If I were to name one branch, as more important to a young man than any other,--next to the merest elements of reading and writing--it would be chemistry. Not a mere smattering of it, however; for this usually does about as much harm as good. But a thorough knowledge of a few of the simple elements of bodies, and some of their most interesting combinations, such as are witnessed every day of our lives, but which, for want of a little knowledge of chemistry, are never understood, would do more to interest a young man in the business in which he may be employed, than almost any thing I could name. For there is hardly a single trade or occupation whatever, that does not embrace a greater or less number of chemical processes. Chemistry is of very high importance even to the gardener and the farmer. There are several other branches which come under the general head of NATURAL SCIENCE, which I recommend to your attention. Such are BOTANY, or a knowledge of plants; NATURAL HISTORY, or a knowledge of animals; and GEOLOGY, or a general knowledge of the rocks and stones of which the earth on which we live is composed. I do not think these are equally important with the knowledge of chemistry, but they are highly interesting, and by no means without their value. 5. GRAMMAR AND COMPOSITION. The foundation of a knowledge of Grammar is, in my view, Composition; and composition, whether learned early or late, is best acquired by _letter writing_. This habit, early commenced, and judiciously but perseveringly followed, will in time, ensure the art not only of composing well, but also grammatically. I know this position is sometimes doubted, but the testimony is so strong, that the point seems to me fully established. It is related in Ramsay's Life of Washington, that many individuals, who, before the war of the American Revolution, could scarcely write their names, became, in the progress of that war, able to compose letters which were not only intelligible and correct, but which would have done credit to a profound grammarian. The reason of this undoubtedly was, that they were thrown into situations where they were obliged to write much and often, and in such a manner as to be clearly understood. Perhaps the misinterpretation of a single doubtful word or sentence might have been the ruin of an army, or even of the _cause_. Thus they had a motive to write accurately; and long practice, with a powerful motive before them, rendered them successful. Nor is it necessary that motives so powerful should always exist, in order to produce this result;--it is sufficient that there be a motive to _write well_, and to _persevere_ in writing well. I have known several pedlars and traders, whose business led to the same consequences. 6. LETTER WRITING.