below, and yet his own horizon be proportionately limited when compared to that of others who have climbed the still higher mountain above him. Can we not all bring home to our minds this varying value of our acquirements at successive periods of our lives? and are we not sometimes surprised to reflect that some problem was once difficult, or some fact obscure, which is now as familiar to our understandings as the daylight to our eyes? We have, in short, as regards these particular objects, passed from the night of ignorance into the day of knowledge. And us with the same individual, and even with whole classes of individuals, at different epochs, so is it with different individuals at the same time: one person holding in his hand the dim taper of ignorance, sees by its flickering and ill-directed light the object of his examination, distorted by partial and shifting shadows--just as some timid traveller on a dusky night sees in each waving bush, as to his alarmed imagination it grows to a portentous size, or assumes a fearful form, some aërial phantom, or some terrestrial monster. The other, raising the bright lamp of knowledge, dispels at once by its clear and steady light, uncertainty, and sees the object as it is. So many indeed are the practical illustrations of the different manner in which the same object is viewed by knowledge and by ignorance, that it is difficult to make a first choice. All around us there are objects, the nature and qualities of which are known to the few, unknown to the many, and hence either overlooked or misunderstood by the latter, studied and understood by the former. Each portion, however minute, of our own body, and of that of every other organic being, has in it wherewithal to exercise the ingenuity and reflection of the wisest; and yet how many thousands live and die without having even desired much less sought after such knowledge! Nor is the inorganic world less fruitful in subjects of inquiry, nor less neglected. The ploughman “whistles as he goes for want of thought,” not because nature has failed to spread around him inexhaustible food for thought, but because his mind has not been trained to think. By each movement of his ploughshare, page after page, as it were, is opened to his view of new and interesting matter--and yet he sees before him nothing but silent and unmeaning clods. By each movement of his foot he disturbs those pebbles which, speechless to him because he questions not, return to the interrogations of knowledge wonder-stirring answers, when asked, 1. Of what they are composed? 2. Whence they came? 3. And how they came?