Trivium Pursuit

Frontinus — What’s Wrong With This Picture Contest

Read here below the excerpts from On Water. The first person to tell us “What’s Wrong With This Picture” wins a copy of The Fallacy Detective. Leave your guess in the comments section here.

Frontinus (Sextus Julius Frontinus)
C. A.D. 40-103

Frontinus was a Roman soldier and author. He served as governor of Britain and later as superintendent of the aqueducts at Rome.


On Water (2 books) – A history and description of the water supply of Rome; laws concerning the use of water.

The Stratagems (4 books) – The rules of military science.


On Water

1.25 Later on, an ajutage called a quinaria came into use in the City, to the exclusion of the former measures. This was based neither on the inch, nor on either of the digits, but was introduced, as some think, by Agrippa, or, as others believe, by plumbers at the instance of Vitruvius, the architect. Those who represent Agrippa as its inventor, declare it was so designated because five small ajutages or punctures, so to speak, of the old sort, through which water used to be distributed when the supply was scanty, were now united in one pipe. Those who refer it to Vitruvius and the plumbers, declare that it was so named from the fact that a flat sheet of lead 5 digits wide, made up into a round pipe, forms this ajutage. But this is indefinite, because the plate, when made up into a round shape, will be extended on the exterior surface and contracted on the interior surface. The most probable explanation is that the quinaria received its name from having a diameter of 5/4 of a digit, a standard which holds in the following ajutages also up to the 20‑pipe, the diameter of each pipe increasing by the addition of 1/4 of a digit. For example the 6‑pipe is six quarters in diameter, a 7‑pipe seven quarters, and so on by a uniform increase up to a 20‑pipe.

1.36 But the position of the calix is also a factor. Placed at right angles and level, it maintains the normal quantity. Set against the current of the water, and sloping downward, it will take in more. If it slopes to one side, so that the water flows by, and if it is inclined with the current, that is, is less favorably placed for taking in water, it will receive the water slowly and in scant quantity. The calix, now, is a bronze ajutage, inserted into a conduit or reservoir, and to it the service pipes are attached. Its length ought not to be less than 12 digits, while its orifice ought to have such capacity as is specified. Bronze seems to have been selected, since, being hard, it is more difficult to bend, and is not easily expanded or contracted.

2.105 Whoever wishes to draw water for private use must seek for a grant and bring to the commissioner a writing from the sovereign; the commissioner must then immediately expedite the grant of Caesar, and appoint one of Caesar’s freedmen as his deputy for this service. Tiberius Claudius appears to have been the first man to appoint such a deputy after he introduced Claudia and New Anio. The overseers must also be made acquainted with the contents of the writing, that they may not excuse their negligence or fraud on the plea of ignorance. The deputy must call in the levellers and provide that the calix is stamped as conforming to the deeded quantity, and must study the size of the ajutages we have enumerated above, as well as have knowledge of their location, lest it rest with the caprice of the levellers to approve a calix of sometimes greater, or sometimes smaller, interior area, according as they interest themselves in the parties. Neither must the deputy permit the free option of connecting directly to the ajutages any sort of lead pipe, but there must rather be attached for a length of •fifty feet one of the same interior area as that which the ajutage has been certified to have, as has been ordained by a vote of the Senate which follows:

2.115 The following mode of gaining money, practised by the water-men, is also to be abolished; the one called “puncturing.” There are extensive areas in various places where secret pipes run under the pavements all over the City. I discovered that these pipes were furnishing water by special branches to all those engaged in business in those localities through which the pipes ran, being bored for that purpose here and there by the so‑called “puncturers”; whence it came to pass that only a small quantity of water reached the places of public supply. How large an amount of water has been stolen in this manner, I estimate by means of the fact that a considerable quantity of lead has been brought in by the removal of that kind of branch pipes.

2.118 The wages of the State gang are paid from the State treasury, an expense which is lightened by the receipt of rentals from water-rights, which are received from places or buildings situated near the conduits, reservoirs, public fountains, or water-basins. This income of nearly 250,000 sestertii formerly lost through loose management, was turned in recent times into the coffers of Domitian; but with a due sense of right the Deified Nerva restored it to the people. I took pains to bring it under fixed rules, in order that it might be clear what were the places which fell under this tax. The gang of Caesar gets its wages from the emperor’s privy purse, from which are also drawn all expenses for lead and for conduits, reservoirs, and basins.

2.124 I think no one will doubt that the greatest care should be taken with the aqueducts nearest to the City (I mean those inside the seventh mile-stone, which consist of block-stone masonry), both because they are structure of the greatest magnitude, and because each one carries several conduits; for should it once be necessary to interrupt these, the City would be deprived of the greater part of its water-supply. But there are methods for meeting even these difficulties: provisional works are built up to the level of the conduit which is being put out of use, and a channel, formed of leaden troughs, running along the course of the portion that has been cut off, again provides a continuous passage. Furthermore, since almost all the aqueducts ran through the fields of private parties and it seemed difficult to provide for future outlays without the help of some constituted law; in order, also, that contractors should not be prevented by proprietors from access to the conduits for the purpose of making repairs, a resolution of the Senate was passed, which I give below.

6 Responses to “Frontinus — What’s Wrong With This Picture Contest”

  1. Ruth Says:

    Hi there,
    I’m not sure exactly what you mean by “WHat’s wrong with this picture” but I don’t think that using lead for all these water pipes sounds like a very good plan. Isn’t lead pretty dangerous for human consumption?


  2. Laurie Bluedorn Says:

    You’re correct and the winner!!! Send me your address and I’ll mail you a copy of The Fallacy Detective.

  3. Ruth Says:

    Thanks Laurie!
    I have left a note through the “Contact Us” response form with my address on it.

    Thanks again!

  4. Laurie Bluedorn Says:

    Our winner is Ruth van den Brink from New Zealand. We’ll be sending her a copy of The Fallacy Detective today.

  5. Kristen B. Says:

    I recently started reading The Fallacy Detective and it is excellent. :) I’m really enjoying it!

  6. Perla Sarmiento de Adams Says:

    The blog come back… very good!