I Regret that so long an interval should have elapsed between the first announced of these Lectures and their publication; and I owe my thanks to the Committee of the Union for their patience in waiting for them. But I can hardly charge myself with any fault. The results of a very serious accident, and frequent and prolonged interruptions to health, prevented my touching my task for nearly two years after it was first proposed to me.<br><br>These things, together with a feebleness of voice, which made me doubt whether it would not be scant courtesy to the public to allow an audience to be invited to hear what might, in great part, be inaudible, led me to shrink from all thought of oral delivery. This deviation from the usual course, how ever, is perhaps greater in appearance than reality; since it rarely happens that more than portions of a series of Lectures of this kind can be given in the time to which the speaker must necessarily restrict himself. They are in general largely supplemented and expanded before publication.<br><br>As the Lectures were not to be delivered, I naturally paid less attention than I should have done to those minute proprieties which, I am well aware, ordinarily distinguish spoken from written composition. I have also taken advantage of the same circumstance to determine the length of each Lecture, rather by the nature of the subject than by the Lecturers hour glass.<br><br>It is often a valuable and interesting feature of volumes of this class (at least it is so in my estimation), that they contain a large supplement of references and citations, for the illustration or corroboration of the Lecturers