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. It also may seem that many things have been omitted which should have been included. The author is only too well aware that he may be open also to this charge. But in a short treatise to serve a special purpose, these unavoidable omissions are inevitable. Perhaps he has been unconscious of certain important aspects of the subject, which maturer thought on a novel problem would have revealed to him.