That there are great natural differences of talent for letter-writing is certainly true; but it is equally true that there are great natural differences of talent for oral explanation, yet, although we constantly hear people say that this or that matter of business cannot be treated by correspondence, we _never_ hear them say that it cannot be treated by personal interviews. The value of the personal interview is often as much over-estimated as that of letters is depreciated; for if some men do best with the tongue, others are more effective with the pen. It is presumed that there is nothing in correspondence to set against the advantages of pouring forth many words without effort, and of carrying on an argument rapidly; but the truth is, that correspondence has peculiar advantages of its own. A hearer seldom grasps another person's argument until it has been repeated several times, and if the argument is of a very complex nature the chances are that he will not carry away all its points even then. A letter is a document which a person of slow abilities can study at his leisure, until he has mastered it; so that an elaborate piece of reasoning may be set forth in a letter with a fair chance that such a person will ultimately understand it. He will read the letter three or four times on the day of its arrival, then he will still feel that something may have escaped him, and he will read it again next day. He will keep it and refer to it afterwards to refresh his memory. He can do nothing of all this with what you say to him orally. His only resource in that case is to write down a memorandum of the conversation on your departure, in which he will probably make serious omissions or mistakes. Your letter is a memorandum of a far more direct and authentic kind. Appointments are sometimes made in order to settle a matter of business by talking, and after the parties have met and talked for a long time one says to the other, "I will write to you in a day or two;" and the other instantly agrees with the proposal, from a feeling that the matter can be settled more clearly by letter than by oral communication. In these cases it may happen that the talking has cleared the way for the letter,--that it has removed subjects of doubt, hesitation, or dispute, and left only a few points on which the parties are very nearly agreed.