The law and rules in these respects, as applied to United States prisoners, having also been under discussion in our Society, special information has been desired on that branch of the subject. It being understood that the General Government pays for their board, doubts have been expressed whether they are bound to labor at all; and if they do, it has been suggested that they should receive a credit for the _whole_ value of their work. The first branch of the question is answered and settled by the fact, that they are sentenced to under go imprisonment for a certain term, _in conformity with our State Laws_—that is, “at hard labor.” Next, as to compensation, their board being paid. It is true the United States pays for each of its prisoners $2.50 per week, which is for board, clothing, fuel, medical attendance, and, indeed, all his ordinary wants, and is hardly half of the cost to the Commonwealth, of each of those in confinement. The Penitentiary was erected by the State of Pennsylvania, at a cost of about $600,000, _for its own use_. The interest of this sum, and an annual appropriation made, to meet current expenses, such as salaries of officers, &c., amount together to about $50,000 per annum, which, as the average number in confinement does not exceed 400, makes a yearly cost to each of, say $125, _in addition to their board and incidentals_. It is fairly said, that, although we may be willing to submit to the loss on our own prisoners, it is but reasonable that we should be protected from it, when accommodating the General Government. The result is, that United States prisoners, as regards labor and compensation, are treated throughout in the same manner as our own. The same principle, as to compensation for labor, though differing somewhat in its practical details, has been introduced into our County Prison, with very satisfactory results. Whether it has been adopted in our Western State Penitentiary at Pittsburgh, or not, we are not clearly informed; and we are not aware that it is to be found in any Jail or Penitentiary beyond the limits of our State. It is one of the advantages of the Pennsylvania Separate System of imprisonment that it better admits of such an arrangement, than where the prisoners are congregated together in the workshops. E. H. BONSALL. _Philadelphia_, 11_th_ _Mo._ 19, 1863.