being kiln-dried?
20. Describe the induced draft system. What devices are used to extract the moisture from the heated air? What are the main points of difference between the two systems?
21. What is the difference in the condition of lumber which may be put in the two forms of kilns? Which is the more expensive system to install and operate? How do users of the two systems compare them?
22. How should lumber be stacked in the kiln?
23. How long should lumber generally remain in the kiln to allow the moisture to be extracted? How long to insure most permanent results?
24. How should kiln-dried lumber be cared for?
25. What is the effect of steaming wood?
26. How is wood sometimes treated to preserve it from the elements and from insects?
CHAPTER IV
Tools