Lawyers, clergymen, editors, farmers, and even post masters, have all in turn been swindled by means of facilities afforded by the post-office system, the frauds ranging in magnitude and importance, from imaginary papers of onion seed, to "calls" for ministerial aid in the momentous work of converting "a world lying in wickedness!" It is with a view to put those who may peruse these pages on their guard, that a few rare specimens of the tricks of these "Jeremy Diddlers" are here exposed, most of which have come to light within a few months of this present writing. The first that we will describe, was perpetrated quite successfully upon the legal fraternity, and some of the most distinguished members of that highly useful profession in the different States, will no doubt readily recognise the truthfulness of the picture, as it is held up to their gaze. This "dodge" may properly be entitled YOUNG AMERICA PRACTISING _AT_ THE BAR. In January of the present year, the post master of Brooklyn, N. Y., called my attention to the fact that large numbers of letters were arriving at that office to the address of "William H. Jolliet," and that from some information he had received, he was led to believe that the correspondence was in some way connected with a systematic scheme of fraud. Arrangements were accordingly made to watch the person who was in the habit of inquiring for the "Jolliet" letters, and the next time he called, which was in the evening, he was followed as far as the Fulton ferry, detained just as he was about to enter the ferry-boat, and questioned in reference to the letters. The person thus interrogated was an exceedingly intelligent boy, about fifteen years of age, plainly but neatly dressed, and of prepossessing manners, particularly for one so young. When asked what he intended to do with the letters he had just taken from the post-office, he manifested great self-possession, and apparently anticipating trouble, without allowing an opportunity for a second question, he hurriedly asked, "Why, what about this business? I have been thinking there might be something wrong about Jolliet's letters. I am a student in a respectable law-office in New York, and would not like to be involved in any trouble of this sort. I can tell you, sir, all I know about these letters." As his explanation will hereafter appear in full, suffice it here to say, that he threw the entire responsibility upon a stranger whom he accidentally met in the Harlem cars. The story was told with much apparent frankness, and a gentleman passing along who knew the lad, and confirmed his statement as to his connection with a prominent law-office in New York, he was allowed to go at large, under a promise that at an appointed hour on the following day, he would call on the Brooklyn post master, explain the matter more fully, and put him in possession of facts which would enable the officers to arrest Jolliet, if that was thought best.