the Senate.[613] The assumption of the reins of government by a power, which as an independent authority was not contemplated in the original constitution, necessarily gave rise to a body of constitutional custom by the side of the older constitutional law. The applications of this new code can only be estimated by a more detailed treatment of the three factors of government—the magistracy, the people, and the Senate. CHAPTER IV THE MAGISTRACY § 1. _General Characteristics of the Magistracy_ The collective powers of the magistrate had, as we saw, been summed up in the word _imperium_; they had, perhaps, also been expressed by the vaguer term _potestas_. When, in course of time, magistracies were created which did not possess the _imperium_, _potestas_ was necessarily the only word which expressed the _generic_ power of the magistracy; _imperium_ became a special _species_ of this power. Thus one could speak of the _consulare imperium_ or of the _consularis potestas_, but only of the _tribunicia potestas_.[614] It is difficult to treat collectively of the special manifestations of this authority; for the magistracies were graduated by differences of power. To avoid confusion and repetition it will be best, in this general sketch, to give a complete list of magisterial powers, and to point out in each case where they are accorded to, or withheld from, the particular occupants of office. Magisterial powers may be divided into (i.) administrative, (ii.) those exercised in connexion with the people, (iii.) those exercised in connexion with the Senate; and (iv.) certain general powers which underlie all these spheres of activity—the right of interpreting the will of the gods through auspices, and the right of enforcing decrees. (i.) _Administrative powers._—The sphere of administrative activity had from the first days of the Republic been divided into the two departments of command at home (_domi_) and abroad (_militiae_), the dividing line between the two being sometimes the _pomerium_, sometimes the limit marked by the first milestone outside the city.[615]