ground if I open my hand,' I should open my hand and let it fall. Take nothing for granted as known; inform the eye at the same time as you address the ear." It is of interest here--after seeing how Faraday as a lecturer impressed others--to note some of the remarks which he made on the subject of lectures, lecturers, and lecturing in his early correspondence with his friend, Benjamin Abbott. Several long letters on this matter passed between the friends, and Faraday (he was twenty-one at the time) not only speaks in a discriminating manner with regard to lectures, but he also treats with his native good sense of lecture rooms, apparatus, etc. All his remarks, he says in his earliest letter to Abbott on the subject, are the result of his own personal observation. The most necessary quality for a lecturer, says the youthful Faraday, is a good delivery; he then dwells upon the necessity of illustrating a lecture with experiments wherever possible. (How well he carried this rule into practice has been seen in an earlier part of this chapter, where we learned of some of his Juvenile Lectures being illustrated by upwards of eighty experiments.) "A lecturer," he goes on to say, "should appear easy and collected, undaunted and unconcerned,[10] his thoughts about him, and his mind clear and free for the contemplation and description of his subject." He then says, and we instantly think of the "time" card he had placed before him later, "I disapprove of long lectures; one hour is long enough for anyone, nor should they be allowed to exceed that time." The last of this series of letters on lectures commences in a style of genial banter, which, as it illustrates the lighter side of Faraday's character, merits quotation. "Dear Abbott," he writes, "As when on some secluded branch in forest far and wide sits perched an owl, who, full of self-conceit and self-created wisdom, explains, comments, condemns, ordains, and orders things not understood, yet full of his importance still holds forth to stocks and stones around--so sits and scribbles Mike; so he declaims to walls, stones, tables, chairs, hats, books, pens, shoes, and all the things inert that be around him, and so he will to the end of the chapter."