Perhaps these opinions of one whose lips are now silent will yet have their weight in the discussion of this question both in our highest seats of learning and in those educational parliaments which have been lately called into existence in almost every town and district of our country.
From the somewhat disparaging remarks about lectures quoted above, it must not be supposed that this prince of lecturers depreciated his office. "Lectures," he said, "depend entirely for their value upon the manner in which they are given. It is not the matter, it is not the subject, so much as the man; but if he is not competent, and does not feel that there is a need of competency, to convey his ideas gently and quietly and simply to the young mind, he simply throws up obstacles, and will be found using words which they will not comprehend." These were the words of his later days, but fortunately he felt "the need of competency" before his own habits were formed, and in four letters to Abbott we find wonderfully sagacious observations on the matter, which it would be well for any young lecturer to study. He describes the proper arrangement of a lecture-room, dwelling on the necessity of good ventilation; and then, having considered the fittest subjects for popular lectures, he turns to the character of the audience, and shows how that must be studied; for some expect to be entertained by the manner of the lecturer as well as his subject, while others care for something which will instruct. He dwells on the superiority of the eye over the ear as a channel of knowledge, and lays down some rules for this kind of instruction, which he of all men subsequently carried out to perfection. "Apparatus is an essential part of every lecture in which it can be introduced.... Diagrams and tables, too, are necessary, or at least add in an eminent degree to the illustration and perfection of a lecture. When an experimental lecture is to be delivered, and apparatus is to be exhibited, some kind of order should be observed in the arrangement of them on the lecture table. Every particular part illustrative of the lecture should be in view; no one thing should hide another from the audience, nor should anything stand in the way of or obstruct the lecturer. They should be so placed, too, as to produce a kind of uniformity in appearance. No one part should appear naked and another crowded, unless some particular reason exists and makes it necessary to be so. At the same time the whole should be so arranged as to keep one operation from interfering with another." A good delivery comes in for its share of praise; "for though to all true philosophers science and nature will have charms innumerable in every dress, yet I am sorry to say that the generality of mankind cannot accompany us one short hour unless the path is strewed with flowers." Then, "a lecturer should appear easy and collected, undaunted and unconcerned, his thoughts about him, and his mind clear and free for the contemplation and description of his subject. His action should not be hasty and violent, but slow, easy, and natural, consisting principally in changes of the posture of the body, in order to avoid the air of stiffness or sameness that would otherwise be unavoidable. His whole behaviour should evince respect for his audience, and he should in no case forget that he is in their presence." He allows a lecturer to prepare his discourse in writing, but not to read it before the audience, and points out how necessary it is "to raise their interest at the commencement of the lecture, and by a series of imperceptible gradations, unnoticed by the company, keep it alive as long as the subject demands it." This of course forbids breaks in the argument, or digressions foreign to the main purpose, and limits the length of the lecture to a period during which the listeners can pay unwearied attention. He castigates those speakers who descend so low as "to angle for claps," or who throw out hints for commendation, and shows that apologies should be made as seldom as possible. Experiments should be to the point, clear, and easily understood: "they should rather approach to simplicity, and explain the established principles of the subject, than be elaborate and apply to minute phenomena only.... 'Tis well, too, when the lecturer has the ready wit and the presence of mind to turn any casual circumstance to an illustration of his subject." But experiments should be explained by a satisfactory theory; or if the scientific world is divided in opinion, both sides of the question ought to be stated with the strongest arguments for each, that justice may be done and honour satisfied.