Lack of technological progress in late Roman Empire

[Dan Diffendale]

41

C. PLINIVS TRAIANO IMPERATORI

1 Intuenti mihi et fortunae tuae et animi magnitudinem conuenientissimum uidetur demonstrari opera non minus aeternitate tua quam gloria digna, quantumque pulchritudinis tantum utilitatis habitura. 2 Est in Nicomedensium finibus amplissimus lacus. Per hunc marmora fructus ligna materiae et sumptu modico et labore usque ad uiam nauibus, inde magno labore maiore impendio uehiculis ad mare deuehuntur ... hoc opus multas manus poscit. At eae porro non desunt. Nam et in agris magna copia est hominum et maxima in civitate, certaque spes omnes libentissime aggressuros opus omnibus fructuosum. 3 Superest ut tu libratorem vel architectum si tibi videbitur mittas, qui diligenter exploret, sitne lacus altior mari, quem artifices regionis huius quadraginta cubitis altiorem esse contendunt. 4 Ego per eadem loca invenio fossam a rege percussam, sed incertum utrum ad colligendum umorem circumiacentium agrorum an ad committendum flumini lacum; est enim imperfecta. Hoc quoque dubium, intercepto rege mortalitate an desperato operis effectu. 5 Sed hoc ipso - feres enim me ambitiosum pro tua gloria - incitor et accendor, ut cupiam peragi a te quae tantum coeperant reges.

(From The Latin Library)

quadraginta cubitis, 40 cubits, that is, 40 x ca. 45 cm for the Roman cubit, gives 18 meters.

And the translation from Project Gutenberg:

To THE EMPEROR TRAJAN

WHEN I reflect upon the splendour of your exalted station, and the
magnanimity of your spirit, nothing, I am persuaded, can be more
suitable to both than to point out to you such works as are worthy
of your glorious and immortal name, as being no less useful than
magnificent. Bordering upon the territories of the city of
Nicomedia is a most extensive lake; over which marbles, fruits,
woods, and all kinds of materials, the commodities of the country,
are brought over in boats up to the high-road, at little trouble and
expense, but from thence are conveyed in carriages to the sea-side,
at a much greater charge and with great labour. To remedy this
inconvenience, many hands will be in request; but upon such an
occasion they cannot be wanting: for the country, and particularly
the city, is exceedingly populous; and one may assuredly hope that
every person will readily engage in a work which will be of
universal benefit. It only remains then to send hither, if you shall
think proper, a surveyor or an architect, in order to examine
whether the lake lies above the level of the sea; the engineers of
this province being of opinion that the former is higher by forty
cubits, I find there is in the neighbourhood of this place a large
canal, which was cut by a king of this country; but as it is left
unfinished, it is uncertain whether it was for the purpose of
draining the adjacent fields, or making a communication between
the lake and the river. It is equally doubtful too whether the death
of the king, or the despair of being able to accomplish the design,
prevented the completion of it. If this was the reason, I am so
much the more eager and warmly desirous, for the sake of your
illustrious character (and I hope you will pardon me the ambition),
that you may have the glory of executing what kings could only
attempt.

LI

TO PLINY

THERE is something in the scheme you propose of opening a
communication between the lake and the sea, which may, perhaps,
tempt me to consent. But you must first carefully examine the
situation of this body of water, what quantity it contains, and from
whence it is supplied; lest, by giving it an opening into the sea, it
should be totally drained. You may apply to Calpurnius Macer for
an engineer, and I will also send you from hence some one skilled
in works of this nature.

It seems the "Ship lock" is implied rather than explicit.