Next to the letters of the great Roman orator, merit points to those of the philosopher Seneca. He, too, cultivates and enjoins an easy and unstudied diction. So great is the excellence of his letters; so nearly is their beauty allied to the beauty of our Holy Scriptures; so does he seem to anticipate the morals and teachings of our Christian dispensation, that it is almost reprehensible to speak of them at all, without setting forth their extraordinary charms of style and thought, even in a larger space than the present article can be allowed to occupy. After Seneca, the next most noted of the ancient letter writers was Pliny the younger. And now we are brought down to the days of the Apostles and their Epistles. With a simple reverential allusion to the letters of St. Paul and the other immediate followers of our Lord, letters that teach men the way of salvation--we pass to a more modern consideration of our topic. Letters can hardly be classified. They are of various sorts. Most of them, as schoolboys say, end in t-i-o-n, _tion_. There are Letters of Introduction; Letters of Congratulation; Letters of Consolation; Letters of Invitation; Letters of Recommendation; Letters of Administration. There are, moreover, letters of friendship, business letters, letters of diplomacy, letters of credit, letters patent, letters of marque (apt also to be letters of mark), and love letters--the last being by no means least. Let not the gentle reader imagine from this enumeration than we are going to be so tedious as to divide the remainder of this article into heads, and to treat of each one of these kinds of letters in its turn. No; our object is, by indicating thus the number of sorts, to elucidate the importance of letters, and to prove that, if their writing be not, like that of poetry, ranked among the fine arts, it well deserves to be. For what more admirable accomplishment can there be--what is of more importance often than the proper composing of letters? Many a reputation is made or marred by a single epistle. Great consequences follow in the train of a single epistle. The pen is mightier than the sword. How well may our readers remember one brief letter of Henry Clay (_clarum et venerabile nomen!_), who, when a candidate for the Presidency, wrote many excellent letters, and too many--so many, indeed, that his adversaries indulged in pointless ridicule, and called him 'The Complete Letter Writer.' We allude, of course, to that brief letter to certain importunate individuals in Alabama, which lost for him the decisive and final vote of New York, and made Mr. Polk President--its consequences being the war with Mexico, the acquisition and annexation of California, the discovery of the gold mines--working an utter change in the political and commercial fortunes of the world, which would probably never have taken place, or, at least, not in our century, but for that one brief Alabama letter! It is, we believe, fully conceded that the