have not only difficult problems to settle for their pupils, but they are liable to be appealed to by the whole community, for solutions of questions, or for explanations of new phenomena of nature or art, which are supposed to belong to their respective departments. For several years, therefore, at least, a professor in any province of science or literature, will find time for little else than the exclusive study of the subjects of his profession. But, suppose him to have become master of this, so far as to be prepared. for all its probable exigencies, well-grounded in all the topics of his recitations and lectures, well-informed in all points of his profession, on which he is likely to be consulted by his pupils or others, then an important question arises: Shall he go on, with an exclusive devotion to the subjects which fall technically within his own department, or shall he afterwards give a portion of his time to kindred subjects, and to general knowledge? I answer, if his object is to make original discoveries in the line of his profession, or to gain fame and distinction abroad, then, it may be best for him to be the "man of one idea," and to know nothing else save the particular subject of his profession. Such a course will be the most likely of any to add to the sum of truth, and to gain him a deathless name. But, if his great object is to teacher, the question reMy advice would then be

become an accomplished quires a different answer. this: Let your profession be the one great object before the mind; devote to it your best hours, and best thoughts, directly; but indirectly carry out the

same great purpose by paying, systematically, a certain degree of attention to kindred subjects, more or less intimately related to it. Let the profession itself be contemplated under the similitude of a river, broad and deep, but as constituted of many lesser streams, by whose confluence it has been formed, and is still fed. The right kind of professional enthusiasm is that, which is so engrossed with a main purpose, as to look at everything in the light of that purpose, and to give to every smaller stream such a direction as to swell the main channel. There are, however, two kinds of professional enthusiasm; one, limits itself to the subjects that technically belong to its own profession, rejecting every other species of knowledge as irrelevant, or even, in the littleness of views which such a spirit is apt to engender, as useless. The other turns every thing into its own channel, and guides all the remotest streams of knowledge into the main current. A mind thus swayed by some great commanding object, cannot be diverted from its noble purpose, however wide its range of study or observation may seem to be, since it contemplates all subjects in their relations to that purpose. Such is the professional character which Cicero has so finely portrayed in the consummate orator, or summus orator. The high-minded and aspiring youth, has ever before him the lofty image of the accomplished advocate. Happy if pure science has trained his mind to close and vigorous thought - happy if the material world has enlarged his soul, by her lo ty contemplationshappy if the classics have refined his diction, and

supplied that affluence of language, that copia verborum, so useful to the orator-happy if the Muses have warmed and exalted his imagination, and enlivened and purified his wit. From these ample stores, laid up in a well-spent youth, he may, when so pressed with the duties of an arduous profession, as to have little opportunity for the cultivation of general knowledge, draw his weapons, as from an armory, to invigorate his argument, to illustrate his subject, to embellish his discourse, to deepen his pathos. Every attribute of the scholar lends its aid to form the accomplished orator.

The ministry of the Gospel supplies a still loftier motive for professional enthusiasm, as the interests of eternity are above those of time. I love the preacher, such as Paul, whose high commission is ever full in his view. His range of study may be wide; his intercourse with the world extensive and free; his fields of usefulness varied; but he must have continually in sight the great end of his ministry, and make all things subservient to his main design. I accompanied such a man to a beautiful vineyard, where the vines were hanging with the richest clusters. With me he admired the skill of the gardener, and the beauty of the garden. He had a high perception of the beautiful, both in nature and art; but all his emotions ran at once into the same current. "Herein, (said he,) is my Father glorified, that ye bear much fruit." But a more delightful and striking example of professional enthusiasm, will readily occur in the recollections of an eminent divine, with whose

history most of those present are doubtless familiar. I allude to the late Dr. Payson. Amid the last throes of a terrible disease, he was carried to the communion-table, almost in his winding-sheet. There he preached his farewell sermon, and with a palsied hand broke to his flock the bread of life. As has been well said, "like the miser grasping his gold," he died grasping his treasure, bearing on his corpse a paper, pinned by his own direction on his breast, with this inscription, "Remember the words which Ispake unto you while I was yet with you." When the heart is thus engrossed with some great and exalted purpose, which I have denominated professional enthusiasm, this purpose becomes the centre towards which every thing tends. It is a magnet of Herculean powers indeed, which collects, at once, its kindred metal, although scattered in particles among the sands of the sea-shore. What energy does this principle sometimes impart! A Carthaginian child is led to the altar by a revengeful father, and made to swear eternal hatred to the Romans. This purpose is cherished and fed by every device, until it infuses its unconquerable energies into the very life-blood. The child becomes a man, and in the prosecution of this purpose, how do the everlasting Alps melt away at his feet, and Rome's proud eagles cower before him! Now the very thing which appears to me necessary, in order to exalt the profession of the teacher to its proper level among the learned professions, is that it be recognized as one of the learned professions — that the gift of teaching be recognized as a peculiar

talent, of a rare and exalted kind and, to become an accomplished teacher be regarded, in itself, as a purpose worthy of the highest and noblest ambition. With such views of the subject, let us proceed to inquire,

2. What knowledge the teacher requires of kindred subjects, or those not technically embraced within his own department, but more or less intimately related to it; and what acquisitions he ought to make in general knowledge.

My remarks on this subject, will apply more appropriately to professors in the higher departments of science or literature, but will, I trust, have some useful bearing upon those whose labors are bestowed upon the more elementary branches of education.

In the first place, then, I hold that, in order to understand thoroughly any branch of science, it is necessary to know much, also, of various kindred sciences. Thus, no one can understand Chemistry well, without knowing something also of Mechanical Philosophy; and no one can be master of the mechanical laws of nature, without much knowledge also of the chemical laws. Each science has various relations to the other; and chemical and mechanical principles are often so intimately blended in the saine phenomenon, either of art or nature, that its full and complete explanation must involve both mechanical and chemical considerations. No ther the chemist nor the natural philosopher, is competent, alone, to understand the steam-engine. The development of the power of elastic steam, is chemical; the applica