agere praeceptis, quod fieri necesse est, quotiens imperitia praepositi ad illorum decurrit usum; quorum etsi necessariae partes sunt ad ministerium, tamen ut manus quaedam et instrumentum agentis. . . .1 Quapropter ea quae ad universam rem pertinentia contrahere potui, more iam per multa mihi officia servato in ordinem et velut corpus diducta in hunc commentarium contuli, quem pro formula administrationis respicere possem. In aliis autem libris, quos post experimenta et usum composui, succedentium res acta est; huius commentarii pertinebit fortassis et ad successorem utilitas, sed cum inter initia administrationis meae scriptus sit, in primis ad meam2 institutionem regulamque proficiet.
3. Ac ne quid ad totius rei pertinens notitiam praetermisisse videar, nomina primum aquarum, quae in urbem Romam influunt, ponam; tum per quos quaeque earum et quibus consulibus, quoto post urbem conditam anno perducta sit; dein quibus ex locis et a quoto miliario capta sit3 ac quantum subterraneo rivo, quantum substructione, quantum opere arcuato; post altitudinem cuiusque modulorumque . . .4 erogationes ab illis factae sint,
- 1Gap of about eleven letters in C. In this edition, the number of letters omitted in C will be indicated by a corresponding number of dots in the text, except where footnotes are added giving the size of the lacunae. In these cases the lacunae will regularly be indicated by three dots.
- 2iñã C; nostram B.
- 3Bennett; cepisse C; coepisset B.
- 4No gap in C, but B suggests supplying rationes.
of assistants. Yet precisely this is inevitable whenever a person inexperienced in the matter in hand has to have recourse to the practical knowledge of subordinates For though the latter play a necessary rôle in the way of rendering assistance, yet they are, as it were, but the hands and tools of the directing head. Observing, therefore, the practice which I have followed in many offices, I have gathered in this sketch (into one systematic body, so to speak) such facts, hitherto scattered, as I have been able to get together, which bear on the general subject, and which might serve to guide me in my administration. Now in the case of other books which I have written after practical experience, I consulted the interests of my successors. The present treatise also may be found useful by my successor, but it will serve especially for my own instruction and guidance, being prepared, as it is, at the beginning of my administration.
And lest I seem to have omitted anything requisite to a familiarity with the entire subject, I will first set down the names of the waters which enter the City of Rome; then I will tell by whom, under what consuls, and in what year after the founding of the City each one was brought in; then at what point and at what milestone each water was taken; how far each is carried in a subterranean channel, how far on substructures,1 how far on arches. Then I will give the elevation2 of each, [the plan] of the taps, and the distributions that are made from them;