Whilst the greatest effort has been made to ensure the quality of this text, due to the historical nature of this content, in some rare cases there may be minor issues with legibility. I take this opportunity to express publicly my high appreciation of the honour done me by the great institutions of learning above mentioned in their invitations to address them, and also of the generous courtesy with which I was received by their officers and students. The proofs of the volume have been read by my colleagues, Professors Wendell, Kittredge, and Neil son. I am much indebted to them for this service.