faithfully employ all the intervening days in collecting and digesting the materials, whether I have or have not lectured on the same subject before, making no difference. The day of the lecture, till the hour of commencement, I devote to the consideration, what of the mass before me is best fitted to answer the purposes of a lecture, that is, to keep the audience awake and interested during the delivery, and to leave a sting behind, that is, a disposition to study the subject anew, under the light of a new principle. Several times, however, partly from apprehension respecting my health and animal spirits, partly from the wish to possess copies that might afterwards be marketable among the publishers, I have previously written the lecture; but before I had proceeded twenty minutes, I have been obliged to push the MS. away, and give the subject a new turn. Nay, this was so notorious, that many of my auditors used to threaten me, when they saw any number of written papers on my desk, to steal them away; declaring they never felt so secure of a good lecture as when they perceived that I had not a single scrap of writing before me. I take far, far more pains than would go to the set composition of a lecture, both by varied reading and by meditation; but for the words, illustrations, &c., I know almost as little as any one of the audience (that is, those of anything like the same education with myself) what they will be five minutes before the lecture begins. Such is my way, for such is my nature; and in attempting any other, I should only torment myself in order to disappoint my auditors--torment myself during the delivery, I mean; for in all other respects it would be a much shorter and easier task to deliver them from writing. I am anxious to preclude any semblance of affectation; and have therefore troubled you with this lengthy preface before I have the hardihood to assure you, that you might as well ask me what my dreams were in the year 1814, as what my course of lectures was at the Surrey Institution. 'Fuimus Troes'."