As early as 1790 a law was passed in Pennsylvania, which is of importance in the history of this subject, showing appreciation of the principle of seclusion with labor. In the preamble it is declared, that previous laws for the punishment of criminals had failed of success, "from the _communication_ with each other not being sufficiently restrained within the places of confinement, and it is hoped _that the addition of unremitted solitude to laborious employment_, as far as it can be effected, will contribute as much to reform as to deter", and the Act further provides, that certain persons shall be "_kept separate and apart from each other_, as much as the convenience of the building will admit." The principle of separation, when first announced by Howard, and practically attempted in Pennsylvania, was imperfectly understood. It was easy to see the importance of separation; but how should it be applied? In Pennsylvania it was attempted at first with such rigor as to justify its designation as the _Solitary System_. But as the new penitentiary in Philadelphia was about to be occupied, a law was passed providing that after July 1st, 1829, convicts should, "instead of the penitentiary punishments heretofore prescribed, be sentenced to suffer punishment by _separate_ or solitary confinement at _labor_"; and there is further provision for "visits to the prisoners." Here were the two elements,--first, of labor, and, secondly, of visits. In pursuance of this Act, that penitentiary was organized at Philadelphia which afforded the first example on an extended scale of the absolute separation of convicts from each other, combined with labor. And this penitentiary has given its name to the class of prisons founded on this principle.