His commission is a roving one, and his command seems to be limited neither to kind or number. Many of his men are citizens, who spend a portion of their time in their ordinary business, and who hold themselves in readiness for any movements indicated by their commander-in-chief. Occasionally he is accompanied and assisted in his forays by daring men from various commands, who are at home on leaves of absence or furloughs, while a few seem to be directly and continually under his control. The principal stimulus of the entire party (except the bad whiskey which they are said to use), is the plunder which they share. It is their custom at times to parole their prisoners and send them back to our lines, though often, when large numbers are taken, they are sent to Richmond; but all horses and equipments, which now command enormous prices in Dixie, are the property of the captors. The region of the country they have chosen for their operations is certainly well adapted to facilitate their designs. Deep ravines traverse the country, skirted with dense, dark foliage, which affords them shelter, and through which they pass like so many wild turkeys or wild boars, knowing, as they do, all the roads and by-paths. Indeed, some of their parties are dwellers in these regions, and are acquainted with every nook and corner, where they can hide securely with their prey and elude their pursuers. When the immediate neighborhoods of their depredations do not offer a sufficient asylum, they fly to the fastnesses and caverns of the Bull Run Mountains. Then, too, there is a certain degree of carelessness on the part of our own men, which merits censure and causes trouble. For instance, they frequently call at the homes of bitter Rebels for the purposes of pleasure, or to get articles of food, which they purchase or take, and while at these places they are too free to talk about the condition of our army, the position of our picket lines and posts, etc.--information which is grasped with wonderful avidity and as readily transmitted to Mosby and his men. Scarcely does any important event transpire among us, that is not fully understood immediately by the Rebel families within our lines, and is very easily borne to those outside the lines between two days. Thus movements even in contemplation have been heralded before the incipient steps had been taken, and consequently thwarted. Our only safety from this source of trouble would be to drive out of our lines all Rebel families, thus preventing the means of communicating the news to the outer world.