Three classes of people range themselves around us-the aged, the middle-aged, and the young. To each belong hopes and fears, joys and sorrows, peculiar to itself. As men of gray hairs have trials and comforts which may very properly be deminated their own, so it is also with those in the meridian of life, and with bright and buoyant youth. At every different period, existence assumes a new phase, and requires to be addressed in new and appropriate terms. None of these groups of human beings must be overlooked; but if it be right to discriminate, we can easily see where our chief interest should be concentrated. To be useful to the young is to be useful for the longest time, and on the largest scale.