Transcriber's Notes:
Some minor typographical errors have been corrected.
Inconsistencies in spelling (including hyphenation) and formatting have not been corrected, except that sand-paper has been changed to sandpaper.
In the multi-page table, repeated headings and carry forward / carried forward have been removed.
Illustrations have been moved to the paragraph where they are described. Some illustrations have been rotated so that most of the text is displayed horizontally.