A lecturer falls deeply beneath the dignity of his character when he descends so low as to angle for claps and asks for commendation. Yet have I seen a lecturer even at this point. I have heard him causelessly condemn his own powers. I have heard him dwell for a length of time on the extreme care and niceness that the experiment he will make requires. I have heard him hope for indulgence when no indulgence was wanted, and I have even heard him declare that the experiment now made cannot fail, from its beauty, its correctness, and its application, to gain the approbation of all.... I would wish apologies to be made as seldom as possible, and generally only when the inconvenience extends to the company. I have several times seen the attention of by far the greater part of the audience called to an error by the apology that followed it. ’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. Any particular circumstance that has become table-talk for the town, any local advantages or disadvantages, any trivial circumstance that may arise in company, give great force to illustrations aptly drawn from them, and please the audience highly, as they conceive they perfectly understand them. Apt experiments (to which I have before referred) ought to be explained by satisfactory theory, or otherwise we merely patch an old coat with new cloth, and the whole [hole] becomes worse. If a satisfactory theory can be given, it ought to be given. If we doubt a received opinion, let us not leave the doubt unnoticed and affirm our own ideas, but state it clearly, and lay down also our objections. If the scientific world is divided in opinion, state both sides of the question, and let each one judge for himself by noticing the most striking and forcible circumstances on each side. Then, and then only, shall we do justice to the subject, please the audience, and satisfy our honour, the honour of a philosopher. [Sidenote: USE OF CRITICISM.] One who already had set before himself such high ideals could not fail at least to attempt to fulfil them. Accordingly, when in 1816 he began to lecture to the City Philosophical Society, he began to attend an evening class on elocution conducted by Mr. B. H. Smart, though the pinch of poverty made it difficult to him to afford the needful fees. Again, in 1823, previous to taking part in Brande’s laboratory lectures, he took private lessons in elocution from Smart, at the rate of half-a-guinea a lesson. After 1827, when he was beginning his regular courses of lectures in the theatre, he often used to get Mr. Smart to attend in order to criticise his delivery. Amongst the rules found in his manuscript notes were the following:-- Never to repeat a phrase. Never to go back to amend.