Other than the corrections listed below, printer's inconsistencies in spelling, punctuation, hyphenation, and ligature usage have been retained. The following misprints have been corrected: changed "book-case" into bookcase page 127 added ' before I am sure,' page 120 added ' after there are no flies here, page 145 added ' after possibly carry out. page 145 Illustrations have been moved from the middle of a paragraph to the closest paragraph break.