TRANSCRIBER'S NOTES
The transcription of this work was made by David Wilkins from School of Mathematics Trinity College, Dublin who kindly authorized its use by Project Gutenberg.
Revision of this work was made by Prof. Stanley Burris from University of Waterloo.
Equation {11} was numbered twice by the author. They were renumbered as {11a} and {11b} respectively.
Footnotes [2], [3] and [5] have been added by this Transcriber for the sake of clarity in the text. The cover image was created by the Transcriber and placed in the public domain.