The different forms employed in epistolary correspondence are numerous, far more numerous than generally supposed. To illustrate: four hundred letters, written by as many different persons, and all addressed to the same person, were, without examination, divided into one hundred parcels of four letters each. They were then examined in regard to the form employed by the writer. The heading, the address, the introduction, and the subscription were noted--no attention being paid to the body of the letter, or the signature. In not one of these one hundred parcels were found four letters having the same form. The heading of these letters exhibited nine different forms; the address, fourteen; the introduction, eight; and the subscription, eleven. Again, nearly every writer employs certain idioms of language that are peculiar to him, and which reveal his identity, even though he tries to conceal it. Let us now institute a brief analysis of the four letters under consideration. Errors will be noticed, not for the purpose of reflecting upon the literary attainments of the writer, but solely with a view of discovering his identity. These are mostly of a trivial character, confined to marks of punctuation, etc.; and it is a recognized fact that a majority of educated persons, including many professional writers, are more or less deficient in the art of punctuation. In proof of the common authorship of these four letters, the following reasons are submitted: 1. In all of them we recognize a stiff formality--a studied effort to conform to one ideal standard. 2. All of them were written at Springfield, Ill., and all omit the name of the state. 3. In each of them, the day of the month is followed by the suffix, "th." This, if not wholly improper, is not common usage. Had these letters been written by the four persons to whom they are ascribed, at least three of them would have omitted it. 4 In all, but one, the address is "Rev. J. A. Reed," and in the exception the writer merely substitutes "Jas." for "J." 5. In each of them the address is followed by a colon instead of a comma, the proper mark to use. Had they been written by four persons, it is possible that a part, or even all, would have made an error, but it is highly improbable that all would have made the _same_ error. 6. In these letters, the introductory words are uniformly "Dear Sir"--the most common form of introduction, and the one that a writer, in drafting a letter addressed to himself, would most naturally employ. 7. In every instance, the introduction is followed by a dash instead of a colon--a uniformity of error, again. 8. In the subscription, the term, "Yours truly," is invariably used, except in the Lewis letter, which concludes with "Yours, etc." 9. The Edwards letter and the Lewis letter begin with the same idea, expressed in nearly the same words. Edwards is made to say, "A short time after the Rev. Dr. Smith," etc.; and Lewis--"Not long after Dr. Smith."