During the vacation, I had looked forward with confidence to the pleasure of listening to-night to an address from one of the ablest experimenters and most vigorous writers that this Society has ever numbered amongst its members,—Sir David Brewster. And when, a short time since, I learnt that I had been indulging an ill-founded expectation, and that the duty of opening the session was to fall to my own lot, I experienced something more than disappointment. For, in addition to my imperfect knowledge of the past history and present position of the Society, is the fact that I had made no preparation, either in the way of collecting materials, or of providing a reserve of time, for drawing up an address. I must therefore come before you with an apology. I must crave your forbearance should some of the remarks which I make appear trite and unworthy of the occasion,—should others be traceable to what I have said elsewhere,—should all be found crude and lower in tone than beseems the position in which your kindness places me.