roduced in America at a cost and in a quantity to stimulate the
development of concrete construction, engineers began with rough
broken stone and sand as the constituents of what they call the
aggregate, but some one soon "discovered" that the use of smooth
natural gravel made more compact concrete and "gravel concrete" became
the last word in engineering practice. But it was older even than
Varro. A Chicago business man visiting Mycenae picked up and brought
home a bit of rubbish from Schliemann's excavations of the ancient
masonry: lying on his office desk it attracted the attention of an
engineering friend who exclaimed, "That is one of the best samples of
the new gravel concrete I have seen. Did it come out of the Illinois
tunnel?" "No," replied the returned traveller, "it came out of the
tomb of Agamemnon!"]

[Footnote 72: Varro here seems to forget the unities. He speaks in his
own person, when Scrofa has the floor.]

[Footnote 73: It will be recalled that Aristotle described slaves as
living tools. In Roman law a slave was not a _persona_ but a _res_.
Cf. Gaius II, 15.]

[Footnote 74: One of the most interesting of these freemen labourers of
whom we know is that Ofellus whom Horace (Satire II, 2) tells us
was working with cheerful philosophy as a hired hand upon his
own ancestral property from which he had been turned out in the
confiscations following the battle of Philippi. This might have been
the fate of Virgil also had he not chanced to have powerful friends.]

[Footnote 75: "Mais lorsque, malgre le degout de la chaine domestique,
nous voyons naitre entre les males et les femelles ces sentiments
que la nature a partout fondes sur un libre choix: lorsque l'amour a
commence a unir ces couples captifs, alors leur esclavage, devenu pour
eux aussi doux que la douce liberte, leur fait oublier peu a peu
leur droits de franchise naturelle et les prerogatives de leur etat
sauvage; et ces lieux des premiers plaisirs, des premieres amours,
ces lieux si chers a tout etre sensible, deviennent leur demeure de
predilection et leur habitation de choix: l'education de la famille
rend encore cette affection plus profonde et la communique en meme
temps aux petits, qui s'etant trouves citoyens par naissance d'un
sejour adopte par leur parents, ne cherchent point a en changer: car
ne pouvant avoir que pen ou point d'idee d'un etat different ni d'un
autre sejour ils s'attachent au lieu ou ils sont nes comme a leur
patrie; et