The Table of Contents was created by the transcriber. Illustrations have been moved to paragraph breaks near where they are mentioned. Punctuation has been made consistent. Variations in spelling and hyphenation were retained as they appear in the original publication, except that obvious typos have been corrected. Changes have been made as follows: p. 3: Caption added to figure (Fig. 1.) p. 40: Caption added to figure (Fig. 2.) p. 41: Caption added to figure (Fig. 1.) p. 56: Caption added to figure (Fig. 2.)