PREFACE
This book was written under exceedingly trying circumstances. The author had a severe attack of influenza in November last and passed through a great crisis, his life having been despaired of for a time. On recovering a little, but while still bed-ridden, he dictated these lectures from his sick-bed to one of his sons–as a means of driving away the feelings of despair and the gloomy thoughts natural to one suffering from such a serious illness. The readers will, it is hoped, excuse the defects and shortcomings that may have arisen under such circumstances. The proofs could not be revised by him with care. It is, however, his duty to acknowledge with thanks the friendly help he received from Mr. C. S. Paterson, M. Sc., who revised some proofs of the first portion of the book. But as he left the city, shortly after the work had been sent to the press, the author could not avail himself of his kind and disinterested help for long.
The author has taken great pains in the preparation of these lectures. Though most of
